Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Nobuaki Egashira Last modified date:2019.07.29

Associate Professor / Clinical Pharmacology and Biopharmaceutics / Pharmacy / Kyushu University Hospital


Papers
1. Suetsugu K, Mori Y, Yamamoto N, Shigematsu T, Miyamoto T, Egashira N, Akashi K, Masuda S, Impact of CYP3A5, POR, and CYP2C19 polymorphisms on trough concentration to dose ratio of tacrolimus in allogeneic hematopoietic stem cell transplantation, Int J Mol Sci, 10.3390/ijms20102413, 20, 10, 50-58, 2019.05.
2. Nogami-Hara A, Kubota K, Takasaki K, Watanabe T, Egashira N, Iba H, Fujikawa R, Katsurabayashi S, Hatip FB, Hatip-Al-Khatib I, Iwasaki K, Extract of Yokukansan improves anxiety-like behavior and increases serum brain-derived neurotrophic factor in rats with cerebral ischemia combined with amyloid-β42 peptide, J Trad Chin Med, 39, 1, 50-58, 2019.02.
3. Shota Yamamoto, Nobuaki Egashira, Tsuda Makoto, Satohiro Masuda, Riluzole prevents oxaliplatin-induced cold allodynia via inhibition of overexpression of transient receptor potential melastatin 8 in rats, Journal of Pharmacological Sciences, 10.1016/j.jphs.2018.10.006, 138, 3, 214-217, 2018.11, Oxaliplatin causes acute cold hypersensitivity in most patients. We previously reported oxalate derived from oxaliplatin induced cold allodynia via overexpression of transient receptor potential melastatin 8 (TRPM8) in the dorsal root ganglion (DRG) in rats. In this study, we examined the effect of riluzole on oxaliplatin-induced cold allodynia. In cultured DRG neurons, riluzole suppressed oxalate-induced increase of the number of menthol (TRPM8 agonist)-sensitive cells. Moreover, riluzole prevented cold allodynia and increase in levels of TRPM8 mRNA in oxaliplatin-treated rats. These results suggest that riluzole prevents oxaliplatin-induced cold allodynia via inhibition of TRPM8 overexpression in the DRG..
4. Ai Nogami-Hara, Masaki Nagao, Kotaro Takasaki, Nobuaki Egashira, Risako Fujikawa, Kaori Kubota, Takuya Watanabe, Shutaro Katsurabayashi, Funda Bolukbasi Hatip, Izzettin Hatip-Al-Khatib, Katsunori Iwasaki, The Japanese Angelica acutiloba root and yokukansan increase hippocampal acetylcholine level, prevent apoptosis and improve memory in a rat model of repeated cerebral ischemia, Journal of Ethnopharmacology, 10.1016/j.jep.2017.12.025, 214, 190-196, 2018.03, Ethnopharmacological relevance Japanese Angelica acutiloba root (Angelica root) is included in several Kampo medicines including Yokukansan (YKS). Angelica root and YKS are used for the treatment of a variety of psychological and neurodegenerative disorders. Development of safe and effective therapeutic agents against cerebrovascular disorders will improve the treatment of patients with dementia. Aim of the study The effect of Angelica root and YKS on ischemia-impaired memory has not yet been fully investigated. The present study investigated whether Angelica root is also involved in memory improving and neuroprotective effect of YKS in a model of cerebrovascular ischemia. Materials and methods Male Wistar rats grouped into sham rats received saline, and other three groups subjected to repeated cerebral ischemia induced by 4-vessel occlusion (4-VO), received a 7-day oral administration of either saline, Angelica root or YKS. Memory was evaluated by eight-arm radial maze task. Acetylcholine release (ACh) in the dorsal hippocampus was investigated by microdialysis-HPLC. Apoptosis was determined by terminal deoxynucleotidyl transferase (TdT)-mediated fluorescein-deoxyuridine triphosphate (dUTP) nick-end labeling. Results Ischemia induced apoptosis, reduced release of ACh, and impaired the memory (increased error choices and decreased correct choices). Angelica root and YKS improved the memory deficits, upregulated the release of ACh and prevented 4-VO-induced hippocampal apoptosis. Conclusion The dual ACh-increasing and neuroprotective effect of Angelica root could make it a promising therapeutic agent useful for the treatment of symptoms of cerebrovascular dementia. Angelica root could be one of the components contributing to the memory-improving and neuroprotective effects of YKS..
5. Nobuaki Egashira, Yuki Akiyoshi, Hikari Iba, Takashi Arai, Izzettin Hatip-Al-Khatib, Kenichi Mishima, Katsunori Iwasaki, Tokishakuyakusan ameliorates spatial memory deficits induced by ovariectomy combined with β-amyloid in rats, Journal of Pharmacological Sciences, 10.1016/j.jphs.2018.01.005, 136, 3, 149-154, 2018.03, Previously, we reported that ovariectomy (OVX) combined with β-amyloid peptide (Aβ) impaired spatial memory by decreasing extracellular acetylcholine (ACh) levels in the dorsal hippocampus. Here, we investigated the effect of tokishakuyakusan (TSS), a Kampo medicine, on the impairment of spatial memory induced by OVX combined with Aβ in rats. Repeated administration of TSS (300 mg/kg, p.o.) significantly decreased the number of errors in the eight-arm radial maze test. Though TSS had no effect on extracellular ACh levels at baseline, TSS significantly increased extracellular ACh levels in the dorsal hippocampus. These results suggest that TSS improves the impairment of spatial memory induced by OVX combined with Aβ by (at least in part) increasing extracellular ACh levels in the dorsal hippocampus..
6. Nobuaki Egashira, Naoki Kubota, Yu Goto, Takuya Watanabe, Kaori Kubota, Shutaro Katsurabayashi, Katsunori Iwasaki, The antipsychotic trifluoperazine reduces marble-burying behavior in mice via D2 and 5-HT2A receptors
Implications for obsessive–compulsive disorder, Pharmacology Biochemistry and Behavior, 10.1016/j.pbb.2017.12.006, 165, 9-13, 2018.02, Trifluoperazine, a typical antipsychotic drug, not only antagonizes dopamine D2 receptors but also enhances serotonin 5-HT2 receptor-mediated behavior. Moreover, trifluoperazine suppresses human purinergic receptor P2X7 responses and calmodulin. However, the effect of trifluoperazine on marble-burying behavior, which has been considered an animal model of obsessive–compulsive disorder (OCD), has not been studied. Here, we examined the effect of trifluoperazine on marble-burying behavior in mice. Oral administration of paroxetine, a selective serotonin reuptake inhibitor, significantly reduced marble-burying behavior without affecting total locomotor activity. Similar results were obtained for trifluoperazine (3 mg/kg). The D2 receptor agonist, quinpirole (0.03 mg/kg, intraperitoneal [i.p.]), and 5-HT2A receptor antagonist, ketanserin (0.3 mg/kg, i.p.), significantly counteracted this reduction of marble-burying behavior by trifluoperazine. These results show that trifluoperazine reduces marble-burying behavior via D2 and 5-HT2A receptors, and may be a useful drug for the treatment of OCD..
7. Nobuaki Egashira, Emi Koushi, Takayuki Myose, Akito Tanoue, Kenichi Mishima, Ryota Tsuchihashi, Junei Kinjo, Hiroyuki Tanaka, Satoshi Morimoto, Katsunori Iwasaki, Role of vasopressin V1a receptor in ∆9-tetrahydrocannabinol-induced cataleptic immobilization in mice, Psychopharmacology, 10.1007/s00213-017-4735-1, 234, 23-24, 3475-3483, 2017.12, Rationale: Cannabis is a widely used illicit substance. ∆9-tetrahydrocannabinol (THC), the major psychoactive component of cannabis, is known to cause catalepsy in rodents. Recent studies have shown that vasopressin V1a and V1b receptors are widely distributed in the central nervous system and are capable of influencing a wide variety of brain functions such as social behavior, emotionality, and learning and memory. Objectives: The present study was designed to examine the possible involvement of V1a and V1b receptors in THC-induced catalepsy-like immobilization. Methods: The induction of catalepsy following treatment with THC (10 mg/kg, i.p.) or haloperidol (1 mg/kg, i.p.) was evaluated in wild-type (WT), V1a receptor knockout (V1aRKO), and V1b receptor knockout (V1bRKO) mice. The effect of treatment with the selective 5-hydroxytryptamine1A receptor antagonist WAY100635 (0.1 mg/kg, i.p.) on THC-induced catalepsy was also evaluated in V1aRKO mice. Moreover, the effects of the V1a receptor antagonist VMAX-357 and the V1b receptor antagonist ORG-52186 on THC-induced catalepsy were evaluated in ddY mice. Results: THC and haloperidol markedly caused catalepsy in V1bRKO mice as well as in WT mice. However, V1aRKO mice exhibited a reduction in catalepsy induced by THC but not by haloperidol. WAY100635 dramatically enhanced THC-induced catalepsy in V1aRKO mice. Although VMAX-357 (10 mg/kg, p.o.) but not ORG-52186 significantly attenuated THC-induced catalepsy, it had no significant effect on the enhancement of THC-induced catalepsy by WAY100635 in ddY mice. Conclusions: These findings suggest that V1a receptor regulates THC-induced catalepsy-like immobilization..
8. Shota Yamamoto, Soichiro Ushio, Nobuaki Egashira, takehiro kawashiri, Shohei Mitsuyasu, Hitomi Higuchi, Nana Ozawa, Ken Masuguchi, Yuko Ono, Satohiro Masuda, Excessive spinal glutamate transmission is involved in oxaliplatin-induced mechanical allodynia
A possibility for riluzole as a prophylactic drug, Scientific Reports, 10.1038/s41598-017-08891-1, 7, 1, 9661, 2017.08, Oxaliplatin, a chemotherapy medication, causes severe peripheral neuropathy. Although oxaliplatin-induced peripheral neuropathy is a dose-limiting toxicity, a therapeutic strategy against its effects has not been established. We previously reported the involvement of N-methyl-D-aspartate receptors and their intracellular signalling pathway in oxaliplatin-induced mechanical allodynia in rats. The aim of this study was to clarify the involvement of spinal glutamate transmission in oxaliplatin-induced mechanical allodynia. In vivo spinal microdialysis revealed that the baseline glutamate concentration was elevated in oxaliplatin-treated rats, and that mechanical stimulation of the hind paw markedly increased extracellular glutamate concentration in the same rats. In these rats, the expression of glutamate transporter 1 (GLT-1), which plays a major role in glutamate uptake, was decreased in the spinal cord. Moreover, we explored the potential of pharmacological therapy targeting maintenance of extracellular glutamate homeostasis. The administration of riluzole, an approved drug for amyotrophic lateral sclerosis, suppressed the increase of glutamate concentration, the decrease of GLT-1 expression and the development of mechanical allodynia. These results suggest that oxaliplatin disrupts the extracellular glutamate homeostasis in the spinal cord, which may result in neuropathic symptoms, and support the use of riluzole for prophylaxis of oxaliplatin-induced mechanical allodynia..
9. Moriyama H, Watanabe T, Takasaki K, Nagao M, Kubota K, Katsurabayashi S, Nobuaki Egashira, Iwasaki K, Ameliorative effect of sansoninto on sleep disturbance and spatial memory impairment in an Alzheimer's disease rat model, Trad Kampo Med, DOI: 10.1002/tkm2.1067, 4, 1, 38-45, 2017.04.
10. Shota Yamamoto, Tomohiro Yamashita, Mayu Ito, Jose Manuel Martinez Caaveiro, Nobuaki Egashira, Hidetoshi Saitoh, Tsuda Makoto, New pharmacological effect of fulvestrant to prevent oxaliplatin-induced neurodegeneration and mechanical allodynia in rats, International Journal of Cancer, 10.1002/ijc.32043, 2018.12, Oxaliplatin, which is widely used as chemotherapy for certain solid cancers, frequently causes peripheral neuropathy. Commonly described neuropathic symptoms include aberrant sensations such as mechanical allodynia (hypersensitivity to normally innocuous stimuli). Although oxaliplatin neuropathy is a dose-limiting toxicity, there are no established preventive strategies available at present. By screening several sets of small-molecule chemical libraries (more than 3,000 compounds in total) using a newly established in vitro high-throughput phenotypic assay, we identified fulvestrant, a clinically approved drug for the treatment of breast cancer in postmenopausal women, as having a protective effect on oxaliplatin-induced neuronal damage. Furthermore, histological and behavioural analyses using a rat model of oxaliplatin neuropathy demonstrated the in vivo efficacy of fulvestrant to prevent oxaliplatin-induced axonal degeneration of the sciatic nerve and mechanical allodynia. Furthermore, fulvestrant did not interfere with oxaliplatin-induced cytotoxicity against cancer cells. Thus, our findings reveal a previously unrecognised pharmacological effect of fulvestrant to prevent oxaliplatin-induced painful peripheral neuropathy without impairing its cytotoxicity against cancer cells and may represent a novel prophylactic option for patients receiving oxaliplatin chemotherapy..
11. Yamada T, Kubota T, Yonezawa M, Nishio H, Kanno S, Yano T, Kobayashi D, Nobuaki Egashira, Takada H, Hara T, Masuda S, Evaluation of Teicoplanin Trough Values After the Recommended Loading Dose in Children With Associated Safety Analysis, Pediatr Infect Dis J, 10.1097/INF.0000000000001456, 36, 4, 398-400, 2017.04.
12. Nobuaki Egashira, Iba H, Kuwano H, Kawanaka R, Nagao M, Moriyama H, Watanabe T, Kubota K, Katsurabayashi S, Iwasaki K, Kamishoyosan reduces conditioned fear-induced freezing behavior in socially isolated ovariectomized rats, J Pharmacol Sci, 10.1016/j.jphs.2016.07.007, 131, 4, 279-283, 2016.08.
13. Kuniaki Tsutsumi, Takanori Kaname, Haruka Shiraishi, takehiro kawashiri, Nobuaki Egashira, Polaprezinc reduces paclitaxel-induced peripheral neuropathy in rats without affecting anti-tumor activity, Journal of Pharmacological Sciences, 10.1016/j.jphs.2016.04.019, 131, 2, 146-149, 2016.06, Paclitaxel, an anticancer drug, frequently causes painful peripheral neuropathy. In this study, we investigated the preventive effect of polaprezinc on paclitaxel-induced peripheral neuropathy in rats. Polaprezinc (3 mg/kg, p.o., once daily) inhibited the development of mechanical allodynia induced by paclitaxel (4 mg/kg, i.p., on days 1, 3, 5 and 7) and suppressed the paclitaxel-induced increase in macrophage migration in dorsal root ganglion cells. In addition, polaprezinc did not affect the anti-tumor activity of paclitaxel in cultured cell lines or tumor-bearing mice. These results suggest a clinical indication for polaprezinc in the prevention of paclitaxel-induced neuropathy..
14. Yamada T, Ueda M, Nobuaki Egashira, Zukeyama N, Kuwahara J, Masuda S, Involvement of intracellular cAMP in epirubicin-induced vascular endothelial cell injury, J Pharmacol Sci, 10.1016/j.jphs.2015.12.010, 130, 1, 33-37, 2016.01.
15. Toshikazu Tsuji, Kenichiro Nagata, takehiro kawashiri, Takaaki Yamada, Toshihiro Irisa, Yuko Murakami, Akiko Kanaya, Nobuaki Egashira, Satohiro Masuda, The relationship between occurrence timing of dispensing errors and subsequent danger to patients under the situation according to the classification of drugs by efficacy, Yakugaku Zasshi, 10.1248/yakushi.16-00175, 136, 11, 1573-1584, 2016.01, There are many reports regarding various medical institutions’ attempts at the prevention of dispensing errors. However, the relationship between occurrence timing of dispensing errors and subsequent danger to patients has not been studied under the situation according to the classification of drugs by efficacy. Therefore, we analyzed the relationship between position and time regarding the occurrence of dispensing errors. Furthermore, we investigated the relationship between occurrence timing of them and danger to patients. In this study, dispensing errors and incidents in three categories (drug name errors, drug strength errors, drug count errors) were classified into two groups in terms of its drug efficacy (efficacy similarity (-) group, efficacy similarity (+) group), into three classes in terms of the occurrence timing of dispensing errors (initial phase errors, middle phase errors, final phase errors). Then, the rates of damage shifting from "dispensing errors" to "damage to patients" were compared as an index of danger between two groups and among three classes. Consequently, the rate of damage in "efficacy similarity (-) group" was significantly higher than that in "efficacy similarity (+) group". Furthermore, the rate of damage is the highest in "initial phase errors", the lowest in "final phase errors" among three classes. From the results of this study, it became clear that the earlier the timing of dispensing errors occurs, the more severe the damage to patients becomes..
16. Fujita S, Ushio S, Ozawa N, Masuguchi K, Kawashiri T, Oishi R, Nobuaki Egashira, Exenatide Facilitates Recovery from Oxaliplatin-Induced Peripheral Neuropathy in Rats, PLoS One, 10.1371/journal.pone.0141921, 10, 11, 2015.11.
17. Higuchi H, Yamamoto S, Ushio S, Kawashiri T, Nobuaki Egashira, Goshajinkigan reduces bortezomib-induced mechanical allodynia in rats: Possible involvement of kappa opioid receptor, J Pharmacol Sci, 10.1016/j.jphs.2015.09.004, 129, 3, 196-199, 2015.11.
18. Tsutsumi K, Kaname T, Shiraishi H, Kawashiri T, Nobuaki Egashira, Polaprezinc reduces paclitaxel-induced peripheral neuropathy in rats without affecting anti-tumor activity, J Pharmacol Sci, 10.1016/j.jphs.2015.09.004, 131, 2, 146-149, 2015.11.
19. Yamamoto S, Kawashiri T, Higuchi H, Tsutsumi K, Ushio S, Kaname T, Shirahama M, Nobuaki Egashira, Behavioral and pharmacological characteristics of bortezomib-induced peripheral neuropathy in rats, J Pharmacol Sci, 10.1016/j.jphs.2015.08.006, 129, 1, 43-50, 2015.09.
20. Jun Kuwahara, Takaaki Yamada, Nobuaki Egashira, Mitsuyo Ueda, Nina Zukeyama, Soichiro Ushio, Satohiro Masuda, Comparison of the anti-tumor effects of selective serotonin reuptake inhibitors as well as serotonin and norepinephrine reuptake inhibitors in human hepatocellular carcinoma cells, Biological and Pharmaceutical Bulletin, 10.1248/bpb.b15-00128, 38, 9, 1410-1414, 2015.09, The anti-tumor effects of selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) on several types of cancer cells have been reported. However, comparison of the anti-tumor effects of these drugs on human hepatocellular carcinoma (HepG2) cells has not been studied. We compared the anti-tumor effects of four SSRIs and two SNRIs on HepG2 cells. SSRIs and duloxetine dose-dependently decreased cell viability. Milnacipran had no effect on cell viability. The half-maximal inhibitory concentration was lower in the order of: sertraline, paroxetine, duloxetine, fluvoxamine, escitalopram, and milnacipran. Exposure to sertraline (2 μM) significantly increased caspase-3/7 activity. These results suggest that, of the agents tested here, sertraline had the highest sensitivity to HepG2 cells, and activation of the caspase pathway is involved in the anti-tumor effects of sertraline in HepG2 cells..
21. Hiroaki Ikesue, Hiroyuki Watanabe, Megumi Hirano, Ayako Chikamori, Kimitaka Suetsugu, Yuriko Ryokai, Nobuaki Egashira, Tsuyoshi Yamada, Munehiko Ikeda, Eiji Iwama, Taishi Harada, Koichi Takayama, Yoichi Nakanishi, Satohiro Masuda, Risk factors for predicting severe neutropenia induced by pemetrexed plus carboplatin therapy in patients with advanced non-small cell lung cancer, Biological and Pharmaceutical Bulletin, 10.1248/bpb.b15-00162, 38, 8, 1192-1198, 2015.08, Pemetrexed plus carboplatin therapy is widely administered to patients with non-squamous non-small cell lung cancer. Although severe neutropenia is often observed during this combination therapy, its predictive factors are unknown. Therefore, we investigated the predictive factors for severe neutropenia in 77 patients treated with this combination therapy at the Department of Respiratory Medicine, Kyushu University Hospital, between September 2009 and September 2013. All data were retrospectively collected from the electronic medical record system, and univariate and multivariate logistic regression analyses were performed to identify risk factors for grade 3 or 4 neutropenia. Among the 77 patients, 34 (44%) developed grade 3 or 4 neutropenia. Multivariate analysis revealed that lower baseline hemoglobin values (odds ratio [OR], 1.97 per 1 g/dL decrease; 95% confidence interval [CI], 1.39-2.99, p<0.01) and lower baseline neutrophil counts (OR, 1.71 per 1000/mm3 decrease; 95% CI, 1.14-2.71, p=0.01) were significantly associated with grade 3 or 4 neutropenia. During 4 courses of pemetrexed plus carboplatin therapy, the incidence of grade 3 or 4 neutropenia in patients with baseline hemoglobin values of <11.6 g/dL was significantly higher than that in patients with values of ≥11.6 g/dL [84% (16/19) vs. 31% (18/58), p<0.001]. In conclusion, patients with lower baseline neutrophil counts or lower baseline hemoglobin values, especially those with baseline hemoglobin values of <11.6 g/dL, should be monitored more carefully during pemetrexed plus carboplatin therapy..
22. Tsuji T, Irisa T, Tagawa S, Kawashiri T, Ikesue H, Kokubu C, Kanaya A, Nobuaki Egashira, Masuda S, Differences in recognition of similar medication names between pharmacists and nurses: a retrospective study, J Pharma Health Care Sci, 1, 19, 2015.07.
23. Tsuji T, Irisa T, Ohata S, Kokubu C, Kanaya A, Sueyasu M, Nobuaki Egashira, Masuda S, Relationship between incident types and impact on patients in drug name errors: a correlational study, J Pharma Health Care Sci, 1, 11, 2015.04.
24. Ken Masuguchi, Hitomi Watanabe, takehiro kawashiri, Soichiro Ushio, Nana Ozawa, Haruka Morita, Ryozo Oishi, Nobuaki Egashira, Neurotropin® relieves oxaliplatin-induced neuropathy via Gi protein-coupled receptors in the monoaminergic descending pain inhibitory system, Life Sciences, 10.1016/j.lfs.2013.12.229, 98, 1, 49-54, 2014.03, Aims Oxaliplatin is a key drug in the treatment of colorectal cancer, but it causes acute and chronic peripheral neuropathies. We previously reported that repeated administration of neurotropin prevents oxaliplatin-induced mechanical allodynia by inhibiting axonal degeneration in rats. In the present study, we investigated the analgesic effect of a single administration of neurotropin on oxaliplatin-induced neuropathy in rats. Main methods Oxaliplatin (4 mg/kg) was administered intraperitoneally twice a week for 4 weeks. Cold hyperalgesia was assessed using the acetone test and mechanical allodynia was evaluated using the von Frey test. Key findings Repeated injection of oxaliplatin induced cold hyperalgesia on day 5 and mechanical allodynia on day 28. A single administration of neurotropin transiently relieved both pain behaviors. The analgesic effect of neurotropin was inhibited by pretreatment with 5-HT 1A, 5-HT2, 5-HT3, and α2 receptor antagonists and by monoamine depletion. Moreover, the analgesic effect of neurotropin was abolished by intrathecal injection of pertussis toxin, a G i protein inhibitor. Significance These results suggest that neurotropin is effective in relieving oxaliplatin-induced neuropathy, and that Gi protein-coupled receptors in the monoaminergic descending pain inhibitory system may be involved in the analgesic effect of neurotropin. Neurotropin may have clinical potential for the treatment of oxaliplatin-induced neuropathies..
25. Takaaki Yamada, Toshio Kubota, Masako Nakamura, Masayuki Ochiai, Mahoro Yonezawa, Takahisa Yano, takehiro kawashiri, Nobuaki Egashira, Toshiro Hara, Satohiro Masuda, Evaluation of teicoplanin concentrations and safety analysis in neonates, International Journal of Antimicrobial Agents, 10.1016/j.ijantimicag.2014.07.005, 44, 5, 458-462, 2014.01, The aims of this study were (i) to evaluate the relationship between teicoplanin (TEIC) dosage and subsequent trough concentration, (ii) to investigate factors that affect TEIC serum concentration fluctuations and (iii) to examine the association between serum concentration of TEIC and adverse reactions in neonates. A total of 37 eligible neonates (<28 days of age) treated with TEIC from 2008-2012 were included in this study. The median trough concentration in the loading dose regimen of >12-16 mg/kg on Day 1, followed by >6-8 mg/kg every 24 h (q24 h) was 19.6 μg/mL on Day 3 or 4, and the median trough concentration in the maintenance dose regimen of >6-8 mg/kg q24 h was 18.5 μg/mL at steady-state. There were significant correlations between serum creatinine and concentration/dose (C/D) ratio (r = 0.475, P = 0.019), body weight and C/D ratio (r = -0.425, P = 0.038) and corrected gestational age and C/D ratio (r = -0.482, P = 0.017) after administering the loading dose. The incidence of hepatic dysfunction, renal impairment and thrombocytopenia was 14.8%, 20.0% and 14.8%, respectively. There was no significant difference in the incidence of adverse reactions between the trough concentration <20 μg/mL and ≥20 μg/mL groups. These data suggest that the recommended TEIC dosage for neonates is appropriate to achieve and maintain a trough concentration range of 15-30 μg/mL, and it is possible to set the target trough concentration at ≥20 μg/mL for deep-seated infections such as endocarditis, bone and joint infections, and osteomyelitis..
26. Kuniaki Tsutsumi, Yuji Yamashita, Soichiro Ushio, takehiro kawashiri, Takanori Kaname, Shunsuke Fujita, Ryozo Oishi, Nobuaki Egashira, Oxaliplatin induces hypomyelination and reduced neuregulin 1 expression in the rat sciatic nerve, Neuroscience Research, 10.1016/j.neures.2014.02.004, 80, 1, 86-90, 2014.01, Oxaliplatin causes severe peripheral neuropathy. In this study, we examined hypomyelination in the peripheral nerve in oxaliplatin-induced neuropathy rat model. Gene expression of neuregulin 1 (NRG1), a myelination regulatory factor, is reduced in the dorsal root ganglion (DRG) in DNA microarray analysis. Oxaliplatin increased the g-ratio and reduced levels of myelin protein zero in sciatic nerve, suggesting the hypomyelination. Moreover, oxaliplatin reduced NRG1 mRNA levels in the DRG and decreased levels of cleaved NRG1 type III protein in the sciatic nerve. Our results indicate that oxaliplatin induces hypomyelination and reduced NRG1 expression..
27. Hiroaki Ikesue, Toshikazu Tsuji, Koujiro Hata, Hiroyuki Watanabe, Kazuto Mishima, Mayako Uchida, Nobuaki Egashira, Toshihiro Miyamoto, Eishi Baba, Koichi Akashi, Koichi Takayama, Yoichi Nakanishi, Eriko Tokunaga, Tatsuro Okamoto, Yoshihiko Maehara, Akira Yokomizo, Seiji Naito, Makoto Kubo, Masao Tanaka, Satohiro Masuda, Time Course of Calcium Concentrations and Risk Factors for Hypocalcemia in Patients Receiving Denosumab for the Treatment of Bone Metastases From Cancer, Annals of Pharmacotherapy, 10.1177/1060028014539919, 48, 9, 1159-1165, 2014.01, Background: Severe hypocalcemia sometimes develops during denosumab treatment for bone metastases from cancer and is, therefore, an important issue. However, limited information is available on the risk factors for hypocalcemia and the appropriate interval for monitoring serum calcium concentration. Objective: The present study aimed to identify the risk factors for grade ≥2 hypocalcemia and to investigate the time course of serum calcium concentrations in patients receiving denosumab for bone metastases from cancer. Method: The medical records of 66 cancer patients treated with denosumab between April 2012 and August 2013 were retrospectively reviewed. Result: Of the 66 enrolled patients, 11, 5, and 1 developed grade 1, 2, and 3 hypocalcemia, respectively. All 4 patients with a baseline estimated glomerular filtration rate (eGFR) of <30 mL/min developed hypocalcemia. Hypocalcemia occurred in only 20%, 24%, and 15% of patients with an eGFR of 30 to 59, 60 to 89, and ≥90 mL/min, respectively. Multivariate logistic regression analysis revealed that lower eGFR values (odds ratio, 1.72 per 10 mL/min decrease, P = 0.02) were significantly associated with grade ≥2 hypocalcemia. In 11 patients who developed hypocalcemia during the first treatment course, the mean calcium concentrations decreased from 9.8 mg/dL at baseline to 8.4 mg/dL during the first week and reached a nadir of 8.1 mg/dL during the second week. Conclusion: Our results support more frequent monitoring of serum calcium concentrations at baseline and during the first 2 weeks of treatment in patients receiving denosumab, especially those with an eGFR <30 mL/min..
28. Mayako Uchida, Koji Kato, Hiroaki Ikesue, Kimiko Ichinose, Hiromi Hiraiwa, Asako Sakurai, Tsuyoshi Muta, Katsuto Takenaka, Hiromi Iwasaki, Toshihiro Miyamoto, Takanori Teshima, Motoaki Shiratsuchi, Kimitaka Suetsugu, Kenichiro Nagata, Nobuaki Egashira, Koichi Akashi, Ryozo Oishi, Efficacy and safety of aprepitant in allogeneic hematopoietic stem cell transplantation, Pharmacotherapy, 10.1002/phar.1294, 33, 9, 893-901, 2013.09, STUDY OBJECTIVE To evaluate the efficacy and safety of aprepitant added to standard antiemetic regimens used in high-dose chemotherapy for allogeneic hematopoietic stem cell transplantation (allo- HSCT). DESIGN Retrospective medical record review. SETTING Hematology ward of a university hospital in Japan. PATIENTS Of 88 patients treated with high-dose chemotherapy followed by allo-HSCT, 46 received aprepitant and granisetron as antiemetic therapy (between April 1, 2010, and December 31, 2011), and 42 received granisetron alone (between April 1, 2008, and March 31, 2010). INTERVENTIONS Patients in both groups received 3 mg of granisetron intravenously 30 minutes before the administration of anticancer drugs. In the aprepitant group, 125 mg of aprepitant was administered orally 60-90 minutes before the administration of the first moderately to highly emetogenic anticancer drug. On the following days, 80 mg of aprepitant was administered orally every morning. The mean administration duration of aprepitant was 3.3 days (range 3-6 days). MEASUREMENTS AND MAIN RESULTS The primary objective was to evaluate the percentage of patients who achieved complete response (CR; no vomiting and none to mild nausea). The CR rate in the aprepitant group was significantly higher than that in the control group (48% vs 24%, p=0.02). Multivariate analysis showed that nonprophylactic use of aprepitant was associated with failure to achieve CR (odds ratio [OR] 2.92; 95% confidence interval [CI] 1.13-7.99, p=0.03). The frequency of abdominal pain was lower in the aprepitant group (9% vs 25%, p=0.03). Rates of other frequently observed adverse drug events were similar between groups. There was no significant difference in neutrophil engraftment (median 18 vs 17 days), platelet engraftment (median 32 vs 32 days), the incidence of acute graft-versus-host-disease (63% vs 55%, p=0.52), viral infection (74% vs 67%, p=0.49), or 1-year overall survival (63% vs 62%, p=0.90) between the two groups. CONCLUSIONS The addition of aprepitant to granisetron increases the antiemetic effect without influencing transplantation-related toxicities in allo-HSCT..
29. Naoki Uchida, Kotaro Takasaki, Yuri Sakata, Ai Nogami, Hiroshi Oishi, Takuya Watanabe, Taro Shindo, Nobuaki Egashira, Kaori Kubota, Shutaro Katsurabayashi, Kenichi Mishima, Michihiro Fujiwara, Ryoji Nishimura, Katsunori Iwasaki, Cholinergic involvement and synaptic dynamin 1 expression in yokukansan-mediated improvement of spatial memory in a rat model of early alzheimer's disease, Phytotherapy Research, 10.1002/ptr.4818, 27, 7, 966-972, 2013.07, The aim of this study was to investigate the effect of Yokukansan (YKS) on the impairment of spatial memory and cholinergic involvement in a rat model of early-phase Alzheimer's disease (AD). In this model, rats underwent four-vessel transient cerebral ischemia and then were treated with beta amyloid oligomers injected intracerebroventricularly once daily for 7 days. These animals showed memory impairment in an eight-arm radial maze task without histological evidence of apoptosis but with a decrease in expression of hippocampal dynamin 1, an important factor in synaptic vesicle endocytosis. Oral administration of YKS for 2 weeks significantly increased the number of correct choices and decreased the number of error choices in the eight-arm radial maze task (P < 0.05). Moreover, YKS significantly increased high K+-evoked potentiation of acetylcholine (ACh) release (P < 0.05) and significantly increased the expression of dynamin 1 (P < 0.01) in the hippocampus. The ameliorative effect of YKS on spatial memory impairment in our rat model of early-phase AD may be mediated in part by an increase in ACh release and modulation of dynamin 1 expression, leading to improved synaptic function. Future studies will determine whether YKS is similarly useful in the treatment of memory defects in patients diagnosed with early-stage AD..
30. Mayako Uchida, Hiroaki Ikesue, Toshihiro Miyamoto, Koji Kato, Kimitaka Suetsugu, Kimiko Ichinose, Hiromi Hiraiwa, Asako Sakurai, Katsuto Takenaka, Tsuyoshi Muta, Hiromi Iwasaki, Takanori Teshima, Motoaki Shiratsuchi, Nobuaki Egashira, Koichi Akashi, Ryozo Oishi, Effectiveness and safety of antiemetic aprepitant in japanese patients receiving high-dose chemotherapy prior to autologous hematopoietic stem cell transplantation, Biological and Pharmaceutical Bulletin, 10.1248/bpb.b12-01012, 36, 5, 819-824, 2013.05, For patients receiving high-dose chemotherapy, a 5-hydroxytryptamine 3 receptor antagonist combined with dexamethasone is a standard antiemetic therapy. Despite this prophylactic anti-emetic treatment, many patients still suffer from uncontrollable emesis. In this study, we retrospectively evaluated the antiemetic effectiveness and safety of aprepitant (a neurokinin-1 receptor antagonist) in addition to 5- HT3 antagonist in Japanese patients with hematologic malignancy receiving high-dose chemotherapy prior to autologous peripheral blood stem cell transplantation (auto-PBSCT). Twenty-six patients received aprepitant and granisetron (the aprepitant group), whereas, 22 patients received granisetron alone (the control group). All patients received 3 mg of granisetron intravenously 30 min before chemotherapy administration. Patients in the aprepitant group additionally received 125 mg of aprepitant 60-90 min before administration of the first moderately to highly emetogenic chemotherapy. On the next day or thereafter, 80 mg of aprepitant was administered in the morning until the last administration of moderately to highly emetogenic anticancer drugs. The percentage of patients who achieved complete response (CR), defined as no emesis with only grade 1-2 nausea, in the aprepitant group was significantly higher than that in the control group (42% vs. 5%, p=0.003). Logistic regression analysis showed that non-prophylactic use of aprepitant was significantly associated with non-CR. The frequencies of adverse drug events (ADEs) were not significantly different between two groups. In conclusion, the results of this study suggest that the addition of aprepitant to granisetron can improve the antiemetic effect without increasing ADEs in patients receiving high-dose chemotherapy prior to auto-PBSCT..
31. Hiroyuki Watanabe, Hiroaki Ikesue, Tomoko Tsujikawa, Kenichiro Nagata, Mayako Uchida, Kimitaka Suetsugu, Nobuaki Egashira, Tsuyoshi Muta, Koji Kato, Katsuto Takenaka, Ohga Saiji, Takamitsu Matsushima, Motoaki Shiratsuchi, Toshihiro Miyamoto, Takanori Teshima, Koichi Akashi, Ryozo Oishi, Decrease in venous irritation by adjusting the concentration of injected bendamustine, Biological and Pharmaceutical Bulletin, 10.1248/bpb.b12-00901, 36, 4, 574-578, 2013.04, Intravenous injection of bendamustine often causes venous irritation and also deteriorates the patient's quality of life. Thus, we evaluated the risk factors associated with venous irritation induced by bendamustine in patients with follicular lymphoma or mantle cell lymphoma. We also evaluated the effectiveness of intervention of changing the preparation procedure for bendamustine. All data were retrospectively collected from the electronic medical record system. In the initial analysis of the total 43 courses of bendamustine therapy, most patients (88%) were administered bendamustine with 250 mL of diluent according to the bendamustine package insert in Japan. The median concentration of bendamustine solution (0.56 mg/mL vs. 0.24 mg/mL) and the incidences of venous irritation (66% vs. 0%, p= 0.01) were significantly different between the patients receiving bendamustine at 250 mL and 500 mL of diluent. Based on this result, we proposed changing the final volume of bendamustine dissolution from 250 to 500 mL, which is recommended in other countries. After this intervention, the incidence of venous irritation was significantly reduced from 58 to 20% ( p= 0.02). The incidence of venous irritation increased in a concentration-dependent manner (≤0.40 mg/mL: 6%; 0.41-0.60 mg/mL: 62%, p<0.001; >0.60 mg/mL: 75%, p<0.001). We conclude that a high concentration bendamustine solution is a risk factor for venous irritation and that 500 mL of diluent is ideal. To further reduce the incidence of venous irritation, the concentration of bendamustine solution is recommended to be 0.40 mg/mL or less..
32. Hiroyuki Watanabe, Hiroaki Ikesue, Marina Oshiro, Kenichiro Nagata, Kazuto Mishima, Atsushi Takada, Kimitaka Suetsugu, Masanori Sueyasu, Nobuaki Egashira, Taishi Harada, Koichi Takayama, Yoichi Nakanishi, Ryozo Oishi, Risk factors for predicting severe neutropenia induced by amrubicin in patients with advanced lung cancer, CHEMOTHERAPY, 10.1159/000345617, 58, 6, 419-425, 2013.04, Background: Neutropenia is one of the most frequent and dose-limiting toxicities in amrubicin (AMR) therapy. However, the predictive factors for the development of severe neutropenia in AMR therapy remain unknown. Methods: The subjects were 61 advanced lung cancer patients treated with AMR monotherapy. All data were retrospectively collected from the electronic medical record system. A stepwise logistic regression analysis was performed to identify risk factors for grade 3-4 neutropenia. Results: Of a total 61 patients, 50 were male and 11 were female. The median dose of AMR was 35.0 mg/m2. The incidence of grade 3-4 neutropenia during the first course was 62%. In multivariate analysis, female gender (OR = 6.68; 95% CI 1.01-134.15; p = 0.049), higher AMR doses (40 mg/m2 or more) (OR = 5.98; 95% CI 1.77-23.74; p = 0.003), and lower hematocrit values (OR = 2.04 per 5% decrease; 95% CI 1.04-4.38; p = 0.036) were significantly associated with severe neutropenia induced by AMR. Conclusion: The present results suggest that female gender, higher doses of AMR, and lower baseline hematocrit values are predictive factors associated with severe neutropenia induced by AMR in patients with advanced lung cancer. Patients who have these predictive factors should be monitored carefully and considered for early granulocyte colony-stimulating factor support..
33. Nobuaki Egashira, Moe Abe, Atsunori Shirakawa, Tomiko Niki, Kenichi Mishima, Katsunori Iwasaki, Ryozo Oishi, Michihiro Fujiwara, Effects of mood stabilizers on marble-burying behavior in mice
Involvement of GABAergic system, Psychopharmacology, 10.1007/s00213-012-2904-9, 226, 2, 295-305, 2013.03, Rationale: Obsessive-compulsive disorder (OCD) is characterized by recurrent unwanted thoughts (obsessions), usually accompanied by repetitive behaviors (compulsions) intended to alleviate anxiety. Marble-burying behavior is a pharmacological model for study of OCD. Objectives: In the present study, we examined the effects of mood stabilizers on marble-burying behavior in mice, as well as the role of GABA receptors in this behavior. Methods: The effects of treatment with valproate, carbamazepine, lithium carbonate, lamotrigine, muscimol and baclofen on marble-burying behavior in mice were evaluated. Results: Valproate (10, 30 and 100 mg/kg, i.p.) and carbamazepine (30 and 100 mg/kg, p.o.) significantly reduced marble-burying behavior without affecting total locomotor activity in ICR mice. Lamotrigine (30 mg/kg, i.p.) also significantly reduced marble-burying behavior in ddY mice. On the other hand, lithium carbonate (10, 30 and 100 mg/kg, i.p.) reduced total locomotor activity without affecting marble-burying behavior in ddY mice. The selective GABA A receptor agonist muscimol (1 mg/kg) significantly reduced marble-burying behavior without affecting total locomotor activity, whereas the selective GABAB receptor agonist baclofen (3 mg/kg) reduced total locomotor activity without affecting marble-burying behavior. Moreover, the selective GABAA receptor antagonist bicuculline (3 mg/kg) significantly counteracted the decrease in marble-burying induced by the administration of muscimol (1 mg/kg) and valproate (100 mg/kg). Conclusions: These results suggest that GABAergic mechanism is involved in marble-burying behavior, and that valproate, carbamazepine and lamotrigine reduce marble-burying behavior. Moreover, valproate reduces marble-burying behavior via a GABAA receptor-dependent mechanism..
34. Tatsushima Y, Nobuaki Egashira, Narishige Y, Fukui S, Kawashiri T, Yamauchi Y, Oishi R, Calcium channel blockers reduce oxaliplatin-induced acute neuropathy: A retrospective study of 69 male patients receiving modified FOLFOX6 therapy, BIOMEDICINE & PHARMACOTHERAPY, 10.1016/j.biopha.2012.10.006, 67, 1, 39-42, 2013.02.
35. Uchida M, Ikesue H, Kato K, Ichinose K, Hiraiwa H, Sakurai A, Takenaka K, Iwasaki H, Miyamoto T, Teshima T, Nobuaki Egashira, Akashi K, Oishi R, Antiemetic effectiveness and safety of aprepitant in patients with hematologic malignancy receiving multiday chemotherapy, AMERICAN JOURNAL OF HEALTH-SYSTEM PHARMACY, 10.2146/ajhp120363, 70, 4, 343-349, 2013.02.
36. Morimoto N, Kita S, Shimazawa M, Namimatsu H, Tsuruma K, Hayakawa K, Mishima K, Nobuaki Egashira, Iyoda T, Horie I, Gotoh Y, Iwasaki K, Fujiwara M, Matsuda T, Baba A, Komuro I, Horie K, Takeda J, Iwamoto T, Hara H, Preferential involvement of Na+/Ca2+ exchanger type-1 in the brain damage caused by transient focal cerebral ischemia in mice, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 10.1016/j.bbrc.2012.10.114, 429, 3-4, 186-190, 2012.12.
37. Yamada T, Nonaka T, Yano T, Kubota T, Nobuaki Egashira, Kawashiri T, Oishi R, Simplified dosing regimens of teicoplanin for patient groups stratified by renal function and weight using Monte Carlo simulation, INTERNATIONAL JOURNAL OF ANTIMICROBIAL AGENTS, 10.1016/j.ijantimicag.2012.05.025, 40, 4, 344-348, 2012.10.
38. Yamada T, Nobuaki Egashira, Watanabe H, Nagata K, Yano T, Nonaka T, Oishi R, Decrease in the vinorelbine-induced venous irritation by pharmaceutical intervention, SUPPORTIVE CARE IN CANCER, 10.1007/s00520-011-1244-3, 20, 7, 1549-1553, 2012.07.
39. Soichiro Ushio, Nobuaki Egashira, Hikaru Sada, takehiro kawashiri, Masafumi Shirahama, Ken Masuguchi, Ryozo Oishi, Goshajinkigan reduces oxaliplatin-induced peripheral neuropathy without affecting anti-tumour efficacy in rodents, European Journal of Cancer, 10.1016/j.ejca.2011.08.009, 48, 9, 1407-1413, 2012.06, Oxaliplatin is a key drug in the treatment of colorectal cancer, but it causes acute and chronic neuropathies in patients. Goshajinkigan (GJG) is a Kampo medicine that is used for the treatments of several neurological symptoms including pain and numbness. More recently, GJG has been reported to prevent the oxaliplatin-induced peripheral neuropathy in clinical studies. No experimental study, however, has been conducted to date to determine the effect of GJG on pain behaviour in a rat model of oxaliplatin-induced neuropathy. Moreover, the impact on the anti-tumour effect of oxaliplatin remains unknown. In the present study, we examined the effects of GJG on the peripheral neuropathy and anti-tumour activity of oxaliplatin in rodents. Repeated administration of oxaliplatin caused cold hyperalgesia from days 3 to 37 and mechanical allodynia from days 21 to 28. Repeated administration of GJG prevented the oxaliplatin-induced cold hyperalgesia but not mechanical allodynia and axonal degeneration in rat sciatic nerve. Single administration of GJG reduced both cold hyperalgesia and mechanical allodynia after the development of neuropathy. In addition, GJG did not affect the anti-tumour effect of oxaliplatin in the tumour cells or tumour cells-implanted mice. These results suggest that GJG relieves the oxaliplatin-induced cold hyperalgesia and mechanical allodynia without affecting anti-tumour activity of oxaliplatin, and, therefore, may be useful for the oxaliplatin-induced neuropathy in clinical practice..
40. Nobuaki Egashira, Shirakawa A, Abe M, Niki T, Mishima K, Iwasaki K, Oishi R, Fujiwara M, N-Acetyl-L-Cysteine Inhibits Marble-Burying Behavior in Mice, JOURNAL OF PHARMACOLOGICAL SCIENCES, 10.1254/jphs.11228SC, 119, 1, 97-101, 2012.05.
41. Kenichiro Nagata, Nobuaki Egashira, Takaaki Yamada, Hiroyuki Watanabe, Yui Yamauchi, Ryozo Oishi, Change of formulation decreases venous irritation in breast cancer patients receiving epirubicin, Supportive Care in Cancer, 10.1007/s00520-011-1166-0, 20, 5, 951-955, 2012.05, Purpose Epirubicin is an antitumor drug, particularly used in the treatment of the breast cancer. The peripheral intravenous infusion of epirubicin frequently causes venous irritation such as, erythema, injection site pain, and phlebitis. The purpose of the present study was to investigate the risk factor associated with the epirubicin-induced venous irritation and to establish a suitable administration method of epirubicin. Methods The phlebitis scores (Visual Infusion Phlebitis score) were evaluated retrospectively using the collected nursing record. We analyzed the risk factor associated with venous irritation in 97 patients administered with epirubicin from December 2004 to September 2008. We subsequently changed the regimen of epirubicin and examined the incidence of venous irritation in 26 patients administered with epirubicin from August 2009 to March 2010. Results The phlebitis scores were significantly higher in the patients treated with ready-to-use solution compared with lyophilized powder (P=0.04). Based on this result, we switched the formulation of epirubicin to lyophilized powder. After the intervention, the phlebitis scores were significantly decreased (P=0.003). An ordinal logistic regression analysis revealed that use of ready-to-use solution was a significant predictor for venous irritation (odds ratio=3.70; 95%, confidence intervals, 1.29-11.45; P=0.02). Conclusions The use of ready-to-use solution was a risk factor for epirubicin-induced venous irritation. The change of formulation by pharmacist intervention decreased the risk of venous irritation..
42. Yohei Arimura, Takahisa Yano, Megumi Hirano, Yuya Sakamoto, Nobuaki Egashira, Ryozo Oishi, Mitochondrial superoxide production contributes to vancomycin-induced renal tubular cell apoptosis, Free Radical Biology and Medicine, 10.1016/j.freeradbiomed.2012.02.038, 52, 9, 1865-1873, 2012.05, Vancomycin chloride (VCM), a glycopeptide antibiotic, is widely used for the therapy of infections caused by methicillin-resistant Staphylococcus aureus. However, nephrotoxicity is a major adverse effect in VCM therapy. In this study, we investigated the cellular mechanisms underlying VCM-induced renal tubular cell injury in cultured LLC-PK1 cells. VCM induced a concentration- and time-dependent cell injury in LLC-PK1 cells. VCM caused increases in the numbers of annexin V-positive/PI-negative cells and TUNEL-positive cells, indicating the involvement of apoptotic cell death in VCM-induced renal cell injury. The VCM-induced apoptosis was accompanied by the activation of caspase-9 and caspase-3/7 and reversed by inhibitors of these caspases. Moreover, VCM caused an increase in intracellular reactive oxygen species production and mitochondrial membrane depolarization, which were reversed by vitamin E. In addition, mitochondrial complex I activity was inhibited by VCM as well as by the complex I inhibitor rotenone, and rotenone mimicked the VCM-induced LLC-PK1 cell injury. These findings suggest that VCM causes apoptotic cell death in LLC-PK1 cells by enhancing mitochondrial superoxide production leading to mitochondrial membrane depolarization followed by the caspase activities. Moreover, mitochondrial complex I may play an important role in superoxide production and renal tubular cell apoptosis induced by VCM..
43. Shirahama M, Ushio S, Nobuaki Egashira, Yamamoto S, Sada H, Masuguchi K, Kawashiri T, Oishi R, Inhibition of Ca2+/Calmodulin-dependent protein kinase II reverses oxaliplatin-induced mechanical allodynia in Rats, MOLECULAR PAIN, 10.1186/1744-8069-8-26, 8, 26, 2012.04.
44. Takaaki Yamada, Nobuaki Egashira, Ayami Bando, Yui Nishime, Yuki Tonogai, Maiko Imuta, Takahisa Yano, Ryozo Oishi, Activation of p38 MAPK by oxidative stress underlying epirubicin-induced vascular endothelial cell injury, Free Radical Biology and Medicine, 10.1016/j.freeradbiomed.2012.02.003, 52, 8, 1285-1293, 2012.04, Epirubicin, an anthracycline antitumor drug, often causes vascular injury such as vascular pain, phlebitis, and necrotizing vasculitis. However, an effective prevention for the epirubicin-induced vascular injury has not been established. The purpose of this study is to identify the mechanisms of cell injury induced by epirubicin in porcine aorta endothelial cells (PAECs). PAECs were exposed to epirubicin for 10 min followed by further incubation without epirubicin. The exposure to epirubicin (3-30 μM) decreased the cell viability concentration and time dependently. Epirubicin increased the activity of caspase-3/7, apoptotic cells, and intracellular lipid peroxide levels, and also induced depolarization of mitochondrial membranes. These intracellular events were reversed by glutathione (GSH) and N-acetylcysteine (NAC), while epirubicin rather increased intracellular GSH slightly and l-buthionine-(S,R)-sulfoximine, a specific inhibitor of GSH synthesis, had no effect on the epirubicin-induced cell injury. The epirubicin-induced cell injury and increase of caspase-3/7 activity were also attenuated by p38 mitogen-activated protein kinase (MAPK) inhibitors, SB203580 and PD169316. Moreover, epirubicin significantly enhanced the phosphorylation of p38 MAPK, and these effects were attenuated by GSH and NAC. In contrast, a c-Jun N-terminal kinase inhibitor SP600125, an extracellular signal-regulated kinase inhibitor PD98059, and a p53 inhibitor pifithrin α did not affect the epirubicin-induced cell injury and increase of caspase-3/7 activity. These results indicate that an activation of p38 MAPK by oxidative stress is involved in the epirubicin-induced endothelial cell injury..
45. Nobuaki Egashira, Ryoko Okuno, Atsunori Shirakawa, Masaki Nagao, Kenichi Mishima, Katsunori Iwasaki, Ryozo Oishi, Michihiro Fujiwara, Role of 5-hydroxytryptamine 2C receptors in marble-burying behavior in mice, Biological and Pharmaceutical Bulletin, 10.1248/bpb.35.376, 35, 3, 376-379, 2012.03, We examined the role of 5-hydroxytryptamine 2C (5-HT 2C) receptors in marble-burying behavior in mice. When administered alone, the selective 5-HT 2C agonist WAY161503 (3 mg/kg) inhibited marble-burying behavior. Moreover, the selective 5-HT 2C antagonist SB242084 (3 mg/kg) reversed the inhibition of marble-burying behavior by 2,5-dimethoxy-4-iodoamphetamine (DOI) (1 mg/kg) or WAY161503 (3 mg/kg). Similarly, SB242084 (1 mg/kg) reversed the inhibition of marble-burying behavior by fluvoxamine (30 mg/kg) or paroxetine (3 mg/kg). These results suggest that 5-HT 2C receptors play a role in marble-burying behavior in mice..
46. Nobuaki Egashira, Manome N, Mishima K, Iwasaki K, Oishi R, Fujiwara M, Involvement of opioid system in cognitive deficits induced by Delta(9)-tetrahydrocannabinol in rats, PSYCHOPHARMACOLOGY, 10.1007/s00213-011-2442-x, 219, 4, 1111-1118, 2012.02.
47. takehiro kawashiri, Nobuaki Egashira, Kentaro Kurobe, Kuniaki Tsutsumi, Yuji Yamashita, Soichiro Ushio, Takahisa Yano, Ryozo Oishi, L type Ca 2+ channel blockers prevent oxaliplatin-induced cold hyperalgesia and TRPM8 overexpression in rats, Molecular Pain, 10.1186/1744-8069-8-7, 8, 2012.01, Background: Oxaliplatin is an important drug used in the treatment of colorectal cancer. However, it frequently causes severe acute and chronic peripheral neuropathies. We recently reported that repeated administration of oxaliplatin induced cold hyperalgesia in the early phase and mechanical allodynia in the late phase in rats, and that oxalate derived from oxaliplatin is involved in the cold hyperalgesia. In the present study, we examined the effects of Ca 2+ channel blockers on oxaliplatin-induced cold hyperalgesia in rats.Methods: Cold hyperalgesia was assessed by the acetone test. Oxaliplatin (4 mg/kg), sodium oxalate (1.3 mg/kg) or vehicle was injected i.p. on days 1 and 2. Ca 2+ (diltiazem, nifedipine and ethosuximide) and Na + (mexiletine) channel blockers were administered p.o. simultaneously with oxaliplatin or oxalate on days 1 and 2.Results: Oxaliplatin (4 mg/kg) induced cold hyperalgesia and increased in the transient receptor potential melastatin 8 (TRPM8) mRNA levels in the dorsal root ganglia (DRG). Furthermore, oxalate (1.3 mg/kg) significantly induced the increase in TRPM8 protein in the DRG. Treatment with oxaliplatin and oxalate (500 μM for each) also increased the TRPM8 mRNA levels and induced Ca 2+ influx and nuclear factor of activated T-cell (NFAT) nuclear translocation in cultured DRG cells. These changes induced by oxalate were inhibited by nifedipine, diltiazem and mexiletine. Interestingly, co-administration with nifedipine, diltiazem or mexiletine prevented the oxaliplatin-induced cold hyperalgesia and increase in the TRPM8 mRNA levels in the DRG.Conclusions: These data suggest that the L type Ca 2+ channels/NFAT/TRPM8 pathway is a downstream mediator for oxaliplatin-induced cold hyperalgesia, and that Ca 2+ channel blockers have prophylactic potential for acute neuropathy..
48. Hikaru Sada, Nobuaki Egashira, Soichiro Ushio, takehiro kawashiri, Masafumi Shirahama, Ryozo Oishi, Repeated administration of amitriptyline reduces oxaliplatin-induced mechanical allodynia in rats, Journal of Pharmacological Sciences, 10.1254/jphs.12006SC, 118, 4, 547-551, 2012, Oxaliplatin is a key drug in the treatment of colorectal cancer, but it causes acute and chronic neuropathies in patients. Amitriptyline has widely been used in patients with painful neuropathy. In this study, we investigated the effect of amitriptyline on the oxaliplatin-induced neuropathy in rats. Repeated administration of amitriptyline (5 and 10 mg/kg, p.o., once a day) reduced the oxaliplatin-induced mechanical allodynia but not cold hyperalgesia and reversed the oxaliplatin-induced increase in the expression of NR2B protein and mRNA in rat spinal cord. These results suggest that amitriptyline is useful for the treatment of oxaliplatin-induced neuropathy clinically..
49. Takaaki Yamada, Nobuaki Egashira, Maiko Imuta, Ayami Bando, Takahisa Yano, Mami Saito, Ryozo Oishi, Comparison of injuring effects of vesicant, irritant, and nonvesicant anticancer drugs on endothelial cells, Journal of Pharmacological Sciences, 10.1254/jphs.11070SC, 117, 2, 125-128, 2011.10, Anticancer drugs are classified as vesicant, irritant, and nonvesicant drugs on the basis of frequency of their vascular disorder. In this study, we compared the injuring effects of three typical anticancer drugs of each class on porcine aorta endothelial cells (PAECs). The concentration inducing 50% cell viability inhibition was lower in the order of vesicant, irritant, and nonvesicant drugs. These results suggest that injuring effects of anticancer drugs on PAECs may be relevant as an indicator of frequency of their vascular disorder, and that this experimental model may be useful for the study of vascular disorder..
50. Yuji Yamashita, Nobuaki Egashira, Ken Masuguchi, Soichiro Ushio, takehiro kawashiri, Ryozo Oishi, Comparison of peripheral neuropathy induced by standard and nanoparticle albumin-bound paclitaxel in rats, Journal of Pharmacological Sciences, 10.1254/jphs.11062SC, 117, 2, 116-120, 2011.10, Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) is delivered to tumors and increases antitumor activity compared with solvent-based paclitaxel. However, in a clinical trial, higher and lower rates of peripheral neuropathy and neutropenia were observed. In this study, we compared the effects of nab-paclitaxel and standard paclitaxel on pain behaviors in rats. Repeated administration of nab-paclitaxel dose-dependently induced both mechanical and cold allodynia, and the effects of nab-paclitaxel on pain behaviors tended to be stronger than that of standard paclitaxel at the doses used clinically. These results suggest that closer attention must be paid to the neuropathy when administering nab-paclitaxel in clinical settings..
51. Yoko Tatsushima, Nobuaki Egashira, Naohiro Matsushita, Kentaro Kurobe, takehiro kawashiri, Takahisa Yano, Ryozo Oishi, Pemirolast reduces cisplatin-induced kaolin intake in rats, European Journal of Pharmacology, 10.1016/j.ejphar.2011.04.026, 661, 1-3, 57-62, 2011.07, Emesis is the most feared side effect in patients who are undergoing cancer chemotherapy. In particular, cisplatin causes severe acute and delayed emesis. Although early vomiting is well controlled by 5-hydroxytryptamine 3 (5-HT 3) receptor antagonists, delayed-phase vomiting is not sufficiently controlled. Substance P is thought to be involved in the development of emesis, and tachykinin NK1 receptor antagonists can inhibit delayed vomiting. We previously have reported that substance P is involved in the paclitaxel-induced hypersensitivity reaction in rats, and anti-allergic agent pemirolast reduces these reactions via inhibition of substance P release. In the present study, we investigated the effect of pemirolast on cisplatin-induced kaolin intake, which is an index of nausea/vomiting in the rat. Cisplatin (5 mg/kg, i.p.) induced kaolin intake and reduced normal feed intake from days 1 to 5 after injection. Cisplatin-induced kaolin intake was significantly reduced by co-administration of ondansetron (2 mg/kg, i.p.), a 5-HT3 receptor antagonist, and dexamethasone (2 mg/kg, i.p.) from days 1 to 5. Similarly, pemirolast (10 mg/kg, p.o.) and the tachykinin NK1 receptor antagonist aprepitant (10 and 30 mg/kg, p.o.) significantly reduced cisplatin-induced kaolin intake on days 3 and 4. Moreover, pemirolast at the same dose significantly reversed the cisplatin-induced increase in the cerebrospinal fluid level of substance P in rats. These results suggest that substance P is involved in cisplatin-induced kaolin intake in rats, and pemirolast reduces kaolin intake by inhibition of substance P release..
52. Nobuaki Egashira, Atsunori Shirakawa, Ryoko Okuno, Kenichi Mishima, Katsunori Iwasaki, Ryozo Oishi, Michihiro Fujiwara, Role of endocannabinoid and glutamatergic systems in DOI-induced head-twitch response in mice, Pharmacology Biochemistry and Behavior, 10.1016/j.pbb.2011.04.003, 99, 1, 52-58, 2011.07, We previously reported that systemic administration of the endocannabinoid anandamide inhibited the head-twitches induced by the hallucinogenic drug 2,5-dimethoxy-4-iodoamphetamine (DOI) in mice, which is mediated via the activation of 5-HT 2A receptors. Endocannabinoid and glutamatergic systems have been suggested to modulate the function of 5-HT 2A receptors. In the present study, we further investigated the role of endocannabinoid and glutamatergic systems in DOI-induced head-twitch response in mice. An anandamide transport inhibitor AM404 (0.3-3 mg/kg, i.p.), a fatty acid amide hydrolase inhibitor URB597 (0.1-10 mg/kg, i.p.), a glutamate release inhibitor riluzole (0.3 and 1 mg/kg, i.p.), a natural glutamate analog l-glutamylethylamide (theanine, 1 and 3 mg/kg, p.o.) and an α-amino-3- hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor antagonist NBQX (0.01-0.3 mg/kg, i.p.) significantly inhibited DOI-induced head-twitch response. The AMPA receptor positive modulator aniracetam (30 or 100 mg/kg, p.o.) reversed inhibition of head-twitch response by NBQX and URB597. These findings indicated that endocannabinoid and glutamatergic systems participate in the mechanism of action of DOI to induce head-twitch response..
53. Nobuaki Egashira, Ai Nogami, Katsunori Iwasaki, Ayumi Ishibashi, Naoki Uchida, Kotaro Takasaki, Kenichi Mishima, Ryoji Nishimura, Ryozo Oishi, Michihiro Fujiwara, Yokukansan enhances pentobarbital-induced sleep in socially isolated mice
Possible involvement of GABA A - Benzodiazepine receptor complex, Journal of Pharmacological Sciences, 10.1254/jphs.11079SC, 116, 3, 316-320, 2011.07, In the present study, we investigated the effect of the Kampo medicine Yokukansan (YKS) on pentobarbital-induced sleep in group-housed and socially isolated mice. Socially isolated mice showed shorter sleeping time than the group-housed mice. YKS (300 mg/kg, p.o.) prolonged the pentobarbital-induced sleeping time in socially isolated mice without affecting pentobarbital sleep in group-housed mice. The prolongation of sleeping time by YKS was reversed by bicuculline (3 mg/kg, i.p.) and flumazenil (3 mg/kg, i.p.), but not WAY100635. These findings suggest that the GABA A - benzodiazepine receptor complex, but not 5-HT 1A receptors, is involved in the reversal effect of YKS on the decrease of pentobarbital sleep by social isolation..
54. Yoko Tatsushima, Nobuaki Egashira, takehiro kawashiri, Yuki Mihara, Takahisa Yano, Kazuto Mishima, Ryozo Oishi, Involvement of substance P in peripheral neuropathy induced by paclitaxel but not oxaliplatin, Journal of Pharmacology and Experimental Therapeutics, 10.1124/jpet.110.175976, 337, 1, 226-235, 2011.04, The painful peripheral neuropathy occurring frequently during chemotherapy with paclitaxel or oxaliplatin is one of their dose-limiting factors. We reported previously that substance P is involved in the pathogenesis of pulmonary hypersensitivity reaction to paclitaxel in rats, and an antiallergic agent pemirolast reverses this reaction via the blockade of release of substance P. In the present study, we investigated the involvement of substance P in paclitaxel-induced peripheral neuropathy compared with that by oxaliplatin. In von Frey and acetone tests in rats repeated administration of paclitaxel (6 mg/kg i.p., once a week for 4 weeks) or oxaliplatin (4 mg/kg i.p., twice a week for 4 weeks) induced both mechanical allodynia and cold hyperalgesia. Paclitaxel-induced peripheral neuropathy was reversed primarily by the acute administration of pemirolast (0.1 and 1 mg/kg p.o.). Moreover, coadministration of the receptor antagonists neurokinin 1 [N-acetyl-L-tryptophan 3,5-bis(trifluoromethyl)benzylester (L-732,138), 100 μg/body i.t.] and neurokinin 2 [5-fluoro-3-[2-[4-methoxy-4-[[(R)-phenylsulphinyl]-methyl]-1- piperidinyl]ethyl]-1H-indole (GR159897), 100 μg/body i.t.] strongly reversed paclitaxel-induced neuropathy. On the other hand, oxaliplatin-induced peripheral neuropathy was not reversed by pemirolast. In the in vitro study using cultured adult rat dorsal root ganglion neurons paclitaxel (1000 ng/ml) significantly increased the release of substance P, and pemirolast (100 and 1000 nM) significantly inhibited this increase of substance P release. Oxaliplatin, by contrast, did not increase the release of substance P. These results suggest that substance P is involved in paclitaxel-induced neuropathy, and the mechanism of its action is clearly different from that of oxaliplatin..
55. takehiro kawashiri, Nobuaki Egashira, Hitomi Watanabe, Yoko Ikegami, Shingo Hirakawa, Yuki Mihara, Takahisa Yano, Hiroaki Ikesue, Ryozo Oishi, Prevention of oxaliplatin-induced mechanical allodynia and neurodegeneration by neurotropin in the rat model, European Journal of Pain, 10.1016/j.ejpain.2010.08.006, 15, 4, 344-350, 2011.04, Oxaliplatin is a key drug for colorectal cancer, but it causes acute peripheral neuropathy (triggered by cold) and chronic neuropathy (sensory and motor neuropathy) in patients. Neurotropin, a non-protein extract from the inflamed rabbit skin inoculated with vaccinia virus, has been used to treat various chronic pains. In the present study, we investigated the effect of neurotropin on the oxaliplatin-induced neuropathy in rats. Repeated administration of oxaliplatin caused cold hyperalgesia from Day 5 to Day 29 and mechanical allodynia from Day 15 to Day 47. Repeated administration of neurotropin relieved the oxaliplatin-induced mechanical allodynia but not cold hyperalgesia, and inhibited the oxaliplatin-induced axonal degeneration in rat sciatic nerve. Neurotropin also inhibited the oxaliplatin-induced neurite degeneration in cultured pheochromocytoma 12 (PC12) and rat dorsal root ganglion (DRG) cells. On the other hand, neurotropin did not affect the oxaliplatin-induced cell injury in rat DRG cells. These results suggest that repeated administration of neurotropin relieves the oxaliplatin-induced mechanical allodynia by inhibiting the axonal degeneration and it is useful for the treatment of oxaliplatin-induced neuropathy clinically..
56. Yuki Mihara, Nobuaki Egashira, Hikaru Sada, takehiro kawashiri, Soichiro Ushio, Takahisa Yano, Hiroaki Ikesue, Ryozo Oishi, Involvement of spinal NR2B-containing NMDA receptors in oxaliplatin-induced mechanical allodynia in rats, Molecular Pain, 10.1186/1744-8069-7-8, 7, 2011.01, Background: Oxaliplatin is a platinum-based chemotherapy drug characterized by the development of acute and chronic peripheral neuropathies. The chronic neuropathy is a dose-limiting toxicity. We previously reported that repeated administration of oxaliplatin induced cold hyperalgesia in the early phase and mechanical allodynia in the late phase in rats. In the present study, we investigated the involvement of NR2B-containing N-methyl-D-aspartate (NMDA) receptors in oxaliplatin-induced mechanical allodynia in rats.Results: Repeated administration of oxaliplatin (4 mg/kg, i.p., twice a week) caused mechanical allodynia in the fourth week, which was reversed by intrathecal injection of MK-801 (10 nmol) and memantine (1 μmol), NMDA receptor antagonists. Similarly, selective NR2B antagonists Ro25-6981 (300 nmol, i.t.) and ifenprodil (50 mg/kg, p.o.) significantly attenuated the oxaliplatin-induced pain behavior. In addition, the expression of NR2B protein and mRNA in the rat spinal cord was increased by oxaliplatin on Day 25 (late phase) but not on Day 5 (early phase). Moreover, we examined the involvement of nitric oxide synthase (NOS) as a downstream target of NMDA receptor. L-NAME, a non-selective NOS inhibitor, and 7-nitroindazole, a neuronal NOS (nNOS) inhibitor, significantly suppressed the oxaliplatin-induced pain behavior. The intensity of NADPH diaphorase staining, a histochemical marker for NOS, in the superficial layer of spinal dorsal horn was obviously increased by oxaliplatin, and this increased intensity was reversed by intrathecal injection of Ro25-6981.Conclusion: These results indicated that spinal NR2B-containing NMDA receptors are involved in the oxaliplatin-induced mechanical allodynia..
57. Takaaki Yamada, Hiroyuki Watanabe, Takahisa Yano, Toshiharu Nonaka, Atsushi Takada, Masanobu Sonoda, Toshio Kubota, Nobuaki Egashira, Ryozo Oishi, The timing of expression of blood coagulation abnormality in patients treated with warfarin and S-1 concomitantly, Yakugaku Zasshi, 10.1248/yakushi.130.955, 130, 7, 955-960, 2010.07, Although S-1 is frequently used in cancer chemotherapy, the drug interaction with warfarin, an anticoagulant agent, is not fully paid attention. In the present study, we investigated retrospectively the timing of expression of blood coagulation abnormality in nine patients treated with warfarin and S-1 concomitantly. In five patients, the dose of warfarin was reduced or interrupted after concomitant use of S-1. The International Normalized Ratio (INR) was significantly increased after combination with S-1 compared with the former value. In all patients, the INR was increased in three weeks after combination with S-1. On the other hand, serum creatinine, aspartate aminotransferase, alanine aminotransferase or serum albumin was not different before and after combination with S-1. These results suggest that the careful monitoring of the blood coagulation ability is necessary in all patients receiving warfarin and S-1 concomitantly..
58. Mai Hazekawa, Aiko Kataoka, Kazuhide Hayakawa, Takeshi Uchimasu, Riyo Furuta, Keiichi Irie, Yoshiharu Akitake, Miyako Yoshida, Toshihiro Fujioka, Nobuaki Egashira, Ryozo Oishi, Kenji Mishima, Kenichi Mishima, Takahiro Uchida, Katunori Iwasaki, Michihiro Fujiwara, Neuroprotective effect of repeated treatment with Hericium erinaceum in mice subjected to middle cerebral artery occlusion, Journal of Health Science, 10.1248/jhs.56.296, 56, 3, 296-303, 2010.06, The neuroprotective effects of Hericium erinaceum (H. erinaceum) were studied in mice subjected to middle cerebral artery (MCA) occlusion. Infarct volumes were markedly reduced in mice receiving 14 days of H. erinaceum (300mg/kg) treatment prior to 4-hr MCA occlusion. Moreover, 14-day pre-ischemic H. erinaceum treatment significantly increased the levels of nerve growth factor (NGF) in both the cortex and striatum of mice subjected to 4-hr MCA occlusion. However, pre-ischemic H erinaceum treatment had no effect on cerebral blood flow (CBF) in the cortex of mice subjected to MCA occlusion. Treatment with H. erinaceum for 1 day prior to MCA occlusion-induced ischemia had no effect on infarct volume or NGF level. These results suggest that 14 days of treatment with H. erinaceum prior to MCA occlusion protected against focal cerebral ischemia, by increasing NGF levels. This implies that H erinaceum and its components could be useful for preventing cerebral infarction..
59. Nobuaki Egashira, Emi Koushi, Ryoko Okuno, Atsunori Shirakawa, Kenichi Mishima, Katsunori Iwasaki, Ryozo Oishi, Michihiro Fujiwara, Depression-like behavior and reduced plasma testosterone levels in the senescence-accelerated mouse, Behavioural Brain Research, 10.1016/j.bbr.2010.01.030, 209, 1, 142-147, 2010.05, During aging, levels of testosterone gradually decline in men and low levels of testosterone in aged men are accompanied by increased incidence of depressive disorders. The senescence-accelerated-prone mouse 10 (SAMP10) is well known as an animal model of aging. The purpose of this study was to investigate the motor function, anxiety levels, depression-related emotional responses, attentional function and plasma levels of testosterone and dehydroepiandrosterone (DHEA) in SAMP10. SAMP10 exhibited a significant prolongation of immobility time compared to that of the aged-matched control senescence-accelerated-resistant mouse 1 (SAMR1) in the tail suspension test for measuring depression. Moreover, significant low levels of plasma testosterone but not DHEA were found in SAMP10, and the testosterone levels were inversely correlated with the depression-like behavior. By contrast, we did not observe any significant differences between SAMP10 and SAMR1 in the open-field, rota-rod, elevated plus-maze, marble-burying behavior, or prepulse inhibition test. The results of the present study indicate that testosterone may play an important role in the depression-like behavior in SAMP10..
60. Pu F, Kaneko T, Enoki M, Irie K, Okamoto T, Sei Y, Nobuaki Egashira, Oishi R, Mishima K, Kamimura H, Iwasaki K, Fujiwara M, Ameliorating effects of Kangen-karyu on neuronal damage in rats subjected to repeated cerebral ischemia, JOURNAL OF NATURAL MEDICINES, 10.1007/s11418-010-0392-y, 64, 2, 167-174, 2010.04.
61. Nobuaki Egashira, Shingo Hirakawa, takehiro kawashiri, Takahisa Yano, Hiroaki Ikesue, Ryozo Oishi, Mexiletine reverses Oxaliplatin-Induced neuropathic pain in rats, Journal of Pharmacological Sciences, 10.1254/jphs.10012SC, 112, 4, 473-476, 2010.04, Oxaliplatin is a platinum-based chemotherapy drug characterized by the development of acute and chronic peripheral neuropathies. Mexiletine, an orally available Na+-channel blocker, has widely been used in patients with chronic painful diabetic neuropathy. In the present study, we examined the effect of mexiletine on oxaliplatin-induced neuropathic pain in rats. Mexiletine (100, but not 10 and 30, mg/kg, p.o.) completely reversed both mechanical allodynia and cold hyperalgesia induced by oxaliplatin (4 mg/kg, i.p., twice a week). Lidocaine (30, but not 3 and 10, mg/kg, i.p.) also significantly relieved both pain behaviors. These results suggest that mexiletine may be effective in relieving the oxaliplatin-induced neuropathic pain clinically..
62. Tajima O, Nobuaki Egashira, Ohmi Y, Fukue Y, Mishima K, Iwasaki K, Fujiwara M, Sugiura Y, Furukawa K, Furukawa K, Dysfunction of muscarinic acetylcholine receptors as a substantial basis for progressive neurological deterioration in GM3-only mice, BEHAVIOURAL BRAIN RESEARCH, 10.1016/j.bbr.2009.09.005, 206, 1, 101-108, 2010.01.
63. Asuka Maeda, Takahisa Yano, Yoshinori Itoh, Midori Kakumori, Toshio Kubota, Nobuaki Egashira, Ryozo Oishi, Down-regulation of RhoA is involved in the cytotoxic action of lipophilic statins in HepG2 cells, Atherosclerosis, 10.1016/j.atherosclerosis.2009.07.033, 208, 1, 112-118, 2010.01, Objective: Hepatotoxicity is one of the major complaints that occur during lipid-lowering therapy with 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitors, known as statins. We reported earlier that lipophilic but not hydrophilic statins induce apoptosis through inhibition of mevalonate biosynthesis cascade in Chang liver cells. The present study was designed to determine the role for small G protein RhoA in the hepatocytotoxicity of statins. Methods: Statin-induced hepatocytotoxicity in HepG2 cells were assessed by WST-8 cell viability assay, JC-1 mitochondrial membrane potential assay and caspase-3/7 activity assay. Cytosolic RhoA was detected by Western blotting and RhoA activation was measured by ELISA. Results: The lipophilic atorvastatin but not the hydrophilic pravastatin induced the mitochondrial membrane depolarization and the activation of caspase-3/7, which led to cell injury. Supplementation of mevalonate or geranylgeranyl pyrophosphate (GGPP) but not farnesyl pyrophosphate (FPP) reversed these cellular events and cell death induced by atorvastatin. Atorvastatin induced a translocation of RhoA protein into the cytosol and inhibited the activity of the protein. In addition, atorvastatin reduced mitochondrial membrane potential, which was mimicked by GGTase inhibitor GGTI-2147 or the specific RhoA inhibitor such as toxin B and C3 exoenzyme. However, only a few cells revealed mitochondrial membrane depolarization and a loss of viability after exposure to the Rho-kinase inhibitors such as Y-27632 and hydroxy fasudil. Conclusions: RhoA inactivation and to a lesser extent Rho-kinase inhibition after depletion of GGPP is implicated in the etiology of mitochondrial membrane depolarization and subsequent caspase-dependent cell death induced by the lipophilic statin in HepG2 cells..
64. Takaaki Yamada, Nobuaki Egashira, Maiko Imuta, Takahisa Yano, Yui Yamauchi, Hiroyuki Watanabe, Ryozo Oishi, Role of oxidative stress in vinorelbine-induced vascular endothelial cell injury, Free Radical Biology and Medicine, 10.1016/j.freeradbiomed.2009.10.032, 48, 1, 120-127, 2010.01, Vinorelbine (VNR), a vinca alkaloid anticancer drug, often causes vascular injury such as venous irritation, vascular pain, phlebitis, and necrotizing vasculitis. The purpose of this study was to identify the mechanisms that mediate the cell injury induced by VNR in porcine aorta endothelial cells (PAECs). PAECs were exposed to VNR for 10 min followed by further incubation in serum-free medium without VNR. The exposure to VNR (0.3-30 μM) decreased the cell viability concentration and time dependently. The incidence of apoptotic cells significantly increased at 12 h after transient exposure to VNR. At the same time, VNR increased the activity of caspases. Interestingly, VNR rapidly depleted intracellular glutathione (GSH) and increased intracellular reactive oxygen species (ROS) production. Moreover, VNR depolarized the mitochondrial membrane potential and decreased cellular ATP levels. These VNR-induced cell abnormalities were almost completely inhibited by GSH and N-acetylcysteine. On the other hand, l-buthionine-(S,R)-sulfoximine, a specific inhibitor of GSH synthesis, aggravated the VNR-induced loss of cell viability. These results clearly demonstrate that VNR induces oxidative stress by depleting intracellular GSH and increasing ROS production in PAECs, and oxidative stress plays an important role in the VNR-induced cell injury..
65. Kazunori Sano, Emi Koushi, Keiichi Irie, Sei Higuchi, Ryota Tsuchihashi, Junei Kinjo, Nobuaki Egashira, Ryozo Oishi, Naoki Uchida, Hiroshi Nagai, Ryoji Nishimura, Hiroyuki Tanaka, Satoshi Morimoto, Kenichi Mishima, Katsunori Iwasaki, Michihiro Fujiwara, Delta(9)-tetrahydrocannabinol enhances an increase of plasma corticosterone levels induced by forced swim-stress, Biological and Pharmaceutical Bulletin, 10.1248/bpb.32.2065, 32, 12, 2065-2067, 2009.12, The present study was designed to determine the effect of delta(9)-tetrahydrocannabinol (THC) on susceptibility to stress. We reported that THC significantly prolonged the immobility time during the forced swim-stress. The selective cannabinoid CB1 receptor antagonist O-2050 significantly reduced the enhancement of immobility by THC. We investigated the effect of THC on levels of stress hormone corticosterone under non-stress and forced swim-stress conditions. THC did not affect plasma corticosterone levels under non-stress conditions. However, THC, together with forced swim-stress, significantly increased plasma corticosterone levels. This effect was inhibited by O-2050. This evidence suggests that THC, under stressful conditions, enhances the susceptibility of the hypothalamus-pituitary-adrenal-axis to stress via the CB
1
receptor, thereby increasing the risk of depression..
66. Mariko Sakurai, Nobuaki Egashira, takehiro kawashiri, Takahisa Yano, Hiroaki Ikesue, Ryozo Oishi, Oxaliplatin-induced neuropathy in the rat
Involvement of oxalate in cold hyperalgesia but not mechanical allodynia, Pain, 10.1016/j.pain.2009.09.003, 147, 1-3, 165-174, 2009.12, Oxaliplatin is a key drug in the treatment of advanced metastatic colorectal cancer, but it causes acute peripheral neuropathy (acral paresthesias triggered by exposure to cold) and chronic neuropathy (abnormal of sensory and motor dysfunction). Oxaliplatin is metabolized to oxalate and dichloro(1,2-diaminocyclohexane)platinum (Pt(dach)Cl2). Although the chelating of Ca2+ with oxalate eliminated from oxaliplatin is thought as one of the reasons for the neuropathy, there is little behavioral evidence. In this study, we investigated the involvement of oxalate in the oxaliplatin-induced peripheral neuropathy in rats. Oxaliplatin (4 mg/kg, i.p., twice a week) induced cold hyperalgesia/allodynia (cold-plate and acetone tests) in the early phase, and mechanical allodynia (von Frey test) in the late phase. Oxalate (1.3 mg/kg, i.p., twice a week) induced the cold hyperalgesia/allodynia in the early phase, but did not induce the mechanical allodynia. On the other hand, Pt(dach)Cl2 (3.8 mg/kg, i.p., twice a week) induced the mechanical allodynia in the late phase, but did not induce the cold hyperalgesia/allodynia. The pre-administration of calcium or magnesium (0.5 mmol/kg, i.v.) before oxaliplatin or oxalate prevented the cold hyperalgesia but not mechanical allodynia. However, the treatment with calcium or magnesium after the development of neuropathy could not attenuate the cold hyperalgesia or mechanical allodynia. These findings suggest the involvement of oxalate in oxaliplatin-induced cold hyperalgesia but not mechanical allodynia, and usefulness of prophylactic treatments with calcium and magnesium on the acute peripheral neuropathy..
67. Fengling Pu, Kyoko Motohashi, Tomohiro Kaneko, Yurika Tanaka, Naomi Manome, Keiichi Irie, Jirou Takata, Nobuaki Egashira, Ryozo Oishi, Takuya Okamoto, Yasuo Sei, Takako Yokozawa, Kenichi Mishima, Katsunori Iwasaki, Michihiro Fujiwara, Neuroprotective effects of kangen-karyu on spatial memory impairment in an 8-arm radial maze and neuronal death in the hippocampal ca1 region induced by repeated cerebral ischemia in rats, Journal of Pharmacological Sciences, 10.1254/jphs.08245FP, 109, 3, 424-430, 2009.06, In the present study, we investigated the neuroprotective effects of Kangen-karyu (KGK) in a repeated cerebral ischemia model (2 x 10 min, 1-h interval). A 21-day pre- and post- ischemic treatment with KGK (10-300mg/kg) and aspirin (5mg/kg) improved the spatial memory impairment and neuronal death in the hippocampal CA1 region induced by repeated cerebral ischemia. However, a 7-day post-ischemic treatment with KGK did not attenuate the spatial memory impairment and neuronal death in this model. To determine the mechanism of action of KGK, we investigated the effects of a 14-day pre-ischemic treatment with KGK on cerebral blood flow in the hippocampal area of the repeated cerebral ischemia model using laser Doppler flowmetry. The 14-day pre-ischemic treatment with KGK increased the cerebral blood flow during reperfusion. These results suggest that a 21-day pre- and post-ischemic treatment with KGK can protect against brain damage caused by cerebral ischemia by increasing the cerebral blood flow in the hippocampal area..
68. Yano Takahisatyano, Itoh Yoshinori, Kawamura Eiko, Maeda Asuka, Nobuaki Egashira, Motohiro Nishida, Hitoshi Kurose, Oishi Ryozo, Amphotericin B-induced renal tubular cell injury is mediated by Na+ influx through ion-permeable pores and subsequent activation of mitogen-activated protein kinases and elevation of intracellular Ca2+ concentration, Antimicrobial Agents and Chemotherapy, 10.1128/AAC.01137-08, 53, 4, 1420-1426, 2009.04, Amphotericin B (AMB) is one of the most effective antifungal agents; however, its use is often limited by the occurrence of adverse events, especially nephrotoxicity. The present study was designed to determine the possible mechanisms underlying the nephrotoxic action of AMB. The exposure of a porcine proximal renal tubular cell line (LLC-PKl cells) to AMB caused cell injury, as assessed by mitochondrial enzyme activity, the leakage of lactate dehydrogenase, and tissue ATP depletion. Propldium iodide uptake was enhanced, while terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling was not affected by AMB, suggesting a lack of involvement of apoptosis in AMB-induced cell injury. The cell injury was inhibited by the depletion of membrane cholesterol with methyl-ß-cyclodextrin, which lowered the extracellular Na+ concentration or the chelation of intracellular Ca. The rise in the intracellular Ca2+ concentration may be mediated through the activation of the ryanodine receptor (RyR) on the endoplasmic reticulum and the mitochondrial Na+-Ca2+ exchanger, since cell injury was attenuated by dantrolene (an RyR antagonist) and CGP37157 (an Na+-Ca exchanger inhibitor). Moreover, AMB-induced cell injury was reversed by PD169316 (a p38 mitogen-activated protein [MAP] kinase inhibitor), c-Jun N-terminal kinase inhibitor II, and PD98059 (a MEK1/2 inhibitor). The phosphorylations of these MAP kinases were enhanced by AMB in a calcium-independent manner, suggesting the involvement of MAP kinases in AMB-induced cell injury. These findings suggest that Na+ entry through membrane pores formed by the association of AMB with membrane cholesterol leads to the activation of MAP kinases and the elevation of the intracellular Ca2+concentration, leading to renal tubular cell injury..
69. Orie Tajima, Nobuaki Egashira, Yuhsuke Ohmi, Yoshihiko Fukue, Kenichi Mishima, Katsunori Iwasaki, Michihiro Fujiwara, Jinichi Inokuchi, Yasuo Sugiura, Keiko Furukawa, Koichi Furukawa, Reduced motor and sensory functions and emotional response in GM3-only mice
Emergence from early stage of life and exacerbation with aging, Behavioural Brain Research, 10.1016/j.bbr.2008.10.024, 198, 1, 74-82, 2009.03, Sialic acid-containing glycosphingolipids (gangliosides) have been believed to play a role in the regulation and protection of nervous tissues. To clarify their function in the nervous system in vivo, double knockout (DKO) mice of GM2/GD2 synthase and GD3 synthase genes were generated and abnormal behaviors were analyzed. Mutant mice exhibited reduced weight and a round shape of the whole brain that progressively emerged with aging, and displayed motor dysfunction in the footprint, traction, open-field, and 24 h locomotion activity tests. Sensory functions were also reduced in the von Frey and hot plate tests and greatly reduced in the acoustic startle response test. For emotional behavior, fear response was clearly decreased. Numerous neuronal dysfunctions were found even in younger mutant mice examined at 10-23 weeks after birth, which were exacerbated with aging. These results suggest that a lack of gangliosides other than GM3 induces severe neuronal degeneration in the early stage of life, and that the expression of complex gangliosides is essential to maintain the integrity of the nervous system throughout life..
70. Naoki Uchida, Nobuaki Egashira, Katsunori Iwasaki, Ayumi Ishibashi, Ryosuke Tashiro, Ai Nogami, Naomi Manome, Moe Abe, Kotaro Takasaki, Kenichi Mishima, Jiro Takata, Ryozo Oishi, Ryoji Nishimura, Michihiro Fujiwara, Yokukansan inhibits social isolation-induced aggression and methamphetamine-induced hyperlocomotion in rodents, Biological and Pharmaceutical Bulletin, 10.1248/bpb.32.372, 32, 3, 372-375, 2009.03, Behavioral and psychological symptoms of dementia (BPSD) are commonly seen in patients with Alzheimer's disease (AD) and other forms of senile dementia. BPSD have a serious impact on the quality of life of dementia patients, as well as on that of their caregivers. However, effective drug therapy for BPSD has not been established. Recently, the traditional Japanese medicine Yokukansan (YKS, Yi-gan san in Chinese) has been reported to improve BPSD, such as aggression, agitation, irritability, and hallucinations, in a randomized, single-blind, placebo-controlled study. However, the psychopharmacologic effects of YKS remain unexplored. In the present study, we investigated the effects of YKS on social isolation-induced aggressive behavior and methamphetamine- or MK-801-induced hyperlocomotion in rodents. Social isolation markedly induced aggressive behavior in male Wistar rats. Quetiapine at a dose of 10 mg/kg (per os (p.o.)) significantly inhibited this social isolation-induced aggressive behavior. YKS (100, 300 mg/kg, p.o.) also significantly inhibited the aggressive behavior. Moreover, risperidone (0.1 mg/kg, p.o.) significantly inhibited methamphetamine- or MK-801-induced hyperlocomotion in mice. YKS (300 mg/kg, p.o.) inhibited methamphetamine-induced hyperlocomotion, while YKS at the same dose had no effect on MK-801-induced hyperlocomotion. These findings suggest that YKS may be useful for the treatment of aggression and agitation, and that the psychopharmacologic effects of YKS might be mediated, in part, by inhibiting the activity of the dopaminergic system..
71. Takuya Watanabe, Norito Yamagata, Kotaro Takasaki, Kazunori Sano, Kazuhide Hayakawa, Shutaro Katsurabayashi, Nobuaki Egashira, Kenichi Mishima, Katsunori Iwasaki, Michihiro Fujiwara, Decreased acetylcholine release is correlated to memory impairment in the Tg2576 transgenic mouse model of Alzheimer's disease, Brain Research, 10.1016/j.brainres.2008.10.029, 1249, 222-228, 2009.01, Acetylcholine (ACh) release is one of the key factors in memory mechanisms. To clarify whether beta-amyloid (Aβ) induces a disturbance of the cholinergic system leading to memory impairment, we examined memory impairment and measured hippocampal ACh release in Tg2576 (Tg) mice that over-express the Swedish mutant amyloid precursor protein (APPsw). Furthermore, we examined Aβ burden with aging. Tg mice aged 9-11 months, but not aged 4-6 months, showed memory impairment in the 8-arm radial maze behavior test. Spontaneous ACh release was not altered in Tg mice compared with age-matched control mice at 4-6 or 9-11 months of age. On the other hand, high-K+-evoked ACh release was decreased in Tg mice aged 9-11 months, but not in Tg mice aged 4-6 months. Hippocampal Aβ increased in an age-dependent manner, but evident amyloid plaques were not found in the hippocampus of Tg mice aged 11 months. These results suggest that memory impairment in Tg mice could be attributed to cholinergic synapse dysfunction that could not be caused predominantly by amyloid plaques. Measuring ACh release in this model might be a useful index for the screening of new drugs to treat the early-phase of Alzheimer's disease..
72. takehiro kawashiri, Nobuaki Egashira, Yoshinori Itoh, Takao Shimazoe, Yoko Ikegami, Takahisa Yano, Megumu Yoshimura, Ryozo Oishi, Neurotropin reverses paclitaxel-induced neuropathy without affecting anti-tumour efficacy, European Journal of Cancer, 10.1016/j.ejca.2008.10.004, 45, 1, 154-163, 2009.01, Paclitaxel is a commonly used anticancer drug, but it frequently causes peripheral neuropathy. Neurotropin, a non-protein extract from inflamed rabbit skin inoculated with vaccinia virus, has been used to treat various chronic painful conditions. In the present study, we investigated the effect of neurotropin on the paclitaxel-induced neuropathy in rats. Repeated administration of paclitaxel induced mechanical allodynia, cold hyperalgesia, and motor dysfunction. These neuropathies were mostly reversed by the repeated administration of neurotropin. Furthermore, neurotropin ameliorated the paclitaxel-induced axonal degeneration in cultured PC12 and rat dorsal root ganglion cells, and in rat sciatic nerve. In addition, neurotropin did not affect the microtubule aggregation or anti-tumour effect induced by paclitaxel in the tumour cell lines or tumour cells-implanted mice. These results suggest that neurotropin reverses the paclitaxel-induced neuropathy without affecting anti-tumour activity of paclitaxel, and therefore may be useful for the paclitaxel-induced neuropathy in clinical settings..
73. Nobuaki Egashira, Kenichi Mishima, Katsunori Iwasaki, Ryozo Oishi, Michihiro Fujiwara, New topics in vasopressin receptors and approach to novel drugs
Role of the vasopressin receptor in psychological and cognitive functions, Journal of Pharmacological Sciences, 10.1254/jphs.08R14FM, 109, 1, 44-49, 2009.01, Arginine vasopressin (AVP) is a neurohypophyseal peptide best known as an antidiuretic hormone. AVP receptors have been classified into three subtypes: V1a, V1b, and V2 receptors. V1a receptor (V1aR) and V1b receptor (V1bR) are widely distributed in the central nervous system, including the septum, cortex, hippocampus, and hypothalamus. Clinical studies have demonstrated an involvement of AVP in psychiatric disorders. In the present study, we examined the performance of V1aR or V1bR knockout (KO) mice compared to wild-type (WT) mice in behavioral tests. V1aR and V1bR KO mice exhibited deficits of social behavior and prepulse inhibition in comparison to WT mice. Moreover, V1aR KO mice exhibited reduced anxiety-like behavior and impairment of spatial learning. These results suggest that V1aR and V1bR play an important role in psychological and cognitive functions..
74. Kazuhide Hayakawa, Kenichi Mishima, Keiichi Irie, Mai Hazekawa, Shohei Mishima, Masayuki Fujioka, Kensuke Orito, Nobuaki Egashira, Shutaro Katsurabayashi, Kotaro Takasaki, Katsunori Iwasaki, Michihiro Fujiwara, Cannabidiol prevents a post-ischemic injury progressively induced by cerebral ischemia via a high-mobility group box1-inhibiting mechanism, Neuropharmacology, 10.1016/j.neuropharm.2008.06.040, 55, 8, 1280-1286, 2008.12, We examined the cerebroprotective mechanism of cannabidiol, the non-psychoactive component of marijuana, against infarction in a 4-h mouse middle cerebral artery (MCA) occlusion model. Cannabidiol was intraperitoneally administrated immediately before and 3 h after cerebral ischemia. Infarct size and myeloperoxidase (MPO) activity, a marker of neutrophil, monocyte/macropharge, were measured at 24 h after cerebral ischemia. Activated microglia and astrocytes were evaluated by immunostaining. Moreover, high-mobility group box1 (HMGB1) was also evaluated at 1 and 3 days after MCA occlusion. In addition, neurological score and motor coordination on the rota-rod test were assessed at 1 and 3 days after cerebral ischemia. Cannabidiol significantly prevented infarction and MPO activity at 20 h after reperfusion. These effects of cannabidiol were not inhibited by either SR141716 or AM630. Cannabidiol inhibited the MPO-positive cells expressing HMGB1 and also decreased the expression level of HMGB1 in plasma. In addition, cannabidiol decreased the number of Iba1- and GFAP-positive cells at 3 days after cerebral ischemia. Moreover, cannabidiol improved neurological score and motor coordination on the rota-rod test. Our results suggest that cannabidiol inhibits monocyte/macropharge expressing HMGB1 followed by preventing glial activation and neurological impairment induced by cerebral ischemia. Cannabidiol will open new therapeutic possibilities for post-ischemic injury via HMGB1-inhibiting mechanism..
75. Nobuaki Egashira, Ryoko Okuno, Moe Abe, Michihiko Matsushita, Kenichi Mishima, Katsunori Iwasaki, Ryozo Oishi, Ryoji Nishimura, Yoshiaki Matsumoto, Michihiro Fujiwara, Calcium-channel antagonists inhibit marble-burying behavior in mice, Journal of Pharmacological Sciences, 10.1254/jphs.08160SC, 108, 1, 140-143, 2008.10, In the present study, we examined the effects of calcium-channel antagonists on marble-burying behavior, which is an animal model of obsessive-compulsive disorder. Amlodipine (10 mg/kg, i.p.), cilnidipine (10 mg/kg, i.p.), nilvadipine (3 and 10 mg/kg, i.p.), and flunarizine (30 mg/kg, i.p.) significantly inhibited marble-burying behavior in mice. These results suggest that calcium channels may be involved in the marble-burying behavior..
76. Nobuaki Egashira, Ryoko Okuno, Michihiko Matsushita, Moe Abe, Kenichi Mishima, Katsunori Iwasaki, Ryoji Nishimura, Ryozo Oishi, Michihiro Fujiwara, Aripiprazole inhibits marble-burying behavior via 5-hydroxytryptamine (5-HT)1A receptor-independent mechanisms, European Journal of Pharmacology, 10.1016/j.ejphar.2008.06.100, 592, 1-3, 103-108, 2008.09, Aripiprazole is a first next-generation atypical antipsychotic drug with dopamine system stabilizing, serotonin (5-hydroxytryptamine, 5-HT) 5-HT1A receptor partial agonistic, and 5-HT2A receptor antagonistic properties. In the present study, we examined the effect of aripiprazole on marble-burying behavior, which has been considered an animal model of obsessive-compulsive disorder, and compared this with the effects of other atypical antipsychotics such as olanzapine and quetiapine. Aripiprazole (1 mg/kg, i.p.) inhibited marble-burying behavior without affecting the locomotor activity in mice. Conversely, olanzapine (3 mg/kg, i.p.) and quetiapine (100 mg/kg, p.o.) showed significant suppression of locomotor activity and impairment of motor coordination at the dose that inhibited marble-burying behavior. On the other hand, a selective 5-HT1A receptor antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexane (WAY100635, 3 mg/kg, i.p.) markedly antagonized the inhibition of marble-burying behavior by 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT, 3 mg/kg, i.p.), a selective 5-HT1A/7 receptor agonist. By contrast, WAY100635 at the same dose had no effect on the inhibition of marble-burying behavior by aripiprazole (1 mg/kg, i.p.). Quinpirole, a dopamine D2 receptor agonist, showed significant suppression of locomotor activity at the dose that inhibited marble-burying behavior. Conversely, L-741,626, a selective dopamine D2 receptor antagonist, at a dose of 10 mg/kg inhibited marble-burying behavior without affecting the locomotor activity. On the other hand, ketanserin, a 5-HT2A receptor antagonist, had no effect on the marble-burying behavior. These findings suggest that aripiprazole may be a useful drug for the treatment of obsessive-compulsive disorder, and that aripiprazole inhibits the marble-burying behavior via 5-HT1A receptor-independent mechanisms..
77. Nobuaki Egashira, Katsunori Iwasaki, Ayumi Ishibashi, Kazuhide Hayakawa, Ryoko Okuno, Moe Abe, Naoki Uchida, Kenichi Mishima, Kotaro Takasaki, Ryoji Nishimura, Ryozo Oishi, Michihiro Fujiwara, Repeated administration of Yokukansan inhibits DOI-induced head-twitch response and decreases expression of 5-hydroxytryptamine (5-HT)2A receptors in the prefrontal cortex, Progress in Neuro-Psychopharmacology and Biological Psychiatry, 10.1016/j.pnpbp.2008.05.010, 32, 6, 1516-1520, 2008.08, Behavioral and psychological symptoms of dementia (BPSD) are commonly seen in patients with Alzheimer's disease (AD) and other forms of senile dementia. BPSD have a serious impact on the quality of life of dementia patients, as well as their caregivers. However, an effective drug therapy for BPSD has not been established. Recently, the traditional Japanese medicine Yokukansan (YKS, Yi-gan san in Chinese) has been reported to improve BPSD in a randomized, single-blind, placebo-controlled study. Moreover, abnormalities of the serotonin (5-HT) system such as 5-HT2A receptors have been reported to be associated with BPSD of AD patients. In the present study, we investigated the effect of YKS on head-twitch response induced by 2,5-dimethoxy-4-iodoamphetamine (DOI, 5 mg/kg, i.p.) in mice, a behavioral response that is mediated, in part, by 5-HT2A receptors. Acute treatment with YKS (100 and 300 mg/kg, p.o.) had no effect on the DOI-induced head-twitch response, whilst 14 days repeated treatment with YKS (300 mg/kg, p.o.) significantly inhibited this response. Moreover, repeated treatment with YKS (300 mg/kg, p.o.) decreased expression of 5-HT2A receptors in the prefrontal cortex, which is part of the circuitry mediating the head-twitch response. These findings suggest that the inhibition of DOI-induced head-twitch response by YKS may be mediated, in part, by altered expression of 5-HT2A receptors in the prefrontal cortex, which suggests the involvement of the 5-HT system in psychopharmacological effects of YKS..
78. Hiroyuki Watanabe, Hiroaki Ikesue, Minoru Yoshida, Naoko Yamamoto, Setsuko Sakamoto, Tomoichiro Koga, Masanori Sueyasu, Nobuaki Egashira, Ichiro Inoshima, Yoichi Nakanishi, Ryozo Oishi, Protection against the extravasation of anticancer drugs by standardization of the management system, Hospital Pharmacy, 10.1310/hpj4307-571, 43, 7, 571-576, 2008.07, The extravasation of anticancer drugs is a serious complication. On the basis of data regarding extravasation prevention and treatment obtained primarily by pharmacists, the management system for extravasation of anticancer drugs was standardized at an outpatient chemotherapy center. A kit was prepared so that physicians could promptly and safely perform venipuncture; the kit included a classification list of anticancer drugs. Prior to administration of vesicant or irritant drugs, pharmacists and nurses educated the patients. When anticancer drugs were administered via peripheral vein without using an implanted venous access device, extravasation occurred in 10 out of 7,059 courses (0.14%) during the 2-year study period postintroduction of the present management system. This incidence is remarkably low as compared with those previously reported. The extravasated drugs were epirubicin (n = 3), paclitaxel (n = 3), vinorelbine (n = 1), 5-fluorouracil (n = 1), carboplatin (n = 1), and cyclophosphamide (n = 1). Cold packs were applied around the injection site except in the cases involving vinorelbine, in which warm packs were used. In all cases of extravasation of vesicant drugs, glucocorticoid was injected locally. There were no cases involving continuous pain or skin ulcers. The standardization of the management system for extravasation of anticancer drugs was very effective in decreasing the occurrence, as well as decreasing skin damage if it occurred..
79. Tomoko Aki, Nobuaki Egashira, Yui Yamauchi, Mika Hama, Takahisa Yano, Yoshinori Itoh, Takaaki Yamada, Ryozo Oishi, Protective effects of amino acids against Gabexate mesilate-induced cell injury in porcine-aorta endothelial cells, Journal of Pharmacological Sciences, 10.1254/jphs.08053FP, 107, 3, 238-245, 2008.07, Gabexate mesilate (GM), a serine protease inhibitor, often causes severe vascular injury. We previously reported that GM induced necrotic cell death via injury of the cell membrane in porcine aorta endothelial cells (PAECs). In the present study, we investigated the protective effects of amino acids against this GM-induced cell injury in PAECs. L-Cysteine (Cys), glycine (Gly), L-serine, L-glutamine (Gln), L-glutamate (Glu), L-proline, L-methionine, L-threonine, and L-isoleucine significantly inhibited the GM-induced decrease of cell viability. Gly showed the most potent effect among these amino acids. Gly, L-Cys, L-Glu, and L-Gln also inhibited the GM-induced increase in the number of necrotic cells stained by propidium iodide (PI). However, these amino acids had no effect on the GM-induced inhibition of trypsin activity. Strychnine, MK-801, or dichlorokynurenic acid did not affect the protective effect of Gly. Gly completely suppressed the GM-induced increase in PI uptake, which occurred immediately after exposure to GM. These findings suggest that Gly exerts protection against GM-induced cellular membrane injury, and several amino acids such as Gly may be useful for prophylaxis of the GM-induced severe vascular injury..
80. Nobuaki Egashira, Tomomi Matsuda, Emi Koushi, Fuminori Higashihara, Kenichi Mishima, Shozo Chidori, Nobuyoshi Hasebe, Katsunori Iwasaki, Ryoji Nishimura, Ryozo Oishi, Michihiro Fujiwara, Δ9-tetrahydrocannabinol prolongs the immobility time in the mouse forced swim test
Involvement of cannabinoid CB1 receptor and serotonergic system, European Journal of Pharmacology, 10.1016/j.ejphar.2008.03.046, 589, 1-3, 117-121, 2008.07, In the present study, we investigated the effect of Δ9-tetrahydrocannabinol (THC), the principal psychoactive component of marijuana, on immobility time during the forced swim test. THC (2 and 6 mg/kg, i.p.) significantly prolonged the immobility time. In addition, THC at the same doses did not significantly affect locomotor activity in the open-field test. The selective cannabinoid CB1 receptor antagonist rimonabant (3 mg/kg, i.p.) significantly reduced the enhancement of immobility by THC (6 mg/kg). Similarly, the selective serotonin (5-HT) reuptake inhibitor (SSRI) citalopram (10 mg/kg, i.p.) and 5-HT1A/7 receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT, 0.3 mg/kg, i.p.) significantly reduced this THC-induced effect. Moreover, the selective 5-HT1A receptor antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexane carboxamide dihydrochloride (WAY100635, 1 mg/kg, i.p.) and the postsynaptic 5-HT1A receptor antagonist MM-77 (0.1 mg/kg, i.p.) reversed this reduction effect of 8-OH-DPAT (0.3 mg/kg). In contrast, the selective 5-HT7 receptor antagonist (R)-3-[2-[2-(4-methylpiperidin-1-yl)ethyl]pyrrolidine-1-sulfonyl]phenol hydrochloride (SB269970) had no effect on this reduction effect of 8-OH-DPAT. WAY100635 (1 mg/kg) also reversed the reduction effect of citalopram (10 mg/kg). These findings suggest that the 5-HT1A receptors are involved in THC-induced enhancement of immobility..
81. K. Orito, M. Saito, K. Fukunaga, E. Matsuo, S. Takikawa, M. Muto, K. Mishima, Nobuaki Egashira, M. Fujiwara, Pharmacokinetics of zonisamide and drug interaction with phenobarbital in dogs, Journal of Veterinary Pharmacology and Therapeutics, 10.1111/j.1365-2885.2008.00955.x, 31, 3, 259-264, 2008.06, The purposes of the present study were to elucidate the pharmacokinetics of zonisamide, determine the presence of a drug interaction with phenobarbital, and evaluate how long any interaction lasted after discontinuation of phenobarbital in dogs. Five dogs received zonisamide (5 mg/kg, p.o. and i.v.) before and during repeated oral administration of phenobarbital (5 mg/kg, bid, for 30-35 days). Zonisamide (5 mg/kg, p.o.) was also administered 8, 10, and 12 weeks after discontinuation of phenobarbital. Blood was sampled until 24 h after each zonisamide administration and serum concentrations of zonisamide were determined. Repeated phenobarbital decreased the maximum serum concentration, area under the serum concentration vs. time curve, apparent elimination half-life, and bioavailability of zonisamide. Total clearance increased. Time to maximum serum concentration and volume distribution were not changed. The maximum serum concentration and area under the serum concentration vs. time curve of zonisamide continued to be low until 10 weeks after the discontinuation of phenobarbital. They were restored to the same serum concentration as before phenobarbital administration 12 weeks after the discontinuation of phenobarbital. These data suggested that repeated administration of a clinical dose of phenobarbital enhanced the clearance of zonisamide and the enhanced clearance lasted at least 10 weeks after the discontinuation of phenobarbital. Caution may be necessary when zonisamide is given with phenobarbital and when antiepileptic therapy is changed from phenobarbital to zonisamide..
82. Nobuaki Egashira, Ryoko Okuno, Satoko Harada, Michihiko Matsushita, Kenichi Mishima, Katsunori Iwasaki, Ryoji Nishimura, Ryozo Oishi, Michihiro Fujiwara, Effects of glutamate-related drugs on marble-burying behavior in mice
Implications for obsessive-compulsive disorder, European Journal of Pharmacology, 10.1016/j.ejphar.2008.01.035, 586, 1-3, 164-170, 2008.05, Clinical evidence demonstrates altered glutamatergic neurotransmission in patients suffering from obsessive-compulsive disorder (OCD). We examined the effects of glutamate-related drugs on marble-burying behavior, which is an animal model of OCD. The uncompetitive N-methyl-d-aspartate (NMDA) antagonists memantine (10 mg/kg, i.p.) and amantadine (30 mg/kg, i.p.) significantly inhibited marble-burying behavior without affecting locomotor activity in mice. Similarly, the uncompetitive NMDA receptor antagonist 5R,10S-(+)-5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclohepten-5,10-imine hydrogen maleate (MK-801, 0.3 mg/kg, i.p.) inhibited marble-burying behavior. However, MK-801 at the same dose markedly increased locomotor activity. By contrast, the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor antagonist 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide (NBQX) and the glutamate release inhibitor riluzole showed no effect on marble-burying behavior and significant suppression of locomotor activity. MK-801 (0.3 mg/kg, i.p.) and memantine (10 mg/kg, i.p.) significantly disrupted prepulse inhibition as an operational measure of sensorimotor gating. By contrast, amantadine (30 mg/kg, i.p.) did not affect prepulse inhibition. These findings suggest that amantadine could be a useful drug for the treatment of OCD..
83. Tomoko Aki, Nobuaki Egashira, Mika Hama, Yui Yamauchi, Takahisa Yano, Yoshinori Itoh, Ryozo Oishi, Characteristics of gabexate mesilate-induced cell injury in porcine aorta endothelial cells, Journal of Pharmacological Sciences, 10.1254/jphs.FP0072035, 106, 3, 415-422, 2008.04, Gabexate mesilate (GM), a serine protease inhibitor, often causes severe vascular injury, when injected in high concentration. In the present study, we investigated the mechanisms for the cytotoxicity of GM on porcine aorta endothelial cells (PAECs). GM (0.5 - 5.0 mM) decreased cell viability in a dose-dependent manner and caused cell injury, whilst nafamostat mesilate (NM), another serine protease inhibitor, or mesilate itself had no effect on cell viability. zVAD-fmk, a pancaspase inhibitor, or zDEVD-fmk, a caspase-3 inhibitor, did not affect the GM (1.5 mM)-induced decrease of cell viability. Apoptotic cells or DNA fragmentation were also not observed after GM treatment. Moreover, Ca2+ chelators, a nitric oxide (NO) synthase inhibitor, antioxidants, and radical scavengers had no effect on the GM-induced cell injury. On the other hand, cellular ATP content was decreased in the GM (2.0 mM)-treated cells. Surprisingly, GM (2.0 mM) immediately increased cellular uptake of propidium iodine. These findings suggest that GM induces necrotic cell death via injury of the cell membrane..
84. Takahisa Yano, Yoshinori Itoh, Masahiro Yamada, Nobuaki Egashira, Ryozo Oishi, Combined treatment with L-carnitine and a pan-caspase inhibitor effectively reverses amiodarone-induced injury in cultured human lung epithelial cells, Apoptosis, 10.1007/s10495-008-0186-9, 13, 4, 543-552, 2008.04, Amiodarone is an effective class III antiarrhythmic drug, however, the pulmonary toxicity is one of the most life-threatening complications of its use. The present study was designed to determine the mechanisms underlying pulmonary toxicity of amiodarone. In cultured human lung epithelial cells A549, amiodarone caused cell injury characterized by mitochondrial membrane depolarization, ATP depletion, enhanced propidium iodide (PI) uptake and increase in the number of Annexin-V positive cells, although the population of PI-stained cells appeared earlier and was not identical to that of Annexin-V stained cells, suggesting that the apoptosis and necrosis appeared in different cells. The apoptosis was accompanied with the activation of caspase-2, -3 and -8 but not caspase-9, and reversed by these caspase inhibitors. However, the caspase inhibitors had no influence on mitochondrial membrane potential or PI uptake after exposure of A549 cells to amiodarone. In contrast, mitochondrial cofactors such as L-carnitine and acetyl-l-carnitine attenuated mitochondrial membrane depolarization, abrogated cellular ATP depletion and reversed PI uptake without affecting Annexin-V positive cells. These finding suggest that different intracellular events operate to cause apoptosis and necrosis after exposure of pulmonary epithelial cells to amiodarone..
85. Kazuhide Hayakawa, Kenichi Mishima, Masanori Nozako, Mai Hazekawa, Shohei Mishima, Masayuki Fujioka, Kensuke Orito, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Delayed treatment with minocycline ameliorates neurologic impairment through activated microglia expressing a high-mobility group box1-inhibiting mechanism, Stroke, 10.1161/STROKEAHA.107.495820, 39, 3, 951-958, 2008.03, BACKGROUND AND PURPOSE - Minocycline, a semisynthetic tetracycline antibiotic, has been reported to ameliorate brain injury and inhibit microglial activation after focal cerebral ischemia. However, the cerebroprotective mechanism of minocycline remains unclear. In the present study, we investigated that mechanism of minocycline in a murine model of 4-hour middle cerebral artery (MCA) occlusion. METHODS - One day after 4-hour MCA occlusion, minocycline was administered intraperitoneally for 14 days. Neurologic scores were measured 1, 7, and 14 days after cerebral ischemia. Motor coordination was evaluated at 14 days by the rota-rod test at 10 rpm. Activated microglia and high-mobility group box1 (HMGB1), a cytokine-like mediator, were also evaluated by immunostaining and Western blotting. In addition, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling immunostaining was carried out 14 days after cerebral ischemia. RESULTS - Repeated treatment with minocycline (1, 5, and 10 mg/kg) for 14 days improved neurologic score, motor coordination on the rota-rod test, and survival in a dose-dependent manner. Minocycline decreased the expression of Iba1, a marker of activated microglia, as assessed by both immunostaining and Western blotting. Moreover, minocycline decreased the activation of microglia expressing HMGB1 within the brain and also decreased both brain and plasma HMGB1 levels. Additionally, minocycline significantly decreased the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling-positive cells and prevented ischemic brain atrophy 14 days after cerebral ischemia. CONCLUSIONS - Our results suggest that minocycline inhibits activated microglia expressing HMGB1 and decreases neurologic impairment induced by cerebral ischemia. Minocycline will have a palliative action and open new therapeutic possibilities for treatment of postischemic injury via an HMGB1-inhibiting mechanism..
86. Takuya Watanabe, Katsunori Iwasaki, Shin Ishikane, Tetsuya Naitou, Yoshitaka Yoshimitsu, Norito Yamagata, Mehmeto Bülent Ozdemir, Kotaro Takasaki, Nobuaki Egashira, Kenichi Mishima, Michihiro Fujiwara, Spatial memory impairment without apoptosis induced by the combination of beta-amyloid oligomers and cerebral ischemia is related to decreased acetylcholine release in rats, Journal of Pharmacological Sciences, 10.1254/jphs.FP0071648, 106, 1, 84-91, 2008.02, The purpose of the present study was to examine the effect of beta-amyloid (Aβ) oligomers, not the fibrils that make up Aβ plaques, on spatial memory and the cholinergic system in rats. Recently, several researchers have suggested that small assemblies of Aβ, Aβ oligomers, caused memory loss during the early stages of Alzheimer's disease without showing cell death. In the present study, the combination of Aβ oligomers and cerebral ischemia, but not cerebral ischemia alone, significantly impaired spatial memory without apoptosis in the CA1 region of the hippocampus. Donepezil, an acetylcholinesterase inhibitor, ameliorated this memory impairment. Therefore we examined acetylcholine (ACh) release from the dorsal hippocampus. A microdialysis study showed that spontaneous release of ACh was not significantly decreased by the combination of Aβ oligomers and cerebral ischemia; however, high K+-evoked ACh release was decreased. These results suggest that a combination of Aβ oligomers and cerebral ischemia induces memory impairment by cholinergic synapse dysfunction without apoptosis. This model may be useful for developing new drugs for the treatment of early-phase Alzheimer's disease..
87. Nobuaki Egashira, Noriko Ishigami, Kenichi Mishima, Katsunori Iwasaki, Ryozo Oishi, Michihiro Fujiwara, Δ9-Tetrahydrocannabinol-induced cognitive deficits are reversed by olanzapine but not haloperidol in rats, Progress in Neuro-Psychopharmacology and Biological Psychiatry, 10.1016/j.pnpbp.2007.10.001, 32, 2, 499-506, 2008.02, Cannabis is the most widely used illicit substance. Δ9-Tetrahydrocannabinol (THC), the major psychoactive component of cannabis, is known to induce cognitive impairment that closely resembles the impairment observed in schizophrenic patients. THC has also been known to impair spatial memory in rats tested in the eight-arm radial maze. We previously reported that microinjection of THC (20 μg/side) into the rat dorsal hippocampus impaired spatial memory and that i.p. injection of THC (6 mg/kg) decreased the extracellular levels of acetylcholine (ACh) in the dorsal hippocampus. In the present study, we compared the effects of olanzapine, an atypical antipsychotic, with those of haloperidol, a typical neuroleptic, on the impairments of spatial memory and decreased ACh levels induced by THC (6 mg/kg, i.p.) in rats. We found that olanzapine (0.1 mg/kg, i.p.) reversed the THC-induced memory deficits and decrease in extracellular ACh levels, whereas haloperidol (0.03-0.3 mg, i.p.) had no effect. These results suggest that olanzapine may improve the THC-induced impairment of spatial memory, partly by enhancing ACh release in the dorsal hippocampus. Therefore, olanzapine could attenuate the acute short-term and working memory deficits induced by cannabis..
88. Kazuhide Hayakawa, Kenichi Mishima, Mai Hazekawa, Kazunori Sano, Keiichi Irie, Kensuke Orito, Takashi Egawa, Yoshihisa Kitamura, Naoki Uchida, Ryoji Nishimura, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Cannabidiol potentiates pharmacological effects of Δ9-tetrahydrocannabinol via CB1 receptor-dependent mechanism, Brain Research, 10.1016/j.brainres.2007.09.090, 1188, 1, 157-164, 2008.01, Cannabidiol, a non-psychoactive component of cannabis, has been reported to have interactions with Δ9-tetrahydrocannabinol (Δ9-THC). However, such interactions have not sufficiently been clear and may have important implications for understanding the pharmacological effects of marijuana. In the present study, we investigated whether cannabidiol modulates the pharmacological effects of Δ9-THC on locomotor activity, catalepsy-like immobilisation, rectal temperature and spatial memory in the eight-arm radial maze task in mice. In addition, we measured expression level of cannabinoid CB1 receptor at striatum, cortex, hippocampus and hypothalamus. Δ9-THC (1, 3, 6 and 10 mg/kg) induced hypoactivity, catalepsy-like immobilisation and hypothermia in a dose-dependent manner. In addition, Δ9-THC (1, 3 and 6 mg/kg) dose-dependently impaired spatial memory in eight-arm radial maze. On the other hand, cannabidiol (1, 3, 10, 25 and 50 mg/kg) did not affect locomotor activity, catalepsy-like immobilisation, rectal temperature and spatial memory on its own. However, higher dose of cannabidiol (10 or 50 mg/kg) exacerbated pharmacological effects of lower dose of Δ9-THC, such as hypoactivity, hypothermia and impairment of spatial memory. Moreover, cannabidiol (50 mg/kg) with Δ9-THC (1 mg/kg) enhanced the expression level of CB1 receptor expression in hippocampus and hypothalamus. Cannabidiol potentiated pharmacological effects of Δ9-THC via CB1 receptor-dependent mechanism. These findings may contribute in setting the basis for interaction of cannabinoids and to find a cannabinoid mechanism in central nervous system..
89. Nobuaki Egashira, Kouji Kurauchi, Katsunori Iwasaki, Kenichi Mishima, Kensuke Orito, Ryozo Oishi, Michihiro Fujiwara, Schizandrin reverses memory impairment in rats, Phytotherapy Research, 10.1002/ptr.2258, 22, 1, 49-52, 2008.01, The present study investigated the effect of schizandrin, a component of the fruit of Schizandra chinesis Baill (Fructus Schizandrae), on memory impairment in rats. Scopolamine (0.5 mg/kg, i.p.), a non-selective muscarinic receptor antagonist, markedly impaired spatial memory in an eight-arm radial maze. A higher dose of scopolamine (3 mg/kg, i.p.) also impaired the passive avoidance response. Schizandrin (1 and 10 mg/kg, p.o.) significantly reversed the scopolamine-induced impairment of spatial memory. Similarly, schizandrin (1 mg/kg, p.o.) significantly reversed the scopolamine-induced impairment of the passive avoidance response. Moreover, in mice, schizandrin (1 and 10 mg/kg, p.o.) enhanced tremors induced by oxotremorine, a muscarinic M1 receptor agonist. Taken together these findings suggest that schizandrin reverses scopolamine-induced memory impairment, in part, by enhancing cholinergic function, and that schizandrin might be useful for treating memory deficits..
90. Nobuaki Egashira, Noriko Ishigami, Fengling Pu, Kenichi Mishima, Katsunori Iwasaki, Kensuke Orito, Ryozo Oishi, Michihiro Fujiwara, Theanine prevents memory impairment induced by repeated cerebral ischemia in rats, Phytotherapy Research, 10.1002/ptr.2261, 22, 1, 65-68, 2008.01, The present study investigated the neuroprotective effect of γ-glutamylethylamide (theanine), a component Japanese green tea (Camellia sinensis), on memory impairment induced by twice-repeated cerebral ischemia in rats. Theanine was injected i.p. immediately after the first occlusion. Theanine (0.3 and 1 mg/kg) significantly prevented the impairment of spatial memory in rats subjected to repeated cerebral ischemia, 7 days after the second reperfusion. Moreover, theanine (1 mg/kg) significantly inhibited the decrease in the number of surviving cells in the hippocampal CA1 field in the same rats. These results suggest that theanine prevents memory impairment induced by repeated cerebral ischemia, in part by protecting against neuronal cell death, and that it might be useful for preventing cerebrovascular disease..
91. K. Sano, K. Mishima, E. Koushi, K. Orito, Nobuaki Egashira, K. Irie, K. Takasaki, S. Katsurabayashi, K. Iwasaki, N. Uchida, T. Egawa, Y. Kitamura, R. Nishimura, M. Fujiwara, Δ9-Tetrahydrocannabinol-induced catalepsy-like immobilization is mediated by decreased 5-HT neurotransmission in the nucleus accumbens due to the action of glutamate-containing neurons, Neuroscience, 10.1016/j.neuroscience.2007.10.026, 151, 2, 320-328, 2008.01, Δ9-Tetrahydrocannabinol (THC) has been reported to induce catalepsy-like immobilization, but the mechanism underlying this effect remains unclear. In the present study, in order to fully understand the neural circuits involved, we determined the brain sites involved in the immobilization effect in rats. THC dose-dependently induced catalepsy-like immobilization. THC-induced catalepsy-like immobilization is mechanistically different from that induced by haloperidol (HPD), because unlike HPD-induced catalepsy, animals with THC-induced catalepsy became normal again following sound and air-puff stimuli. THC-induced catalepsy was reversed by SR141716, a selective cannabinoid CB1 receptor antagonist. Moreover, THC-induced catalepsy was abolished by lesions in the nucleus accumbens (NAc) and central amygdala (ACE) regions. On the other hand, HPD-induced catalepsy was suppressed by lesions in the caudate putamen (CP), substantia nigra (SN), globus pallidus (GP), ACE and lateral hypothalamus (LH) regions. Bilateral microinjection of THC into the NAc region induced catalepsy-like immobilization. This THC-induced catalepsy was inhibited by serotonergic drugs such as 5-hydroxy-L-tryptophan (5-HTP), a 5-HT precursor, and 5-methoxy-N,N-dimethyltryptamine (5-MeODMT), a 5-HT receptor agonist, as well as by anti-glutamatergic drugs such as MK-801 and amantadine, an N-methyl-d-aspartate (NMDA) receptor antagonist. THC significantly decreased 5-HT and glutamate release in the NAc, as shown by in vivo microdialysis. SR141716 reversed and MK-801 inhibited this decrease in 5-HT and glutamate release. These findings suggest that the THC-induced catalepsy is mechanistically different from HPD-induced catalepsy and that the catalepsy-like immobilization induced by THC is mediated by decreased 5-HT neurotransmission in the nucleus accumbens due to the action of glutamate-containing neurons..
92. Nobuaki Egashira, Emi Koushi, Kenichi Mishima, Katsunori Iwasaki, Ryozo Oishi, Michihiro Fujiwara, 2,5-Dimethoxy-4-iodoamphetamine (DOI) inhibits Δ9- tetrahydrocannabinol-induced catalepsy-like immobilization in mice, Journal of Pharmacological Sciences, 10.1254/jphs.FP0071247, 105, 4, 361-366, 2007.12, The effect of the serotonin 5-HT2A/2C-receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) on Δ9- tetrahydrocannabinol (THC)-induced catalepsy-like immobilization was studied in mice. DOI (0.3 and 1 mg/kg, i.p.) significantly inhibited the catalepsy-like immobilization induced by THC (10 mg/kg, i.p.). In contrast, the selective 5-HT2C-receptor agonist 8,9-dichloro-2,3,4,4a-tetrahydro-1H- pyrazino[1,2-a]quinoxalin-5(6H)-one (WAY 161503) had no effect on this catalepsy-like immobilization. Moreover, the 5-HT2A-receptor antagonist ketanserin (0.3 mg/kg, i.p.) reversed the inhibition of THC-induced catalepsy-like immobilization caused by DOI (1 mg/kg), whereas the selective 5-HT2C-receptor antagonist 6-chloro-2,3-dihydro-5-methyl-N-[6-(2- methyl-3-pyridinyl)oxyl]-3-pyridinyl]-1H-indole-1-carboxyamide (SB 242084) did not affect this inhibitory effect of DOI. On the other hand, ketanserin (0.3 and 1 mg/kg, i.p.) enhanced the catalepsy-like immobilization induced by THC (6 mg/kg, i.p.). Thus, on the basis of these results, it appears that 5-HT 2A-receptor mechanisms might be responsible for the inhibitory effect of DOI on THC-induced catalepsy-like immobilization..
93. Nobuaki Egashira, Kazuhide Hayakawa, Megumi Osajima, Kenichi Mishima, Katsunori Iwasaki, Ryozo Oishi, Michihiro Fujiwara, Involvement of GABAA receptors in the neuroprotective effect of theanine on focal cerebral ischemia in mice, Journal of Pharmacological Sciences, 10.1254/jphs.SCZ070901, 105, 2, 211-214, 2007.11, We investigated the involvement of γ-aminobutyric acidA (GABA A) receptors in the neuroprotective effect of γ- glutamylethylamide (theanine), a component of Japanese green tea, following a 4-h middle cerebral artery (MCA) occlusion in mice. Theanine (1 mg/kg) reduced the size of the cerebral infarct and alterations of NeuN, GFAP, and Iba 1 expression levels at 24 h after MCA occlusion. This neuroprotective effect of theanine was prevented by bicuculline (GABAA-receptor antagonist, 10 mg/kg) but not 3-mercaptopropionic acid (glutamate decarboxylase inhibitor). These results suggest that the neuroprotective effect of theanine is mediated, at least in part, by GABAA receptors..
94. Takahisa Yano, Yoshinori Itoh, Misaki Matsuo, takehiro kawashiri, Nobuaki Egashira, Ryozo Oishi, Involvement of both tumor necrosis factor-α-induced necrosis and p53-mediated caspase-dependent apoptosis in nephrotoxicity of cisplatin, Apoptosis, 10.1007/s10495-007-0110-8, 12, 10, 1901-1909, 2007.10, We previously reported that necrosis occurs predominantly in porcine renal tubular LLC-PK1 cells, when the cells were exposed transiently to a high concentration of cisplatin. Moreover, we demonstrated that generation of reactive oxygen species and subsequent production of tumor necrosis factor-α (TNF-α) through phosphorylation of p38 MAPK are implicated in the pathogenesis of cisplatin-induced renal cell injury. However, some TUNEL-positive cells appeared in renal proximal tubules of rats after systemic injection of cisplatin, suggesting an involvement of apoptosis. In the present study, we found in LLC-PK1 cells that both apoptosis and necrosis were elicited when the cells were exposed to 200 μM cisplatin for 1 h followed by incubation for 24 h in the presence of 20 μM cisplatin. The cisplatin-induced necrosis was largely attenuated by the antioxidant N-acetylcysteine, while apoptosis was prevented by the specific inhibitors for caspases-2, -8, and -3 and a p53 inhibitor pifithrin-α but not by the p38 MAPK inhibitor SB203580. On the other hand, SB203580 attenuated the cisplatin-induced increase in TNF-α production. These findings suggest that p53-mediated activations of caspases-2, -8 and -3 play a key role in cisplatin-induced renal cell apoptosis, while oxidative stress-induced TNF-α synthesis via p38 MAPK phosphorylation contributed to the necrosis..
95. Kazuhide Hayakawa, Kenichi Mishima, Masanori Nozako, Mai Hazekawa, Keiichi Irie, Masayuki Fujioka, Kensuke Orito, Kohji Abe, Nobuyoshi Hasebe, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Delayed treatment with cannabidiol has a cerebroprotective action via a cannabinoid receptor-independent myeloperoxidase-inhibiting mechanism, Journal of Neurochemistry, 10.1111/j.1471-4159.2007.04565.x, 102, 5, 1488-1496, 2007.09, We examined the neuroprotective mechanism of cannabidiol, non-psychoactive component of marijuana, on the infarction in a 4 h mouse middle cerebral artery (MCA) occlusion model in comparison with Δ9- tetrahydrocannabinol (Δ9-THC). Release of glutamate in the cortex was measured at 2 h after MCA occlusion. Myeloperoxidase (MPO) and cerebral blood flow were measured at 1 h after reperfusion. In addition, infarct size and MPO were determined at 24 and 72 h after MCA occlusion. The neuroprotective effect of cannabidiol was not inhibited by either SR141716 or AM630. Both pre- and post-ischemic treatment with cannabidiol resulted in potent and long-lasting neuroprotection, whereas only pre-ischemic treatment with Δ9-THC reduced the infarction. Unlike Δ9-THC, cannabidiol did not affect the excess release of glutamate in the cortex after occlusion. Cannabidiol suppressed the decrease in cerebral blood flow by the failure of cerebral microcirculation after reperfusion and inhibited MPO activity in neutrophils. Furthermore, the number of MPO-immunopositive cells was reduced in the ipsilateral hemisphere in cannabidiol-treated group. Cannbidiol provides potent and long-lasting neuroprotection through an anti-inflammatory CB1 receptor-independent mechanism, suggesting that cannabidiol will have a palliative action and open new therapeutic possibilities for treating cerebrovascular disorders..
96. Fengling Pu, Kenichi Mishima, Keiichi Irie, Kyouko Motohashi, Yurika Tanaka, Kensuke Orito, Takashi Egawa, Yoshihisa Kitamura, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Neuroprotective effects of quercetin and rutin on spatial memory impairment in an 8-arm radial maze task and neuronal death induced by repeated cerebral ischemia in rats, Journal of Pharmacological Sciences, 10.1254/jphs.FP0070247, 104, 4, 329-334, 2007.09, In order to determine the differential effects of flavonoids on cerebral ischemia, we investigated the effects of (-)-epigallocatechin gallate (EGCG), catechin, rutin, and quercetin on spatial memory impairment and neuronal death induced by repeated cerebral ischemia in rats. Both rutin and quercetin (50 mg/kg x 2) improved spatial memory impairment in the 8-arm radial maze task and neuronal death in the hippocampal CA1 area; however, catechin (200 mg/kg x 2) and EGCG (50 mg/kg x 1) did not. Administration of EGCG (50 mg/kg x 2) resulted in a high mortality rate. These results suggest that in this repeated cerebral ischemia model, the 4-oxo group and the 2,3-double bond in the C ring of rutin and quercetin are related to their neuroprotective action..
97. Nobuaki Egashira, Satoko Harada, Ryoko Okuno, Michihiko Matsushita, Ryoji Nishimura, Kenichi Mishima, Katsunori Iwasaki, Kensuke Orito, Michihiro Fujiwara, Involvement of the sigma1 receptor in inhibiting activity of fluvoxamine on marble-burying behavior
Comparison with paroxetine, European Journal of Pharmacology, 10.1016/j.ejphar.2007.02.019, 563, 1-3, 149-154, 2007.06, In the present study, we examined the involvement of the sigma1 receptor in the inhibitory effect of the selective serotonin reuptake inhibitor (SSRI) fluvoxamine, compared with that of paroxetine, on marble-burying behavior, which is an animal model of obsessive-compulsive disorder. Sigma1 receptor agonists (+)-SKF 10047 and PRE-084 significantly inhibited marble-burying behavior. Sigma receptor antagonist BD 1047 and selective sigma1 receptor antagonist BD 1063 significantly attenuated the inhibition of marble-burying behavior by fluvoxamine. In contrast, selective sigma2 receptor antagonist SM-21 failed to affect the inhibition of marble-burying behavior by fluvoxamine. On the other hand, BD 1047 and BD 1063 had no effect on the inhibition of marble-burying behavior by paroxetine. These observations show that activation of the sigma1 receptor is a necessary component in the inhibitory effect of fluvoxamine on marble-burying behavior, and that the mechanism of its action is clearly different from that of paroxetine..
98. Kensuke Orito, Nanae Gotanda, Masaru Murakami, Tomoaki Ikeda, Nobuaki Egashira, Kenichi Mishima, Michihiro Fujiwara, Prenatal exposure to 3,3′,4,4′,5-pentachlorobiphenyl (PCB126) promotes anxiogenic behavior in rats, Tohoku Journal of Experimental Medicine, 10.1620/tjem.212.151, 212, 2, 151-157, 2007.06, Polychlorinated biphenyls (PCBs) are environmental contaminants that have adverse effects on the endocrine and nervous systems. As they are still detected in breast milk and adipose tissue in humans, the accumulated PCBs may transfer from mothers to children and damage central nervous system. It is revealed from epidemiological studies that cognitive and motor functions were damaged in children born to mothers who ingested PCBs-contaminated foods. However, it remains unclear whether prenatal exposure to PCBs affects emotionality. In the present study, we therefore examined the effect of prenatal exposure to 3,3',4, 4',5-pentachlorobiphenyl (PCB126) on emotionality in rats by focusing on anxiogenic behavior and response of the hypothalamus-pituitary-adrenal axis to stress. Pregnant rats were treated orally with PCB126 at a dose of 30,μg/kg or corn oil, its vehicle, on gestational day 15, and their male offspring were subjected to the following experiments at 4-5 weeks old. In an open field test, rats with prenatal exposure to PCB126 showed anxiogenic behavioral responses, including decrease in time spent in the center of an open field and the number of rearings and extension of grooming duration. Interactive behavior, which is an index of anxiety level, was shortened in the social interaction test. The increase in the serum corticosterone level induced by forced swim stress was facilitated by prenatal exposure to PCB126. This evidence suggests that PCB126 may exert anxiogenicity on the offspring of exposed dams, and dysfunction of the hypothalamus-pituitary-adrenal axis may at least in part contribute to this abnormality..
99. Katsunori Iwasaki, Nobuaki Egashira, Yuki Takagaki, Yoshitaka Yoshimitsu, Izzettin Hatip-Al-Khatib, Kenichi Mishima, Michihiro Fujiwara, Nilvadipine prevents the impairment of spatial memory induced by cerebral ischemia combined with β-amyloid in rats, Biological and Pharmaceutical Bulletin, 10.1248/bpb.30.698, 30, 4, 698-701, 2007.04, In the present study, we examined the effects of nilvadipine and amlodipine, both dihydropyridine-derivative calcium antagonists, on the impairment of spatial memory induced by a combination of ischemia and β-amyloid (Aβ). Nilvadipine (3.2 mg/kg, i.p.) significantly prevented the impairment of spatial memory and neuronal apoptosis in this model. By contrast, amlodipine had no effect on this impairment of spatial memory. These findings suggest that nilvadipine may prevent impairment of spatial memory by inhibiting neuronal apoptosis; this drug might therefore be useful for the prevention of the progression to dementia in Alzheimer's disease (AD)..
100. Izzettin Hatip-Al-Khatib, Funda Bölukbaşi Hatip, Yoshitaka Yoshimitsu, Katsunori Iwasaki, Nobuaki Egashira, An Xin Liu, Kenichi Mishima, Michihiro Fujiwara, Effect of Toki-Shakuyaku-San on acetylcholine level and blood flow in dorsal hippocampus of intact and twice-repeated ischemic rats, Phytotherapy Research, 10.1002/ptr.2050, 21, 3, 291-294, 2007.03, The effects of Toki-shakuyaku-san (TSS) ingredients on acetylcholine (ACh) release in the dorsal hippocampus (DH) were investigated in intact and twice-repeated ischemic rats using in vivo microdialysis-HPLC. Moreover, the effect of TSS on blood flow was investigated in intact rats using laser Doppler flowmetry. TSS at 300 mg/kg p.o. increased ACh and blood flow after 40 min in intact rats. TSS also increased ACh in ischemic rats but to a lesser extent than in intact rats. These results could suggest that TSS-increased ACh and blood flow in DH may contribute in the cognition improving property of TSS..
101. Kazuhide Hayakawa, Kenichi Mishima, Masanori Nozako, Mai Hazekawa, Yo Aoyama, Ayumi Ogata, Kazuhiko Harada, Masayuki Fujioka, Kohji Abe, Nobuaki Egashira, Katunori Iwasaki, Michihiro Fujiwara, High-cholesterol feeding aggravates cerebral infarction via decreasing the CB1 receptor, Neuroscience Letters, 10.1016/j.neulet.2006.12.022, 414, 2, 183-187, 2007.03, We examined how feeding conditions affect the CB1 receptor and cerebral infarction caused by cerebral ischemia. Mice were divided into the following three groups: normal diet (ND), caloric restriction (CR) and high-cholesterol-enriched diet (HCD), and were kept for 6 weeks. After 6 weeks, we measured both serum and brain cholesterol and the expression level of cannabinoid CB1 receptor within the brain in intact mice. In addition, middle cerebral artery (MCA) was occluded for 2 h following reperfusion. Serum cholesterol significantly increased in the HCD group in comparison with both the ND and CR groups. However, brain cholesterol decreased in the HCD group. Then, the expression level of CB1 receptor significantly decreased in the HCD group, while that of the CR group clearly increased in comparison with the ND group in intact mice. In MCA-occluded mice, The HCD group produced the most severe cerebral infarction, while cerebral infarction was significantly decreased in the CR group. These results suggest that CR prevents infarction by increasing CB1 receptor expression, while high-cholesterol feeding aggravates cerebral infarction both by hypercholesterolemia in serum and by decreasing CB1 receptor expression modulated by hypocholesterolemia within the brain..
102. Nobuaki Egashira, Akito Tanoue, Tomomi Matsuda, Emi Koushi, Satoko Harada, Yukio Takano, Gozoh Tsujimoto, Kenichi Mishima, Katsunori Iwasaki, Michihiro Fujiwara, Impaired social interaction and reduced anxiety-related behavior in vasopressin V1a receptor knockout mice, Behavioural Brain Research, 10.1016/j.bbr.2006.12.009, 178, 1, 123-127, 2007.03, The arginine vasopressin (AVP) system plays an important role in social behavior. Autism, with its hallmark disturbances in social behavior, has been associated with the V1a receptor (V1aR) gene. Furthermore, impairments of social function are often observed in symptoms of schizophrenia. Subchronic phencyclidine (PCP) produces behaviors relating to certain aspects of schizophrenic symptoms such as impairing social interaction in animals and it reduces the density of V1aR binding sites in several brain regions. Here, we report that V1aR knockout (KO) mice exhibited impairment of social behavior in a social interaction test, and showed reduced anxiety-related behavior in elevated plus-maze and marble-burying behavior tests. Given the current findings, the V1aR may be involved in the regulation of social interaction, and V1aR KO mice could be used as an animal model of psychiatric disorders associated with social behavior deficits, such as autism and schizophrenia..
103. Kazuhide Hayakawa, Kenichi Mishima, Masanori Nozako, Ayumi Ogata, Mai Hazekawa, An Xin Liu, Masayuki Fujioka, Kohji Abe, Nobuyoshi Hasebe, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Repeated treatment with cannabidiol but not Δ9-tetrahydrocannabinol has a neuroprotective effect without the development of tolerance, Neuropharmacology, 10.1016/j.neuropharm.2006.11.005, 52, 4, 1079-1087, 2007.03, Both Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol are known to have a neuroprotective effect against cerebral ischemia. We examined whether repeated treatment with both drugs led to tolerance of their neuroprotective effects in mice subjected to 4 h-middle cerebral artery (MCA) occlusion. The neuroprotective effect of Δ9-THC but not cannabidiol was inhibited by SR141716, cannabinoid CB1 receptor antagonist. Fourteen-day repeated treatment with Δ9-THC, but not cannabidiol, led to tolerance of the neuroprotective and hypothermic effects. In addition, repeated treatment with Δ9-THC reversed the increase in cerebral blood flow (CBF), while cannabidiol did not reverse that effect. Repeated treatment with Δ9-THC caused CB1 receptor desensitization and down-regulation in MCA occluded mice. On the contrary, cannabidiol did not influence these effects. Moreover, the neuroprotective effect and an increase in CBF induced by repeated treatment with cannabidiol were in part inhibited by WAY100135, serotonin 5-HT1A receptor antagonist. Cannabidiol exhibited stronger antioxidative power than Δ9-THC in an in vitro study using the 1,1-diphenyl-2-picryhydrazyl (DPPH) radical. Thus, cannabidiol is a potent antioxidant agent without developing tolerance to its neuroprotective effect, acting through a CB1 receptor-independent mechanism. It is to be hoped that cannabidiol will have a palliative action and open new therapeutic possibilities for treating cerebrovascular disorders..
104. Kazuhide Hayakawa, Kenichi Mishima, Masanori Nozako, Mai Hazekawa, Ayumi Ogata, Masayuki Fujioka, Kazuhiko Harada, Shohei Mishima, Kensuke Orito, Nobuaki Egashira, Katunori Iwasaki, Michihiro Fujiwara, Δ9-tetrahydrocannabinol (Δ9-THC) prevents cerebral infarction via hypothalamic-independent hypothermia, Life Sciences, 10.1016/j.lfs.2007.01.014, 80, 16, 1466-1471, 2007.03, Δ9-tetrahydrocannabinol (Δ9-THC), a primary psychoactive constituent of cannabis, has been reported to act as a neuroprotectant via the cannabinoid CB1 receptor. In this study, Δ9-THC significantly decreased the infarct volume in a 4 h mouse middle cerebral artery occlusion mouse model. The neuroprotective effect of Δ9-THC was completely abolished by SR141716, cannabinoid CB1 receptor antagonist, and by warming the animals to 31 °C. Δ9-THC significantly decreased the rectal temperature, and the hypothermic effect was also inhibited by SR141716 and by warming to 31 °C. At 24 h after cerebral ischemia, Δ9-THC significantly increased the expression level of CB1 receptor in both the striatum and cortex, but not in the hypothalamus. Warming to 31 °C during 4 h cerebral ischemia did not increase the expression of CB1 receptor at the striatum and cortex in MCA-occluded mice. These results show that the neuroprotective effect of Δ9-THC is mediated by a temperature-dependent mechanism via the CB1 receptor. In addition, warming to 31 °C might attenuate both the neuroprotective and hypothermic effects of Δ9-THC through inhibiting the increase in CB1 receptor in both the striatum and cortex but not in the hypothalamus, which may suggest a new thermoregulation mechanism of Δ9-THC..
105. Izzettin Hatip-Al-Khatib, Katsunori Iwasaki, Nobuaki Egashira, Daisuke Ishibashi, Kenichi Mishima, Michihiro Fujiwara, Comparison of single- and repeated-ischemia-induced changes in expression of flip and flop splice variants of AMPA receptor subtypes GluR1 and GluR2 in the rats hippocampus CA1 subregion, Journal of Pharmacological Sciences, 10.1254/jphs.FP0061229, 103, 1, 83-91, 2007.02, In addition to their role in physiological activities, ionotropic glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors (AMPARs) play an important role in neuronal death, especially that following ischemic insults. In this study, we examined the effect of single (SI) and twice repeated (RI)-4-vessel occlusion-ischemia on rat performance in the 8-armed radial maze test. Moreover, the effects of SI and RI on the AMPARs subunits glutamate receptor (GluR) 1 and GluR2 flip and flop variants composition in the CA1 subregion of the hippocampus were investigated using RT-PCR, normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and expressed as their ratios to the latter. The results showed that SI and RI impaired the maze performance by decreasing correct choices and increasing the error choices, but RI increased error choices to a greater extent than the SI. The SI reduced only GluR1 flip/GAPDH on day 1. The SI did not alter ratios of GluR2 variants to those of GluR1. On the other hand, the RI decreased GluR2 flip and flop variants after 1 and 3 days, respectively, whereas after 7 days, it increased the flip variant of both GluR1 and GluR2. Moreover, the RI reduced ratios of GluR2 variants to those of GluR1. These results reveal the differential effects of the SI and RI on memory and expression of the AMPARs subunits GluR1 and GluR2 and their flip and flop variants in the CA1..
106. Nobuaki Egashira, Naomi Manome, Kouji Kurauchi, Yoshiaki Matsumoto, Katsunori Iwasaki, Kenichi Mishima, Yukihiro Shoyama, Michihiro Fujiwara, Kamikihi-to, a Kampo medicine, ameliorates impairment of spatial memory in rats, Phytotherapy Research, 10.1002/ptr.2034, 21, 2, 126-129, 2007.02, The present study investigated the effects of Kamikihi-to (KKT), a Kampo medicine, on impairment of spatial memory in rats using an eight-arm radial maze task. Scopolamine (0.5 mg/kg, i.p.), a non-selective muscarinic receptor antagonist, and Δ9-tetrahydrocannabinol (THC; 6 mg/kg, i.p.), a principal psychoactive component of marihuana, each markedly impaired the spatial memory. KKT (1 and 3 mg/kg, p.o.) significantly improved the scopolamine-induced impairment of spatial memory. KKT (30 mg/kg, p.o.) also improved significantly the THC-induced impairment of spatial memory. Moreover, KKT (3 and 30 mg/kg, p.o.) enhanced tremors induced by oxotremorine, a muscarinic M1 receptor agonist. Taken together these findings suggest that KKT is a useful drug for treating memory deficits..
107. Michihiro Fujiwara, Nobuaki Egashira, Kenichi Mishima, Katsunori Iwasaki, Nobuaki Egashira, Tokishakuyakusan
Pharmacological evidence for neuroactive and neuroprotective actions, Journal of Traditional Medicines, 10.11339/jtm.24.149, 24, 5, 149-155, 2007.01, The present article introduces our study related to the neuroactive and neuroprotective effects of Tokishakuyakusan (TSS) on animal model of Alzheimers disease (AD) or cerebrovascular dementia. Single administration of TSS ameliorates the impairment of spatial memory induced by scopolamine in radial maze test and enhances tremors induced by oxotremorine, a muscarinic M1 receptor agonist. We found that Ang-S-1, which is a partial inverse agonist of benzodiazepine, was an active compound of TSS in improving effect on impairment of spatial memory in radial maze test. We also found that single administration of TSS increased both acetylcholine (ACh) release and blood flow in the dorsal hippocampus, and TSS protected against neurotoxicity induced by amyloid β protein (Aβ). In animal model of AD or cerebrovascular dementia, we found that TSS prevented the impairment of spatial memory, neuronal death and TUNEL positive cells induced by repeated ischemia, and TSS prevented the impairment of spatial memory and decrease of ACh release induced by ovariectomized combined with Aβ. The present findings show that TSS prevents the memory deficits through not only enhancing ACh release but also protecting neuronal damage. Thus, TSS exhibits the neuroactive and neuroprotective effects in animal model of AD or cerebrovascular dementia, and therefore may be useful in the treatment of these dementia..
108. Kenta Umeda, Katsuya Suemaru, Nobuko Todo, Nobuaki Egashira, Kenichi Mishima, Katsunori Iwasaki, Michihiro Fujiwara, Hiroaki Araki, Effects of mood stabilizers on the disruption of prepulse inhibition induced by apomorphine or dizocilpine in mice, European Journal of Pharmacology, 10.1016/j.ejphar.2006.09.050, 553, 1-3, 157-162, 2006.12, The prepulse inhibition of the startle response provides an operational measure of sensorimotor gating in which a weak stimulus presented prior to a startling stimulus reduces the startle response. Prepulse inhibition deficits were observed in patients with several neuropsychiatric disorders, including schizophrenia and acute manic bipolar patients. Valproic acid, carbamazepine and lithium carbonate are frequently used as mood stabilizers in patients with bipolar affective disorder and schizophrenia. However, little is known about the mechanisms of action of mood stabilizers on prepulse inhibition deficits. In this study, we investigated the effects of mood stabilizers on the disruption of prepulse inhibition of the acoustic startle response induced by either apomorphine or dizocilpine in mice. Valproate (30-300 mg/kg, i.p.), carbamazepine (3-30 mg/kg, i.p.) and lithium carbonate (10-100 mg/kg, p.o.) had any effect on prepulse inhibition by itself. Valproate, carbamazepine and lithium carbonate reversed the disruption of prepulse inhibition induced by apomorphine (1 mg/kg, s.c.). Although valproate and carbamazepine had no effect on the disruption of prepulse inhibition induced by dizocilpine (0.3 mg/kg, s.c.), lithium carbonate exacerbated the dizocilpine-induced disruption. These results suggest that valproate, carbamazepine and lithium carbonate reverse the disruption of prepulse inhibition through the dopaminergic system..
109. Fujio Umehara, Kenichi Mishima, Nobuaki Egashira, Ayumi Ogata, Katsunori Iwasaki, Michihiro Fujiwara, Elevated anxiety-like and depressive behavior in Desert hedgehog knockout male mice, Behavioural Brain Research, 10.1016/j.bbr.2006.07.022, 174, 1, 167-173, 2006.11, To investigate the functional role of Desert hedgehog (Dhh) gene in the nervous system, we examined motor, sensory, learning and memory functions as well as mood in Dhh knockout (KO) mice. Dhh KO male mice exhibited prolonged immobility time compared with wild-type male mice in the forced swimming test, and showed enhanced inhibition in the Vogel's conflict model. These findings suggest that Dhh KO male mice exhibited enhanced anxiety and depressive behavior compared with wild-type male mice. In contrast, Dhh KO female mice did not show any significant difference compared to wild-type female mice. These behavioral abnormalities of Dhh KO male mice may be due to lower testosterone levels with abnormal development of the testes caused by Dhh-null mutation..
110. Nobuaki Egashira, Tomomi Matsuda, Emi Koushi, Kenichi Mishima, Katsunori Iwasaki, Yukihiro Shoyama, Michihiro Fujiwara, Involvement of 5-hydroxytryptamine1A receptors in Δ9-tetrahydrocannabinol-induced catalepsy-like immobilization in mice, European Journal of Pharmacology, 10.1016/j.ejphar.2006.08.051, 550, 1-3, 117-122, 2006.11, The present study investigated the involvement of 5-hydroxytryptamine1A (5-HT1A) receptors in Δ9-tetrahydrocannabinol (THC)-induced catalepsy-like immobilization in mice. THC (10 mg/kg, i.p.) induced catalepsy-like immobilization but had no effect on motor coordination in the rota-rod test. The selective cannabinoid CB1 receptor antagonist rimonabant (3 mg/kg, i.p.) completely antagonized THC-induced catalepsy-like immobilization. The 5-HT1A/5-HT7 receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT; 0.3 and 1 mg/kg, i.p.) and 5-HT1A receptor partial agonist buspirone (0.06 and 0.1 mg/kg, i.p.) inhibited this THC-induced catalepsy-like immobilization. Moreover, the selective 5-HT1A receptor antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohezane carboxamide dihydrochloride (WAY100635; 0.3 or 1 mg/kg, i.p.) reversed the inhibition of THC-induced catalepsy-like immobilization by 8-OH-DPAT (1 mg/kg) or buspirone (0.06 mg/kg). In contrast, the selective 5-HT7 receptor antagonist (R)-3-[2-[2-(4-methylpiperidin-1-yl)ethyl]pyrrolidine-1-sulfonyl]phenol hydrochloride (SB269970) had no effect on this inhibitory effect of 8-OH-DPAT. On the other hand, WAY100635 (0.3 and 1 mg/kg, i.p.) enhanced the catalepsy-like immobilization induced by THC (6 mg/kg, i.p.). These findings suggest that the 5-HT1A receptors are involved in THC-induced catalepsy-like immobilization..
111. Hiroshi Nagai, Nobuaki Egashira, Kazunori Sano, Ayumi Ogata, Ai Mizuki, Kenichi Mishima, Katsunori Iwasaki, Yukihiro Shoyama, Ryoji Nishimura, Michihiro Fujiwara, Antipsychotics improve Δ9-tetrahydrocannabinol-induced impairment of the prepulse inhibition of the startle reflex in mice, Pharmacology Biochemistry and Behavior, 10.1016/j.pbb.2006.05.018, 84, 2, 330-336, 2006.06, Recently, cannabinoid receptor agonists have been reported to impair prepulse inhibition (PPI) of the startle reflex. In the current study, we examined the effect of Δ9-tetrahydrocannabinol (THC), the principal psychoactive component of cannabis, on the PPI, and found that THC (10 mg/kg, i.p.) impaired the PPI concomitant with a decrease in the startle response. Antipsychotics such as haloperidol (0.3 mg/kg, i.p.) and risperidone (0.1 mg/kg, i.p.), which are potent dopamine D2 receptor antagonists, and SR141716 (10 mg/kg, i.p.), a CB1 cannabinoid receptor antagonist, reversed these THC-induced PPI deficits. Moreover, THC (10 mg/kg) increased dopamine (DA) release in the nucleus accumbens but not medial prefrontal cortex over a 50-100-min period (time of PPI test) after treatment, and SR141716 (10 mg/kg) reversed this increase in DA release induced by THC. These results suggest that dopaminergic hyperfunction in the nucleus accumbens may be involved in THC-induced PPI deficits..
112. Katsunori Iwasaki, Nobuaki Egashira, Izzettin Hatip-Al-Khatib, Yuki Akiyoshi, Takashi Arai, Yuki Takagaki, Takuya Watanabe, Kenichi Mishima, Michihiro Fujiwara, Cerebral ischemia combined with β-amyloid impairs spatial memory in the eight-arm radial maze task in rats, Brain Research, 10.1016/j.brainres.2006.04.073, 1097, 1, 216-223, 2006.06, β-Amyloid (Aβ), a major component of senile plaques in Alzheimer's disease, has been implicated in neuronal cell death, a characteristic feature of this condition. In our previous experiments using primary cultures of hippocampal neurons, Aβ treatment induced neuronal cell death, displaying morphological characteristics of apoptosis that was significantly enhanced by hypoxia. Based on these results, we developed a simple in vivo rat model of Alzheimer's disease using cerebral ischemia, instead of hypoxia, combined with continuous intracerebroventricular administration of Aβ. The combination of cerebral ischemia and Aβ administration, but not either treatment alone, significantly impaired spatial memory in an eight-arm radial maze. A microdialysis study showed that spontaneous release of acetylcholine (ACh) from the dorsal hippocampus had a tendency to decrease in response to Aβ treatment alone or the combination of ischemia and Aβ. High K+-evoked increase in ACh release had a tendency to be inhibited by either ischemia or Aβ treatment alone and was significantly inhibited by the combination of both. Moreover, combination of ischemia and Aβ induced apoptosis of pyramidal neurons in the CA1 region of the hippocampus. Donepezil, a drug currently in clinical use for Alzheimer's disease, improved the impairment of spatial memory induced by cerebral ischemia combined with Aβ. These findings suggest that ischemia is an important factor facilitating the symptoms of Alzheimer's disease, and this model may be useful for developing new drugs for the treatment of Alzheimer's disease..
113. Nobuaki Egashira, Akito Tanoue, Gozoh Tsujimoto, Kenichi Mishima, Yukio Takano, Katsunori Iwasaki, Michihiro Fujiwara, Vasopressin receptor knockout mice as an animal model of psychiatric disorders, Japanese Journal of Neuropsychopharmacology, 26, 2, 101-105, 2006.04, Arginine vasopressin (AVP) is a neurohypophyseal peptide best known as an antidiuretic hormone. AVP receptors have been classified into three subtypes: V1a, V1b, and V2 receptors. The V1a receptor (V1aR) and V1b receptor (V1bR) are widely distributed in the central nervous system, including the cortex and hippocampus. In the present study, we examined the performance of V1aR or V1bR knockout (KO) mice compared to wild-type (WT) mice in behavioral tests. V1aR KO mice exhibited impairments of spatial learning (eight-arm radial maze), prepulse inhibition (PPI) and social behavior in comparison to WT mice. On the other hand, V1bR KO mice also displayed impairments of PPI and social behavior. These results suggest that V1aR and V1bR may be involved in psychiatric disorders associated with impairments of sensorimotor gating and social behavior such as schizophrenia and autism..
114. Nobuaki Egashira, Jian Chen Li, Ai Mizuki, Keita Yamauchi, Tomoko Matsuda, Megumi Osajima, Michihiko Matsushita, Kenichi Mishima, Katsunori Iwasaki, Shuji Hara, Nobufumi Ono, Ryoji Nishimura, Toshihiro Nohara, Michihiro Fujiwara, Antagonistic effects of methanolic extract of Polygala telephioides on morphine responses in mice, Journal of Ethnopharmacology, 10.1016/j.jep.2005.08.056, 104, 1-2, 193-198, 2006.03, The present study was undertaken to investigate the antagonistic effects of the methanolic extract of Polygala telephioides (PT) on morphine responses in mice. Single administration of PT tended to antagonize the morphine-induced analgesia in a hot-plate test. Moreover, PT (300 mg/kg, p.o.) improved the morphine-induced memory impairment in an elevated plus maze test. However, PT alone had no effect on behaviors in the open-field, hot-plate and elevated plus maze tests. We investigated the effects of PT on naloxone-induced jumping (as withdrawal sign) in morphine-dependent mice. To induce dependence, mice were twice daily treated with morphine (10-45 mg/kg, s.c.) for 5 days. Co-administrations of PT (10, 100 and 300 mg/kg, p.o.) during repeated morphine treatments significantly suppressed the naloxone (10 mg/kg, i.p.)-induced jumping. However, the naloxone-induced jumping was not affected by a single large administration of PT on the 5th day. The inhibitory effect of PT on the naloxone-induced jumping was due to the development of dependence rather than expression of withdrawal sign. Moreover, single administration of PT (300 mg/kg, p.o.) decreased the morphine levels in plasma. These results indicate that PT may be useful in facilitating narcotic detoxification..
115. Tetsuro Murakami, Erwan Paitel, Takeshi Kawarabayashi, Masaki Ikeda, M. Azhar Chishti, Christopher Janus, Etsuro Matsubara, Atsushi Sasaki, Toshitaka Kawarai, Amie L. Phinney, Yasuo Harigaya, Patrick Horne, Nobuaki Egashira, Kenichi Mishima, Amanda Hanna, Jing Yang, Katsunori Iwasaki, Mitsuo Takahashi, Michihiro Fujiwara, Koichi Ishiguro, Catherine Bergeron, George A. Carlson, Koji Abe, David Westaway, Peter St. George-Hyslop, Mikio Shoji, Cortical neuronal and glial pathology in TgTauP301L transgenic mice
Neuronal degeneration, memory disturbance, and phenotypic variation, American Journal of Pathology, 10.2353/ajpath.2006.051250, 169, 4, 1365-1375, 2006.01, Recapitulation of tau pathologies in an animal model has been a long-standing goal in neurodegenerative disease research. We generated transgenic (TgTauP301L) mice expressing a frontotemporal dementia with parkinsonism linked to chromosome 17 (FTPD-17) mutation within the longest form of tau (2N, 4R). TgTauP301L mice developed florid pathology including neuronal pretangles, numerous Gallyas-Braak-positive neurofibrillary tangles, and glial fibrillary tangles in the frontotemporal areas of the cerebrum, in the brainstem, and to a lesser extent in the spinal cord. These features were accompanied by gliosis, neuronal loss, and cerebral atrophy. Accumulated tau was hyperphosphorylated, conformationally changed, ubiquitinated, and sarkosyl-insoluble, with electron microscopy demonstrating wavy filaments. Aged TgTauP301L mice exhibited impairment in hippocampally dependent and independent behavioral paradigms, with impairments closely related to the presence of tau pathologies and levels of insoluble tau protein. We conclude that TgTauP301L mice recreate the substantial phenotypic variation and spectrum of pathologies seen in FTDP-17 patients. Identification of genetic and/or environmental factors modifying the tau phenotype in these mice may shed light on factors modulating human tauopathies. These transgenic mice may aid therapeutic development for FTDP-17 and other diseases featuring accumulations of four-repeat tau, such as Alzheimer's disease, corticobasal degeneration, and progressive supranuclear palsy..
116. Nobuaki Egashira, Akiko Yano, Noriko Ishigami, Kenichi Mishima, Katsunori Iwasaki, Masayuki Fujioka, Michihiko Matsushita, Ryoji Nishimura, Michihiro Fujiwara, Investigation of mechanisms mediating 8-OH-DPAT-induced impairment of spatial memory
Involvement of 5-HT1A receptors in the dorsal hippocampus in rats, Brain Research, 10.1016/j.brainres.2005.10.103, 1069, 1, 54-62, 2006.01, The purpose of this study was to identify mechanisms that mediate the impairment of spatial memory induced by 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a 5-HT1A/5-HT7 receptor agonist, in the eight-arm radial maze in rats. WAY-100635 and NAN-190, 5-HT1A receptor antagonists, reversed the impairment of spatial memory induced by systemic injection of 8-OH-DPAT (1 mg/kg, i.p.). On the other hand, the α1-adrenoceptor antagonist prazosin and a selective 5-HT 7 receptor antagonist SB269970 had no effect on 8-OH-DPAT-induced impairment of spatial memory. Bilateral microinjection of 8-OH-DPAT (4 μg/side) impaired spatial memory when injected into the dorsal hippocampus (DH). Contrastingly, spatial memory was unaffected by microinjections of 8-OH-DPAT into the other six areas examined: ventral hippocampus (VH), central amygdaloid nucleus (ACE), lateral hypothalamus (LH), nucleus accumbens (NAc), and dorsal (DR) and median (MR) raphe nucleus. Furthermore, NAN-190 significantly reversed the impairment of spatial memory induced by intra-DH injection of 8-OH-DPAT. These findings suggest that 5-HT1A receptors in the DH play an important role in the mechanisms underlying the 8-OH-DPAT-induced impairment of spatial memory in rats..
117. Nobuaki Egashira, Yoshiaki Matsumoto, Kenichi Mishima, Katsunori Iwasaki, Masayuki Fujioka, Michihiko Matsushita, Yukihiro Shoyama, Ryoji Nishimura, Michihiro Fujiwara, Low dose citalopram reverses memory impairment and electroconvulsive shock-induced immobilization, Pharmacology Biochemistry and Behavior, 10.1016/j.pbb.2006.01.006, 83, 1, 161-167, 2006.01, Citalopram, a selective serotonin reuptake inhibitor (SSRI), is one of the most widely used antidepressants. Recently, citalopram has been reported to improve working memory in patients with depression, and psychotic symptoms and behavioral disturbances in patients with dementia. However, the possibility of using citalopram in the treatment of cognitive disorders has not received much attention. The present study investigated the effects of citalopram on scopolamine- and Δ9-tetrahydrocannabinol (THC)-induced impairment of spatial memory using an eight-arm radial maze and electroconvulsive shock (ECS)-induced immobilization (a behavioral model for the disturbance of consciousness). Low dose citalopram reversed both scopolamine- and THC-induced impairment of spatial memory, suppressed ECS-induced immobilization reversed the THC-induced decrease of acetylcholine (ACh) release in the dorsal hippocampus in vivo microdialysis, and enhanced tremors induced by oxotremorine, a muscarinic M1 receptor agonist. Taken together these findings suggest that low dose citalopram is useful for the treatment of memory deficits and consciousness disturbance..
118. Tomoaki Ikeda, Kenichi Mishima, Naoya Aoo, Kazuhiko Harada, Xin Liu An, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Tsuyomu Ikenoue, Rehabilitative training tasks improve spatial learning impairment in the water maze following hypoxic-ischemic insult in neonatal rats, Pediatric Research, 10.1203/01.pdr.0000190582.49589.14, 59, 1, 61-65, 2006.01, We recently reported that hypoxic-ischemic (HI) insult to the brain of 7-d-old rats resulted in a slowly progressive learning and memory disability, which started at around 5 wk after HI, a time frame that is representative of human adolescence. The purpose of the present study was to examine whether physical or mental exercises can prevent this late-onset, slowly progressing disability. Wistar rats were subjected to left carotid ligation followed by 2 h of hypoxic stress (8% O2 and 92% N2 at 33°C). Sham-control rats were subjected to the same procedure without ligation and hypoxic stress. Six weeks after the HI, the animals were divided into four groups: pretraining control, no training control, pretraining HI, and no training HI groups. We used the plus maze, eight-arm radial maze, and choice reaction time task as the rehabilitative training. Sixteen weeks after the HI, the water maze task was performed over 5 d to evaluate spatial learning ability; thereafter, cerebral morphology of the animals was examined. There were no differences in swimming length and latency between the pretraining control and no training control groups. Swimming length and latency in the pretraining HI group were significantly shorter and swifter than those in the no training HI group. The infarct areas on the left cerebral hemisphere were equivalent between pretraining HI and no training HI groups at each sectional slice. Rehabilitative training tasks prevented the neonatal Hi-induced late-onset slowly progressive learning and memory disability..
119. Izzettin Hatip-Al-Khatib, Katsunori Iwasaki, Yoshitaka Yoshimitsu, Takashi Arai, Nobuaki Egashira, Kenichi Mishima, Tomoaki Ikeda, Michihiro Fujiwara, Effect of oral administration of zanapezil (TAK-147) for 21 days on acetylcholine and monoamines levels in the ventral hippocampus of freely moving rats, British Journal of Pharmacology, 10.1038/sj.bjp.0706288, 145, 8, 1035-1044, 2005.12, Zanapezil (TAK-147 (3-[1benzylpiperdin-4-yl]-1-(2,3,4,5-tetrahydro-1 H-1-benzazepin-8-yl) propan-1-one fumarate)) is a selective acetylcholine (ACh) esterase inhibitor under investigation as a drug for Alzheimer's disease (AD) treatment. In this study, the effects of TAK-147 at 2 mg kg -1 p.o. for 21 days, compared to donepezil (E2020), on the levels of ACh, catecolamines and indoleamines were investigated in the ventral hippocampus (VH) of freely moving rats by microdialysis-high-performance liquid chromatography. The results revealed that the VH contains 92.05±21.97 fmol 20 μl -1 ACh and the following monoamines levels (pg 30 μl -1), norepinephrine (NE) 1.92±0.39, epinephrine (Epi) 1.91±0.183, 3-methoxy-4- hydroxyphenylglycol (MHPG) 11.53±3.22, normetanephrine 3.26±0.61, dopamine (DA) 0.77±0.23, 3,4-dihydroxyphenylacetic acid (DOPAC) 3.37±1.01, homovanillic acid (4-hydroxy-3-methoxyphenylacetic acid; HVA) 4.04±0.93, 3-methoxytyramine 0.64±0.13, serotonin (5-HT) 0.73±0.16 and 5-hydroxyindoleacetic acid (5-HIAA) 313.15±18.42. On the 21st day and prior to the last dose, TAK-147 increased ACh, Epi, DA and 5-HT, whereas E2020 increased MHPG, Epi and DA. Following the last dose, TAK-147 increased NE, whereas E2020 increased NE, ACh and 5-HT in addition to their effects prior to the last dose. TAK-147 decreased HVA:DA ratio, but only marginally decreased DOPAC:DA and 5-HIAA:5-HT ratios. On the other hand, E2020 decreased ratios of HVA:DA, DOPAC:DA (prior to the last dose), and 5-HIAA:5-HT (90-180 min after the last dose). Both drugs decreased MHPG:NE only at 180 min after the last dose. The results also showed that TAK-147 increased Epi:NE ratio prior to and for 120 min following the last dose, whereas E2020 increased the ratio only before the last dose. The present results show that TAK-147 at a subthreshold dose could differentially increase ACh and 5-HT, compared to MHPG increased by E2020. The last dose of each drug could extend their effects to other monoamines. The increase of the monoamines levels, in addition to that on the ACh, and decrease of their oxidation could be of value in the treatment of the AD, other dementic diseases and the cohort neurological disorders depending on the type of the monoamine underlying the disorder..
120. Nobuaki Egashira, Akito Tanoue, Fuminori Higashihara, Hiroko Fuchigami, Kazunori Sano, Kenichi Mishima, Yoshihiko Fukue, Hiroshi Nagai, Yukio Takano, Gozoh Tsujimoto, Jeanne Stemmelin, Guy Griebel, Katsunori Iwasaki, Tomoaki Ikeda, Ryoji Nishimura, Michihiro Fujiwara, Disruption of the prepulse inhibition of the startle reflex in vasopressin V1b receptor knockout mice
Reversal by antipsychotic drugs, Neuropsychopharmacology, 10.1038/sj.npp.1300784, 30, 11, 1996-2005, 2005.11, In the present study, we investigated whether mice lacking the arginine vasopressin (AVP) V1b receptor (V1bR) exhibit deficits of prepulse inhibition (PPI) of the startle reflex, reminiscent of the sensorimotor gating deficits observed in a large majority of schizophrenic patients. V1bR knockout (KO) mice displayed significantly reduced levels of PPI of the startle reflex. In addition to PPI deficits, V1bR KO mice showed increased acoustic startle response. However, acoustic startle response was not significantly correlated to the PPI of the startle reflex in V1bR KO mice. V1bR KO mice also showed a decrease in basal levels of extracellular dopamine (DA) in the medial prefrontal cortex, which is thought to be an important brain region for PPI. Moreover, PPI deficits observed in the V1bR KO mice are significantly reversed by atypical antipsychotics such as risperidone and clozapine but not by a typical neuroleptic haloperidol, like in schizophrenic patients. By contrast, we did not observe any significant differences between V1bR KO mice and wild-type mice in the open-field, light/dark, elevated plus maze, and forced swimming tests. The results of the present study indicate that V1bR may be involved in the regulation of PPI of the startle reflex. The V1bR has been considered an important molecular target for the development of antipsychotic drugs..
121. Jesmin I. Noor, Tomoaki Ikeda, Kenichi Mishima, Naoya Aoo, Sumie Ohta, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Tsuyomu Ikenoue, Short-term administration of a new free radical scavenger, edaravone, is more effective than its long-term administration for the treatment of neonatal hypoxic-ischemic encephalopathy, Stroke, 10.1161/01.STR.0000185653.49740.c6, 36, 11, 2468-2474, 2005.11, Background and Purpose - Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) is a new free radical scavenger that is used for the treatment of adult acute cerebral infarction in Japan. We examined the effect of edaravone on the optimal duration of treatment, the long-term effect on the brain, and the effect on learning and memory disability in a rat model of neonatal hypoxic-ischemic encephalopathy. Methods - Seven-day-old Wistar rats were subjected to left common carotid artery ligation then 2 hours of hypoxic-ischemic insult or sham operation. Edaravone was administered intraperitoneally (9 mg/kg) after hypoxic-ischemic insult every 24 hours for 2, 5, or 10 consecutive days. The neuroprotective effect of edaravone was evaluated by behavioral test and histological analysis. Results - Two-day treatment with edaravone significantly gave protection to the learning and memory capability, as well as morphological recovery compared with control rats. Five-day treatment showed morphological improvement but no behavioral improvement. In contrast, 10-day treatment did not show either morphological or behavior improvement. Conclusions - These findings indicate that edaravone is a promising candidate as a treatment of choice for neonatal hypoxic-ischemic encephalopathy, when its use is limited to the acute phase after hypoxia-ischemia..
122. Nobuaki Egashira, Katsunori Iwasaki, Akihiko Takashima, Takuya Watanabe, Hideyuki Kawabe, Tomomi Matsuda, Kenichi Mishima, Shozo Chidori, Ryoji Nishimura, Michihiro Fujiwara, Altered depression-related behavior and neurochemical changes in serotonergic neurons in mutant R406W human tau transgenic mice, Brain Research, 10.1016/j.brainres.2005.08.004, 1059, 1, 7-12, 2005.10, Mutant R406W human tau was originally identified in frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) and causes a hereditary tauopathy that clinically resembles Alzheimer's disease (AD). In the current study, we examined the performance of R406W transgenic (Tg) mice in the forced swimming test, a test with high predictivity of antidepressant efficacy in human depression, and found an enhancement of the immobility time. In contrast, the motor function and anxiety-related emotional response of R406W Tg mice were normal. Furthermore, a selective serotonin reuptake inhibitor (SSRI), fluvoxamine (100 mg/kg, p.o.), significantly reduced this enhancement of the immobility time, whereas a noradrenaline reuptake inhibitor, desipramine, had no effect. In an in vivo microdialysis study, R406W Tg mice exhibited a significantly decreased extracellular 5-hydroxyindoleacetic acid (5-HIAA) level in the frontal cortex and also exhibited a tendency toward a decreased extracellular 5-hydroxytryptamine (5-HT) level. Moreover, fluvoxamine, which reduced the enhancement of the immobility time, significantly increased the extracellular 5-HT level in R406W Tg mice. These results suggest that R406W Tg mice exhibit changes in depression-related behavior involving serotonergic neurons and provide an animal model for investigating AD with depression..
123. Fengling Pu, Kenichi Mishima, Nobuaki Egashira, Yuki Akiyoshi, An xin Liu, Kazunori Sano, Keiichi Irie, Daisuke Ishibashi, Izzettin Hatip-Al-Khatib, Kiyo Iwasaki, Kouji Kurauchi, Katsunori Iwasaki, Michihiro Fujiwara, Post-ischemic treatment with Toki-shakuyaku-san (Tang-Gui-Shao-Yao-San) prevents the impairment of spatial memory induced by repeated cerebral ischemia in rats, American Journal of Chinese Medicine, 10.1142/S0192415X05003077, 33, 3, 475-489, 2005.07, Previously we have reported that Toki-shakuyaku-san (TSS) ameliorated the impairment of spatial memory induced by single cerebral ischemia (1 × 10 minutes) and scopolamine, a muscarinic receptor antagonist. In this experiment, we studied the effect of TSS on repeated cerebral ischemia (2 × 10 minutes, 1-hour interval) induced impairment of spatial memory and neuronal injury in rats. The 8-day post-ischemic treatment with TSS (30-300 mg/kg) was administered p.o. once per day. TSS dose-dependently prevented the impairment of spatial memory, neuronal death and TUNEL positive cells induced by repeated cerebral ischemia. In order to determine the mechanism of TSS, we also studied the effect of TSS on GluR2 mRNA, one of the glutamate α-amino-3- hydroxy-5-methyl-4-isoxazole (AMPA) receptor subunits. Repeated cerebral ischemia significantly decreased GluR2 flop mRNA at 1 and 3 days after the occlusion. TSS (300 mg/kg) significantly suppressed the decrease in GluR2 flop at 3 days after repeated cerebral ischemia. These results suggested that the TSS has neuroprotective action which may be indirectly mediated by the AMPA receptor, and TSS may be beneficial for the treatment of cerebrovascular dementia..
124. Kenichi Mishima, Kazuhide Hayakawa, Kohji Abe, Tomoaki Ikeda, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Cannabidiol prevents cerebral infarction via a serotonergic 5-hydroxytryptamine1A receptor-dependent mechanism, Stroke, 10.1161/01.STR.0000163083.59201.34, 36, 5, 1071-1076, 2005.05, Background and Purpose - Cannabidiol has been reported to be a neuroprotectant, but the neuroprotective mechanism of cannabidiol remains unclear. We studied the neuroprotective mechanism of cannabidiol in 4-hour middle cerebral artery (MCA) occlusion mice. Methods - Male MCA occluded mice were treated with cannabidiol, abnormal cannabidiol, anandamide, methanandamide, cannabidiol plus capsazepine, and cannabidiol plus WAY100135 before and 3 hours after MCA occlusion. The infarct size was determined after 24 hours (2,3,5-triphenyltetrazolium chloride staining). Cerebral blood flow (CBF) was measured at, before and 1, 2, 3, and 4 hours after MCA occlusion. Results - Cannabidiol significantly reduced the infarct volume induced by MCA occlusion in a bell-shaped curve. Similarly, abnormal cannabidiol but not anandamide or methanandamide reduced the infarct volume. Moreover, the neuroprotective effect of cannabidiol was inhibited by WAY100135, a serotonin 5-hydroxytriptamine 1A (5-HT1A) receptor antagonist but not capsazepine a vanilloid receptor antagonist. Cannabidiol increased CBF to the cortex, and the CBF was partly inhibited by WAY100135 in mice subjected to MCA occlusion. Conclusions - Cannabidiol and abnormal cannabidiol reduced the infarct volume. Furthermore, the neuroprotective effect of cannabidiol was inhibited by WAY100135 but not capsazepine, and the CBF increased by cannabidiol was partially reversed by WAY100135. These results suggested that the neuroprotective effect of cannabidiol may be related to the increase in CBF through the serotonergic 5-HT1A receptor..
125. Nobuaki Egashira, Katsunori Iwasaki, Yuki Akiyoshi, Yuki Takagaki, Izzettin Hatip-Al-Khatib, Kenichi Mishima, Kouji Kurauchi, Tomoaki Ikeda, Michihiro Fujiwara, Protective effect of Toki-shakuyaku-san on amyloid β25-35- induced neuronal damage in cultured rat cortical neurons, Phytotherapy Research, 10.1002/ptr.1671, 19, 5, 450-453, 2005.05, Amyloid β protein (Aβ) is the major component of senile plaques, the pathological hallmark of the neurodegeneration associated with Alzheimer's disease (AD). This study investigated the effect of Toki-shakuyaku-san (TSS), a traditional medicine, on Aβ25-35-induced neuronal death and lipid peroxidation assessed by measuring lactate dehydrogenase (LDH) and malondialdehyde (MDA), respectively. Aβ25-35 at 10 μM induced neuronal damage and increased the LDH and MDA. TSS at concentrations of 100 and 300 μg/mL significantly reduced the Aβ25-35-induced neuronal death and the lipid peroxidation. These results suggest that TSS has a protective effect against Aβ25-35-induced neuronal damage. TSS may be beneficial for the treatment of AD..
126. Kenichi Mishima, Tomoaki Ikeda, Naoya Aoo, Nobuhiko Takai, Sentaro Takahashi, Nobuaki Egashira, Tsuyomu Ikenoue, Katsunori Iwasaki, Michihiro Fujiwara, Hypoxia-ischemic insult in neonatal rats induced slowly progressive brain damage related to memory impairment, Neuroscience Letters, 10.1016/j.neulet.2004.11.055, 376, 3, 194-199, 2005.03, The present study was designed to determine potential associations between the brain damage induced by hypoxic-ischemic (HI) insult and spatial learning impairment in an eight-arm radial maze task. We first determined the pathological outcomes after 2, 5, 9, and 17 weeks of recovery following the HI insult. The results show that the brain damage progressed from 2 up to 17 weeks of recovery. To clarify the time course of the brain damage changes, we investigated the histological changes of the same individual with magnetic resonance imaging (MRI) after 5, 9, and 57 weeks of recovery following the HI insult. The MRI changes were similar to the histological changes, and the brain damages were exacerbated in the contralateral hemisphere after 57 weeks of recovery following the HI insult. To investigate whether alteration in brain function was correlated with MRI and histological changes, the rats were made to find their way through an eight-arm radial maze was performed at either 7th or 16th weeks of recovery. According to the results, the spatial learning impairments of rats in the maze starting at 16 weeks of recovery were more severe than those at 7 weeks of recovery, indicating that the impairments were progressive and depended on the degree of brain damage. The results of the present study are the first demonstration that the evolutional and specific brain damage following the HI insult is slowly and progressively exacerbated to the contralateral hemisphere and rats who experience the HI are at risk for showing a late impairment of brain function..
127. Tomoaki Ikeda, Kenichi Mishima, Naoya Aoo, An Xin Liu, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Tsuyomu Ikenoue, Dexamethasone prevents long-lasting learning impairment following a combination of lipopolysaccharide and hypoxia-ischemia in neonatal rats, American Journal of Obstetrics and Gynecology, 10.1016/j.ajog.2004.12.048, 192, 3, 719-726, 2005.01, Objective: There are no established therapies for preventing or rescuing perinatal infection or inflammation-induced perinatal brain damage. We administered dexamethasone (DEX), a synthetic corticosteroid anti-inflammatory drug, to neonatal rats in a model of such damage induced by a combination of lipopolysaccharide (LPS) and hypoxia-ischemia (HI), which produces characteristic histologic and behavioral abnormalities. Study design: Four hours after the injection of LPS (1 mg/kg, i.p.), 7-day-old Wistar rat pups were subjected to unilateral HI for 1 hour according to Levine's procedure. Injections of 0.5 mg/kg of dexamethasone (DEX-treated group, n = 15) or saline (saline-treated group, n = 15) were given 4 hours before HI. A sham-operated control group received neither LPS nor HI (n = 15). We chose rats of this age because their stage of brain maturation is similar to the human neonate. Over the 7 to 16 weeks after treatment, a choice reaction time (CRT) task was used for assessment of attention processes in each group, an 8-arm radial maze task was used to test short-term memory, and a water maze task was used to test long-term memory. In the CRT task, the reward food was released when the tested animal correctly pressed a lever on the side of an illuminating lamp. The correct and incorrect lever pressings were counted. In the 8-arm radial maze task, rats were allowed to move freely, seeking a reward of food placed at the end of 1 arm. An error was defined as the choice of an arm that had already been visited. In the water maze, rats had to swim to seek a concealed platform as aversive escape motivation. At 19 weeks, the rats were euthanized, the brain was removed, sectioned coronally, and the volume of each part was measured. Results: The striatum, cortex, and hippocampus showed reductions in volume in the saline-treated group (42.7%, 49.2%, and 34.9% decreases compared with the sham-operated controls, respectively), but this was not observed in the DEX-treated group. All learning and memory processes were impaired with the combination of LPS and HI treatment, but these deficits were almost completely prevented by DEX treatment. Conclusion: Dexamethasone is a promising candidate for prevention of infection and inflammation-induced perinatal brain damage. The impact of dexamethasone identifies potential therapeutic pathways once the mechanism of dexamethasone's protection is determined..
128. Fengling Pu, Kenichi Mishima, Keiichi Irie, Nobuaki Egashira, Daisuke Ishibashi, Yoshiaki Matsumoto, Tomoaki Ikeda, Katsunori Iwasaki, Hajime Fujii, Kenichi Kosuna, Michihiro Fujiwara, Differential effects of buckwheat and kudingcha extract on neuronal damage in cultured hippocampal neurons and spatial memory impairment induced by scopolamine in an eight-arm radial maze, Journal of Health Science, 10.1248/jhs.51.636, 51, 6, 636-644, 2005.01, We have reported the neuroprotection provided by an extract of buckwheat (BWE, Fagopyrum esculentum Moench) on neuronal damage in the repeated cerebral ischemia model and demonstrated that BWE inhibited the excess glutamate release induced by repeated cerebral ischemia, suggesting that BWE had a free radical-scavenging in addition to anti-glutamate action. In the present study, we studied the neuroprotective effects of Kudingcha extract (KDE, Ligustrum purpurascens Y. C.) on scavenging by the 2,2-diphenyl-1-picylhydrazyl (DPPH) radical in primary cultured hippocampal neurons, and on spatial memory impairment induced by scopolamine in an eight-arm radial maze in comparison with BWE. The effects of KDE (0.01-1 mg/ml) were more potent than those of BWE (0.01-1 mg/ml) in scavenging the DPPH radical (1 mM). KDE (100 μg/ml) prevented the cell damage induced by glutamate (300 μM) or kainate (1 mM), which was more potent than BWE (100 μg/ml), but BWE suppressed the cellular damage induced by β-amyloid(25-35) (20 μM) more potently than KDE (100 μg/ml). BWE (600 mg/kg), but not KDE, significantly suppressed the increase in errors induced by scopolamine (0.5 mg/kg i.p.) in the eight-arm radial maze. The results suggest that BWE may protect against cholinergic dysfunction and that KDE protects more effectively against glutaminergic dysfunction..
129. Shinji Katsuragi, Tomoaki Ikeda, Isao Date, Tetsuro Shingo, Takao Yasuhara, Kenichi Mishima, Naoya Aoo, Kazuhiko Harada, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Tsuyomu Ikenoue, Implantation of encapsulated glial cell line-derived neurotrophic factor-secreting cells prevents long-lasting learning impairment following neonatal hypoxic-ischemic brain insult in rats, American Journal of Obstetrics and Gynecology, 10.1016/j.ajog.2005.01.014, 192, 4, 1028-1037, 2005.01, Objective: Implantation of encapsulated glial cell line-derived neurotrophic factor-secreting cells into brain parenchyma reduces histological brain damage following hypoxic-ischemic stress in neonatal rats. We examined the effect of glial cell line-derived neurotrophic factors on long-term learning and memory impairment and morphological changes up to 18 weeks after hypoxic-ischemic stress in neonatal rats. Study design: Baby hamster kidney cells were transfected with expression vector either including (glial cell line-derived neurotrophic factor-hypoxic-ischemic group; n = 10) or not including (control-hypoxic-ischemic group; n = 8) human glial cell line-derived neurotrophic factor cDNA, encapsulated in semipermeable hollow fibers, and implanted into the left brain parenchyma of 7-day-old Wistar rats. Two days after implantation the rats received hypoxic-ischemic stress, and their behavior was then examined in several learning tasks: the 8-arm radial maze, choice reaction time, and water maze tasks, which examine short-term working memory, attention process, and long-term reference memory, respectively. The rats were killed 18 weeks after the hypoxic-ischemic insult for evaluation of brain damage. Two additional control groups were used: the control group (n = 15), which underwent no treatment, and the glial cell line-derived neurotrophic factor group (n = 6), which underwent implantation of the glial cell line-derived neurotrophic factor capsule but did not undergo hypoxic-ischemic stress. Results: The decrease in the size of the cerebral hemisphere was significantly less in the glial cell line-derived neurotrophic factor-hypoxic-ischemic group, compared with the control-hypoxic-ischemic group, and improved performance was observed in all three tasks for the glial cell line-derived neurotrophic factor-hypoxic-ischemic group: for the control-hypoxic-ischemic group versus the glial cell line-derived neurotrophic factor-hypoxic-ischemic group, respectively, in the 8-arm radial maze test, average number of correct choices was 6.2 ± 0.1 versus 6.9 ± 0.1 (P < .01); in the choice reaction time test, average reaction time for a correct response was 2.35 ± 0.1 seconds versus 1.97 ± 0.09 seconds (P < .01); in the water maze test, average swimming length was 1120.0 ± 95.2 cm versus 841.6 ± 92.1 cm (P < .01). All results for the glial cell line-derived neurotrophic factor group were similar to those for the control group. Conclusion: Glial cell line-derived neurotrophic factor treatment is effective in not only reducing brain damage but also inhibiting learning and memory impairment, following hypoxic-ischemic insult in neonatal rats. No adverse effects in learning and memory tests were observed in the glial cell line-derived neurotrophic factor group..
130. Michihiko Matsushita, Nobuaki Egashira, Satoko Harada, Ryoko Okuno, Kenichi Mishima, Katsunori Iwasaki, Ryoji Nishimura, Michihiro Fujiwara, Perospirone, a novel antipsychotic drug, inhibits marble-burying behavior via 5-HT1A receptor in mice
Implications for obsessive-compulsive disorder, Journal of Pharmacological Sciences, 10.1254/jphs.FP0050144, 99, 2, 154-159, 2005, Perospirone is a novel atypical antipsychotic drug with dopamine (DA) D2- and serotonin (5-hydroxytryptamine, 5-HT) 5-HT 2A-receptor antagonist, and 5-HT1A-receptor agonist properties. In the present study, we examined the effect of perospirone on marble-burying behavior, which has been considered an animal model of obsessive-compulsive disorder (OCD), compared with the effects of other antipsychotics such as haloperidol and risperidone. Perospirone at a dose of 10 mg/kg (p.o.) inhibited marble-burying behavior without affecting the locomotor activity in mice. On the other hand, haloperidol (0.1 mg/kg, i.p.) and risperidone (1 mg/kg, p.o.) showed significant suppression of locomotor activity at the dose that inhibited marble-burying behavior. Furthermore, the inhibition of marble-burying behavior by perospirone was antagonized by WAY100135 (10 mg/kg, i.p.), a selective 5-HT1A-receptor antagonist. WAY100135 at the same dose also antagonized the inhibition of marble-burying behavior by 8-OH-DPAT (3 mg/kg, i.p.), a selective 5-HT1A-receptor agonist. These findings suggest that perospirone may exhibit anti-OCD activity in clinical use and that 5-HT1A-receptor agonistic activity may be involved in the inhibition of marble-burying behavior by perospirone..
131. Tomoaki Ikeda, Kenichi Mishima, Naoya Aoo, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Tsuyomu Ikenoue, Combination treatment of neonatal rats with hypoxia-ischemia and endotoxin induces long-lasting memory and learning impairment that is associated with extended cerebral damage, American Journal of Obstetrics and Gynecology, 10.1016/j.ajog.2004.04.039, 191, 6, 2132-2141, 2004.12, We assessed the long-term effects of perinatal hypoxia-ischemia and endotoxin on attention and short- and long-term memory in neonatal rats with the use of behavioral tasks and brain histologic results. Four hours after injections of lipopolysaccharide (1 mg/kg, intraperitoneally) or saline solution, 7-day-old Wistar rat pups were subjected to unilateral hypoxia-ischemia for 1 hour. We studied 4 groups: controls (n = 43 rats), lipopolysaccharide alone (n = 12 rats), hypoxia-ischemia alone (n = 29 rats), and combined lipopolysaccharide + hypoxia-ischemia treatment (n = 34 rats). Seven to 16 weeks after the treatment, we measured attention with a choice reaction time task, short-term memory with an 8-arm radial maze task, and long-term memory with a water maze task. At 19 weeks of age, the brain was removed, fixed, and sectioned coronally; and the volume of each part was measured. A loss of volume in the hippocampus was observed in the lipopolysaccharide, hypoxia-ischemia, and lipopolysaccharide + hypoxia-ischemia groups; a loss of striatum was observed in the hypoxia-ischemia and lipopolysaccharide + hypoxia-ischemia groups, but loss of cortex was observed only in the lipopolysaccharide + hypoxia-ischemia group. The lipopolysaccharide, hypoxia-ischemia, and lipopolysaccharide + hypoxia-ischemia groups showed significantly poorer performance (attention deficit) than controls in the choice reaction time task. Correct choices decreased, and error increased in the lipopolysaccharide + hypoxia-ischemia group compared with the other groups in the radial maze task, which shows short-term memory impairment. Swimming distance was significantly greater in the hypoxia-ischemia and lipopolysaccharide + hypoxia-ischemia groups than in the other 2 groups in the water maze test, which shows long-term memory impairment. Combined lipopolysaccharide and hypoxia-ischemia treatment synergistically induced short-term memory impairment that is associated with loss of cortical volume..
132. Katsunori Iwasaki, Izzettin Hatip-Al-Khatib, Nobuaki Egashira, Yuki Akiyoshi, Takashi Arai, Kenichi Mishima, Yuki Takagaki, Keiichiro Inui, Michihiro Fujiwara, Ovariectomy combined with amyloid β1-42 impairs memory by decreasing acetylcholine release and α7nAChR expression without induction of apoptosis in the hippocampus CA1 neurons of rats, Neurotoxicity Research, 10.1007/BF03033440, 6, 4, 299-309, 2004.12, In this study, the effect of ovariectomy and amyloid P1-42 (Aβ1-42)on eight-armed radial maze performance, acetylcholine (ACh) release, α7nACh receptor (α7nAChR), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) expression, and apoptosis of CA1 neurons in the dorsal hippocampus were investigated in rat. The results showed that the dorsal hippocampus of sham rats contains 136.7 ± 16.7 to 160.4 ± 21.1 fmol/μl ACh, and respective 201 ± 22.9 and 416.6 ± 66.3 expression of mRNA for α7nAChR and GAPDH. Ovariectomy alone, after 4 weeks, did not impair memory, and neither induced apoptosis nor changed the basal ACh release. On the other hand, Aβ1-42 (600 pmol/10 μl/ body/day i.c.v. for 7 days) impaired memory, an effect characterized by increased error choices and reduced (50-59%) ACh release, but only with slight apoptosis. Moreover, ovariectomy combined with Aβ1-42 induced memory impairment characterized by decreased numbers of correct choices and increased numbers of errors. This effect was accompanied by a decrease of the basal ACh level (67%), α7nAChR mRNA expression (52%) and α7nAChR/GAPDH ratio (44%) without induction of apoptosis in the dorsal hippocampus. The high K+-evoked ACh release was not altered in ovariectomized rats, but was decreased by Aβ1-42 (43%) and ovariectomy + Aβ1-42 (80%). These results suggest that ovariectomy-induced hormonal deprivation after 4 weeks, when accompanied by Aβ1-42 accumulation in the dorsal hippocampus, could impair memory by decreasing ACh release and α7nAChR expression without inducing apoptosis in the CA1 field of the dorsal hippocampus..
133. Keiichiro Inui, Nobuaki Egashira, Kenichi Mishima, Akiko Yano, Yoshiaki Matsumoto, Nobuyoshi Hasebe, Kohji Abe, Kazuhide Hayakawa, Tomoaki Ikeda, Katsunori Iwasaki, Michihiro Fujiwara, The serotonin1A receptor agonist 8-OHDPAT reverses Δ9-tetrahydrocannabinol-induced impairment of spatial memory and reduction of acetylcholine release in the dorsal hippocampus in rats, Neurotoxicity Research, 10.1007/BF03033218, 6, 2, 153-157, 2004.12, We studied the effects of 8-hydroxy-2-(di-n-propylamino) tetralin (8-OHDPAT), a 5-HT1A receptor agonist, on both Δ9-tetrahydrocannabinol-induced spatial memory impairment in an 8-arm radial maze, and the reduction of acetylcholine release in the dorsal hippocampus as assessed by in vivo microdialysis in rats. A 6 mg/kg i.p. dose of Δ9-tetrahydrocannabinol impaired spatial memory in the 8-arm radial maze and decreased the acetyl-choline release in the dorsal hippocampus. 8-OHD-PAT, at very low doses of 0.1-0.3 μg/kg, reversed both the impairment of spatial memory and the decrease in acetylcholine release induced by Δ9-tetrahydrocannabinol. These findings suggest that low doses of 8-OHDPAT may improve Δ9 -tetrahy-drocannabinol-induced impairment of spatial memory by enhancing acetylcholine release in the dorsal hippocampus..
134. Kazuhide Hayakawa, Kenichi Mishima, Kohji Abe, Nobuyoshi Hasebe, Fumie Takamatsu, Hiromi Yasuda, Tomoaki Ikeda, Keiichiro Inui, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Cannabidiol prevents infarction via the non-CBI cannabinoid receptor mechanism, NeuroReport, 10.1097/00001756-200410250-00016, 15, 15, 2381-2385, 2004.10, Cannabidiol, a non-psychoactive constituent of cannabis, has been reported as a neuroprotectant. Cannabidiol and Δ 9-tetrahydrocannabinol, the primary psychoactive constituent of cannabis, significantly decreased the infarct volume at 4 h in the mouse middle cerebral artery occlusion model. The neuroprotective effects of Δ 9-tetrahydrocannabinol but not cannabidiol were inhibited by SRI41716, a cannabinoid CBI receptor antagonist, and were abolished by warming of the animals to the levels observed in the controls. Δ 9-Tetrahydrocannabinol significantly decreased the rectal temperature, and the hypothermic effect was inhibited by SRI41716. These results surely show that the neuroprotective effect of Δ 9- tetrahydrocannabinol are via a CBI receptor and temperature-dependent mechanisms whereas the neuroprotective effects of cannabidiol are independent of CBI blockade and of hypothermia..
135. Izzettin Hatip-Al-Khatib, Nobuaki Egashira, Kenichi Mishima, Katsunori Iwasaki, Kiyo Iwasaki, Kouji Kurauchi, Keiichiro Inui, Tomoaki Ikeda, Michihiro Fujiwara, Determination of the effectiveness of components of the herbal medicine Toki-Shakuyaku-San and fractions of Angelica acutiloba in improving the scopolamine-induced impairment of rat's spatial cognition in eight-armed radial maze test, Journal of Pharmacological Sciences, 10.1254/jphs.FPJ04015X, 96, 1, 33-41, 2004.09, The improving effects of various components of Toki-Shakuyaku-San (TSS) and fractions isolated from Angelica acutiloba Radix (Toki) on scopolamine-induced spatial memory impairment were investigated in eight-armed radial maze. The scopolamine-induced memory impairment was characterized by prominent increase of error choices in addition to decreased correct choices. Toki, Cnidium officinale Rhizoma (Senkyu), Poria cocos Hoelen (Bukuryo), Alisma orientale Rhizoma (Takusha), and Atractylodes lancea Rhizoma (Sojutsu) increased the correct choices, while only the Toki, Sojutsu, and Takusha decreased the error choices. No effect was produced by Paeonia lactiflora Radix (Shakuyaku). Investigation of effects of fractions isolated from Toki revealed that its activity mainly resided in the butanol layer and its contents of N-methyl-β-carboline-3-carboxamide and amines. Moreover, the alkaloid, internal and external solutions (containing poly-, di-, and monosaccharides) obtained by dialysis with Visking cellophane tubing also improved the memory. However, no improving properties were detected for methanol and hexanol layers, L-(-)-tryptophan, L-arginine, L-(-)-lysine, and choline chloride. The results showed that the TSS components could improve the reference and working memory impaired by scopolamine. The improving effect of TSS is produced greatly by the Toki component, the activity of which was greatly produced by the fraction extracted by butanol..
136. Izzettin Hatip-Al-Khatib, Katsunori Iwasaki, Eun Hee Chung, Nobuaki Egashira, Kenichi Mishima, Michihiro Fujiwara, Inhibition of poly (ADP-ribose) polymerase and caspase-3, but not caspase-1, prevents apoptosis and improves spatial memory of rats with twice-repeated cerebral ischemia, Life Sciences, 10.1016/j.lfs.2004.05.014, 75, 16, 1967-1978, 2004.09, The effect of inhibition of PARP [(poly (ADP-ribose) polymerase], caspase-3 and caspase-1 on twice-repeated ischemia-induced apoptosis and memory impairment were examined. The twicerepeated ischemia was induced by four-vessel occlusion method in which a 10 min ischemic episode was repeated once after 60 min. The spatial memory was assessed using 8-arm radial maze. The results of this study showed that the repeated ischemia impaired memory and induced apoptosis in hippocampus CA1 field after 7 days. Moreover, 3-aminobezamide (10 mg/kg i.v.), a PARP inhibitor, and Ac-DEVD-CHO (8.4 μg/5 μL i.c.v., bilaterally), a caspase-3 inhibitor, decreased apoptosis by 45% and 58% respectively. Both drugs reduced the error choices, but 3-aminobezamide additionally increased the correct choices and improved the memory when either drug was injected immediately after the ischemic insult. The results also showed that inhibition of interleukin-1β-converting enzyme, ICE (caspase-1) by Z-ASP-DCB-CH2 (100 μg/kg i.c.v., bilaterally) neither decreased apoptosis (13% reduction) nor improved memory of the ischemic rats. These results suggest that direct inhibition of PARP and caspase-3, but not of caspase-1, prevents apoptosis and improves spatial memory impaired by repeated ischemia..
137. Kenichi Mishima, Akito Tanoue, Masakazu Tsuda, Nobuyoshi Hasebe, Yoshihiko Fukue, Nobuaki Egashira, Yukio Takano, Hiro O. Kamiya, Gozoh Tsujimoto, Katsunori Iwasaki, Michihiro Fujiwara, Characteristics of behavioral abnormalities in α1d- adrenoceptors deficient mice, Behavioural Brain Research, 10.1016/j.bbr.2003.10.038, 152, 2, 365-373, 2004.07, To investigate the functional role of α1d-adrenergic receptor (α1d-AR) in the CNS, we have generated mutant mice lacking the α1d-AR using a gene targeting approach and examined in detail the effects of α1d-AR knockout mice on motor function, sensory function, and learning and memory. α1d-AR knockout mice showed better motor coordination at the highest rotating speed of the rotarod performance and stronger muscle tone using the traction meter, but their locomotor activity and swimming ability in the water maze were not affected. In the water maze requiring reference memory, α1d-AR knockout mice showed normal spatial learning. In the Y-maze task requiring working memory or attention, α1d-AR knockout mice displayed an impaired spontaneous alternation performance. The α1d-AR knockout mice tended to display lower levels of acoustic startle responses than the wild-type group at lower pulse intensities, although the acoustic prepulse inhibition was not impaired in the α1d-AR knockout mice. Furthermore, the NMDA receptor antagonist, MK-801-induced deficits of acoustic prepulse inhibition were not observed in the α1d-AR knockout mice. These results clearly demonstrate that the α1d-AR receptor plays an important role in the process of auditory sensory function, attention or working memory rather than reference memory, and the sensorimotor gating deficits induced by the NMDA receptor antagonist..
138. Izzettin Hatip-Al-Khatib, Arai Takashi, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Comparison of the effect of TAK-147 (zanapezil) and E-2020 (donepezil) on extracellular acetylcholine level and blood flow in the ventral hippocampus of freely moving rats, Brain Research, 10.1016/j.brainres.2004.03.067, 1012, 1-2, 169-176, 2004.06, The effects of zanapezil (TAK-147) and donepezil (E2020) on extracellular acetylcholine (ACh) levels were investigated by HPLC-microdialysis of ventral hippocampus (VH) in freely moving intact rats. The results showed that the basal ACh release rate in the VH is 116.7±12.4 to 158.4±22.86 fmol/20 μl. At 2, 5 and 10 mg/kg, single p.o., each drug increased ACh level by 9.4%, 106.5%, 50.8% (TAK-147) and 14.8%, 76.1%, 120.94% (E2020), respectively. The ED50 values were 4.52 mg/kg (1.43-14.29; R=0.52) and 4.07 mg/kg (1.77-9.37; R=0.985) for TAK-147 and E2020, respectively. Analysis of data revealed that the relative TAK-147/E2020 potency ratio is 0.773, but the effect of E2020 was accompanied by more prominent skeletal muscle fasciculation, gnawing, increased defecation and to lesser extent salivation. Moreover, the significant effect of TAK-147 was observed earlier (20 min) than E2020 (60 min). In this study, we also investigated the effect of both drugs at dose of 5 mg/kg p.o. on blood flow in the VH using Laser Doppler Flowmetry. The results showed that the average blood flow rate in the VH is 6.5±0.9 ml/min/100 g. TAK-147 did not change blood flow, but E2020 increased blood flow in a biphasic manner. The first increment was obtained between 5 and 40 min (11.5±2.2 to 12.7±2.2 ml/min/100 g), and the second one 80-105 min (10.7±1.6 to 13.4±3.6 ml/min/100 g). In conclusion, the present results indicate that both TAK-147 and E2020 increase ACh level in the VH. E2020 showed greater potency than TAK-147, but it induced more fasciculation and other side effects than TAK-147. Moreover, the blood flow increasing properties of E2020 could be beneficial in some patients with Alzheimer' disease especially those with chronic vascular dementia, but at the same time, it could also indicate less specific ACh increasing activity than TAK-147 and higher risk of cerebral hemorrhage. On the other hand, the fast and specific effect of TAK-147 may be useful for cure of early stages of Alzheimer's disease (AD)..
139. Nobuaki Egashira, Kazuhide Hayakawa, Kenichi Mishima, Hitomi Kimura, Katsunori Iwasaki, Michihiro Fujiwara, Neuroprotective effect of γ-glutamylethylamide (theanine) on cerebral infarction in mice, Neuroscience Letters, 10.1016/j.neulet.2004.03.046, 363, 1, 58-61, 2004.06, In the present study, we examined the neuroprotective effect of γ-glutamylethylamide (theanine) on the ischemic brain damage in a middle cerebral artery occlusion model in mice. Theanine was injected i.p. 3 h after the occlusion or immediately before and 3 h after the occlusion. Theanine (1 mg/kg) significantly decreased the size of the cerebral infarcts 1 day after the occlusion. In contrast, theanine did not affect the cerebral blood flow, brain temperature and physiological variables (pH, pCO2, pO2 and hematocrit) in this model. These results suggest that theanine directly provides neuroprotection against focal cerebral ischemia and may be clinically useful for preventing cerebral infarction..
140. Kenichi Mishima, Tomoaki Ikeda, Tetsuya Yoshikawa, Naoya Aoo, Nobuaki Egashira, Yi X. Xia, Tsuyomu Ikenoue, Katsunori Iwasaki, Michihiro Fujiwara, Effects of hypothermia and hyperthermia on attentional and spatial learning deficits following neonatal hypoxia-ischemic insult in rats, Behavioural Brain Research, 10.1016/j.bbr.2003.08.018, 151, 1-2, 209-217, 2004.05, We previously reported that rats exposed to neonatal hypoxic-ischemic (HI) insult showed selective and long-lasting learning and memory impairments in the plus maze, 8-arm radial maze, choice reaction time (CRT) task, and water maze, and that they showed severe brain injury to areas such as parietal cortex, hippocampus, striatum and thalamus. In this study, we examined the effects of hypothermia and hyperthermia on learning and memory deficits following neonatal HI insult. Seven-day-old Wistar rats were subjected to left carotid artery ligation followed by 2h of hypoxia (8% O2/92% N2) under three different temperature conditions: 27°C (hypothermia), 33°C (normothermia) and 37°C (hyperthermia) in temperature-controlled chambers. Hypothermia significantly reduced attentional deficits in the CRT task and spatial learning deficits in the water maze, and protected against severe brain injury in comparison with the control temperature. On the other hand, hyperthermia aggravated the behavioral deficits and brain injury. These outcomes clearly show that temperature regulation during HI insult plays an important role in the induction of behavioral and histological changes following neonatal HI insult in rats..
141. Fengling Pu, Kenichi Mishima, Nobuaki Egashira, Katsunori Iwasaki, Tomohiro Kaneko, Tomoko Uchida, Keiichi Irie, Daisuke Ishibashi, Hajime Fujii, Kenichi Kosuna, Michihiro Fujiwara, Protective Effect of Buckwheat Polyphenols Against Long-Lasting Impairment of Spatial Memory Associated with Hippocampal Neuronal Damage in Rats Subjected to Repeated Cerebral Ischemia, Journal of Pharmacological Sciences, 10.1254/jphs.94.393, 94, 4, 393-402, 2004.04, In the present experiment, we studied the action of buckwheat polyphenol (BWP, from Fagopyrum esculentum MOENCH) in a repeated cerebral ischemia model, which induced a strong and long-lasting impairment of spatial memory in 8-arm radial maze with hippocampal CA1 cell death in rats. BWP (600 mg/kg, continuous 21-day p.o.) significantly ameliorated not only the impairment of spatial memory in the 8-arm radial maze, but also necrosis and TUNEL-positive cells in the hippocampal CA1 area subjected to repeated cerebral ischemia (10 min × 2 times occlusion, 1-h interval) in rats. In order to investigate the mechanism of BWP protective action, we measured the release of glutamate and NOx- (NO2- + NO3 -) production induced by repeated cerebral ischemia in the rat dorsal hippocampus using microdialysis. A 14-day BWP treatment significantly inhibited the excess release of glutamate after the second occlusion. In addition, the BWP remarkably suppressed a delayed increase in NO x- (NO2- + NO3 -) induced by repeated cerebral ischemia in the dorsal hippocampus as determined in vivo by microdialysis. However, the 14-day treatment did not affect hippocampal blood flow in either intact rats or rats subjected to repeated ischemia measured by lasser Doppler flowmeter. These results suggested that BWP might ameliorate spatial memory impairment by inhibiting glutamate release and the delayed generation of NOx- in rats subjected to repeated cerebral ischemia..
142. Nobuaki Egashira, Kenichi Mishima, Tomoko Uchida, Nobuyoshi Hasebe, Hiroshi Nagai, Ai Mizuki, Katsunori Iwasaki, Hisanori Ishii, Ryoji Nishimura, Yukihiro Shoyama, Michihiro Fujiwara, Anandamide inhibits the DOI-induced head-twitch response in mice, Psychopharmacology, 10.1007/s00213-003-1611-y, 171, 4, 382-389, 2004.02, Rationale: Recently, Δ9-tetrahydrocannabinol (THC), the major psychoactive component of marijuana, and synthetic cannabinoid receptor agonists reportedly reduced the head-twitches induced by the 5-HT 2A/2C receptor agonist 1-(2,5-dimethoxy 4-iodophenyl)-2-amino propane (DOI) in mice, which is mediated via the activation of 5-HT 2A receptor. However, the effect of endogenous cannabinoid anandamide on the head-twitch response has not been studied. Objectives: In this study, we investigated the effect of anandamide on the DOI-induced head-twitch response in mice. Methods: Five minutes after the injection of DOI (5 mg/kg IP), the number of head-twitches was counted for a 5-min period. THC or anandamide was injected IP 60 min or 10 min before the number of head-twitches was counted, respectively. Results: THC and anandamide each reduced the DOI-induced head-twitch response. The inhibition of the DOI-induced head-twitch response by THC was reversed by SR141716A (N-piperidino-5-(4- chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazole-carboxamide), a CB 1 receptor antagonist, while the effect of anandamide was not blocked by SR141716A. Cyclooxygenase (COX) inhibitors such as aspirin and indomethacin reversed the inhibition of the DOI-induced head-twitch response by anandamide. On the other hand, COX inhibitors did not affect the inhibition of the DOI-induced head-twitch response by THC. Conclusions: Taken together, these findings suggest that the endocannabinoid anandamide may inhibit 5-HT 2A receptor-mediated function via the arachidonic acid cascade, but not via a direct interaction with the CB1 cannabinoid receptor, and that the mechanism of its action is clearly different from that of THC..
143. Nobuaki Egashira, Akito Tanoue, Fuminori Higashihara, Kenichi Mishima, Yoshihiko Fukue, Yukio Takano, Gozoh Tsujimoto, Katsunori Iwasaki, Michihiro Fujiwara, V1a receptor knockout mice exhibit impairment of spatial memory in an eight-arm radial maze, Neuroscience Letters, 10.1016/j.neulet.2003.11.050, 356, 3, 195-198, 2004.02, In this study, we examined the performance of vasopressin V1a receptor (V1aR) and vasopressin V1b receptor (V1bR) knockout (KO) mice compared to wild-type (WT) mice in an eight-arm radial maze. V1aR KO mice exhibited an impairment of spatial memory in comparison to WT mice. By contrast, we did not observe any significant differences between the V1bR KO mice and the WT mice in the eight-arm radial maze. Moreover, OPC-21268, a selective V1aR antagonist, impaired spatial memory in the eight-arm radial maze in WT mice characterized by an increased number of errors. These results suggest that the V1aR controls spatial memory in mice..
144. Katsunori Iwasaki, Eun Hee Chung, Nobuaki Egashira, Izzettin Hatip-Al-Khatib, Kenichi Mishima, Takashi Egawa, Keiichi Irie, Michihiro Fujiwara, Non-NMDA mechanism in the inhibition of cellular apoptosis and memory impairment induced by repeated ischemia in rats, Brain Research, 10.1016/j.brainres.2003.09.064, 995, 1, 131-139, 2004.01, The spatial memory impairment and expression of apoptotic cells in hippocampal CA1 cells were investigated in rats using single and repeated ischemia models. The neuroprotective and memory-improving effect of YM-90K, an α-amino-3-hydroxy-5-methyl-isoxazole-4-propionate (AMPA) receptor antagonist, was compared to MK-801, an N-methyl-D-aspartate (NMDA) receptor antagonist. Twice-repeated ischemia, but not single ischemia, impaired the spatial memory and increased expression of apoptotic cells. YM-90K, given before and 6 h after the second reperfusion, significantly improved the memory and reduced the apoptotic cells 7 days after the second reperfusion in repeated ischemia. MK-801 neither improved the spatial memory nor reduced apoptotic cells. The present study showed that delayed expression of apoptotic cells is mediated by mechanisms involving AMPA receptors, but not by NMDA receptor, during the late phase after reperfusion. YM-90K could provide neuroprotective activity and improve the spatial memory impaired by repeated ischemia..
145. Pu Fengling, Kenichi Mishima, Keiichi Irie, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Tomoaki Ikeda, Hajime Fujii, Kenichi Kosuna, Protection by buckwheat polyphenols of cell death induced by glutamate and kainate in cultured hippocampal neurons, Journal of Traditional Medicines, 10.11339/jtm.21.143, 21, 3, 143-146, 2004.01, In the present study, we examined the effect of buckwheat polyphenols (BWP) on cell death induced by glutamate and kainate in primary cultures of hippocampal neurons by assay of lactate dehydrogenase (LDH) released out of cells. BWP (100 μg/mL) could significantly prevent cell death induced by 100 μM, but not that induced by 300 μM of glutamate, whereas MK-801, a N-methyl-D-aspartate (NMDA) receptor antagonist, remarkably inhibited cell death induced by either concentration of glutamate. BWP (100 μg/ml) and 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX), an α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor antagonist, showed a protective effect on cell death induced by kainate (1 and 3 mM). These results suggest that BWP exhibits the neuroprotective action by inhibiting the AMPA receptor activity..
146. Katsunori Iwasaki, Kenichi Mishima, Nobuaki Egashira, Izzettin Hatip Al-Khatib, Daisuke Ishibashi, Keiichi Irie, Hirotoshi Kobayashi, Takashi Egawa, Michihiro Fujiwara, Effect of nilvadipine on the cerebral ischemia-induced impairment of spatial memory and hippocampal apoptosis in rats, Journal of Pharmacological Sciences, 10.1254/jphs.93.188, 93, 2, 188-196, 2003.10, We investigated the effects of nilvadipine and amlodipine on the cerebral ischemia-induced impairment of spatial memory in 8-arm radial maze performance and hippocampal CA1 apoptosis in rats. Single cerebral ischemia impaired memory without inducing apoptosis. In these rats, neither nilvadipine nor amlodipine at 3.2 mg/kg, i.p. improved the impaired memory. On the other hand, repeated cerebral ischemia (10 min ischemia × 2, 1 h interval) impaired spatial memory and induced hippocampal apoptosis 7 days after the final occlusion/reperfusion. Moreover, repeated ischemia increased the apoptotic cell number, an effect observed after 3 days and peaked after 7 days. However, mRNA expression of the apoptosis-related early oncogene bax and CPP 32 (caspase-3) was observed after 24 h. In these rats, nilvadipine, but not amlodipine, significantly improved memory, concomitantly decreased hippocampal apoptosis, and suppressed both bax and CPP 32 expression. These results suggest that nilvadipine improved the memory impairment in repeated ischemia by reducing bax and CPP 32 expression and suppressing the induction of apoptosis in the hippocampus. Nilvadipine may have a neuro-protective effect and could be a useful pharmacotherapeutic agent for cefebrovascular dementia..
147. K. Mishima, H. Tsukikawa, I. Miura, K. Inada, K. Abe, Y. Matsumoto, Nobuaki Egashira, K. Iwasaki, M. Fujiwara, Ameliorative effect of NC-1900, a new AVP4-9 analog, through vasopressin V1A receptor on scopolamine-induced impairments of spatial memory in the eight-arm radial maze, Neuropharmacology, 10.1016/S0028-3908(02)00408-2, 44, 4, 541-552, 2003.01, The mechanism by which NC-1900, a new pGlu-Asn-Cys(Cys)-Pro-Arg-Gly-NH2 (AVP4-9) analog, improves spatial memory in rats using an eight-arm radial maze was examined. Even at very low doses (0.2 ng/kg for s.c., 1 μg/kg for p.o., 1 fg for i.c.v.) NC-1900 improved scopolamine-induced impairment of spatial memory. NC-1900 (1 ng/kg, s.c.) also improved impairment of spatial memory induced by pirenzepine, a muscarinic1 (M1) receptor antagonist, and by KN-62, a Ca2+/calmodulin (CaM)-dependent protein kinase II inhibitor. [Pmp1, Tyr(Me)2]-Arg8-vasopressin, a vasopressin1A (V1A) receptor antagonist, and nicardipine, L-type Ca2+ blocker, but not OPC-31260, a V2 antagonist, suppressed the effect of NC-1900 on scopolamine-induced impairment of spatial memory. A microdialysis study showed that NC-1900 did not affect acetylcholine release in the ventral hippocampus (VH) of intact rats or of scopolamine-treated rats. NC-1900 (1 μM) increased [Ca2+]i in the VH than in the dorsal hippocampus (DH). Pretreatment with nicardipine (1 μM) and Ca2+-free conditions inhibited the NC-1900-induced [Ca2+]i response in the VH. Whereas co-administration of NC-1900 (1 μM) and carbachol (500 μM) increased [Ca2+]i in the VH. Moreover, nicardipine concentration-dependently inhibited the increase in [Ca2+]i induced by the co-administration of NC-1900 and carbachol in the VH. These results suggest that NC-1900 activates the V1A receptor at the postsynaptic cholinergic nerve, and causes a transient influx of intracellular Ca2+ through L-type Ca2+ channels, to interact with the M1 receptor. The activation of these Ca2+-dependent processes induced by NC-1900 may be involved in the positive effect of NC-1900 on scopolamine-induced impairment of spatial memory..
148. K. Mishima, F. Pu, T. Kaneko, Nobuaki Egashira, K. Iwasaki, M. Fujiwara, Post-ischemic administeration but not pre-ischemic administeration of N
G
-nitro-L-arginine prevents spatial memory impairments and apoptosis by an inhibition of a delayed increase in NO
x
-
in the hippocampus following repeated cerebral ischemia, Neuropharmacology, 10.1016/S0028-3908(02)00404-5, 44, 4, 533-540, 2003.01, In the present study, we investigated the effects of N
G
-nitro-L-arginine (L-NAME), an inhibitor of nitric oxide synthase, on repeated cerebral ischemia-induced impairment of spatial memory of the 8-arm radial maze in rats. Repeated ischemia (10 min ischemia x 2 times with 1 h interval) impaired the spatial memory in the 8-arm radial maze test and produced apoptosis in the hippocampus 7 days after final occlusion, and gradually increased the NO
x
-
levels approximately 30-180 min after the second reperfusion. Post-ischemic administration of L-NAME at a dose of 50 mg/kg, i.p. 30 min following the second occlusion, significantly attenuated the repeated ischemia-induced impairment of spatial memory in the 8-arm radial maze test and suppressed apoptosis in the hippocampus, and also significantly suppressed a delayed increase in the NO
x
-
levels induced by repeated ischemia. However, pre-ischemic administration of L-NAME at a dose of 50 mg/kg, i.p. 30 min before the first occlusion, caused about 90% mortality (the mortality rate of vehicle-treated group was 10%). These results suggest that the delayed generation of NO
x
-
may cause spatial memory impairment and induction of apoptosis in the hippocampus in rats subjected to repeated ischemia..
149. Kenichi Mishima, Takamitsu Tanaka, Fengling Pu, Nobuaki Egashira, Katsunori Iwasaki, Ryoji Hidaka, Kazuhisa Matsunaga, Jiro Takata, Yoshiharu Karube, Michihiro Fujiwara, Vitamin E isoforms α-tocotrienol and γ-tocopherol prevent cerebral infarction in mice, Neuroscience Letters, 10.1016/S0304-3940(02)01293-4, 337, 1, 56-60, 2003.01, α-tocopherol and its derivatives have been shown to be effective in reducing cerebral ischemia-induced brain damage. However, the effects of other vitamin E isoforms have not been characterized. In the present study, we investigated the effects of six different isoforms of vitamin E on the ischemic brain damage in the mice middle cerebral artery (MCA) occlusion model. All vitamin E isoforms were injected i.v., twice, immediately before and 3 h after the occlusion. α-tocopherol (2 mM), α-tocotrienol (0.2 and 2 mM) and γ-tocopherol (0.2 and 2 mM) significantly decreased the size of the cerebral infarcts 1 day after the MCA occlusion, while γ-tocotrienol, δ-tocopherol and δ-tocotrienol showed no effect on the cerebral infarcts. These results suggest that α-tocotrienol and γ-tocopherol are potent and effective agents for preventing cerebral infarction induced by MCA occlusion..
150. Nobuaki Egashira, Katsunori Iwasaki, Motoki Ishibashi, Izzetin Hatip-Al-Khatib, Benjamin Wolozin, Kenichi Mishima, Keiichi Irie, Michihiro Fujiwara, Hypoxia enhances β-amyloid-induced apoptosis in rat cultured hippocampal neurons, Japanese Journal of Pharmacology, 10.1254/jjp.90.321, 90, 4, 321-327, 2002.12, We investigated the effect of hypoxia on β-amyloid (Aβ)-induced apoptosis in rat cultured hippocampal neurons. Aβ (25 μM for 48 h) decreased the number of neuronal cells and increased the number of TUNEL-positive cells. Hypoxia (6 h) also decreased the number of neuronal cells, but did not increase the number of TUNEL-positive cells. Moreover, combined treatment with both Aβ and hypoxia (Aβ/hypoxia) significantly enhanced in decrease in the number of neuronal cells and the increase in the number of TUNEL-positive cells. Z-Asp-CH2-DCB, an inhibitor of interleukin-1β-converting enzyme (ICE), or 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-N-methyl-D-aspartate (non-NMDA) receptor antagonist, decreased the number of TUNEL-positive cells with Aβ/hypoxia. These findings suggest that ischemia or hypoxia is an important factor that facilitates the symptoms of Alzheimer's disease and that non-NMDA receptors are involved in the induction of apoptosis in patients suffering from both cerebrovascular disease and Alzheimer's disease..
151. Keiichi Irie, Kenichi Mishima, Daisuke Ishibashi, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Involvement of bcl-family expression in the spatial memory impairment induced by repeated ischemia, Life Sciences, 10.1016/S0024-3205(02)02270-1, 72, 4-5, 621-629, 2002.12, In the present study, we examined the effects of repeated ischemia (10 min × 2, 1 hr interval) on spatial memory in rats in an 8-arm radial maze test compared with single ischemia (10 min × 1). Repeated ischemia produced more severe impairment of spatial memory and stronger TUNEL-positive immunoreactivity in the hippocampal CA1 region than single ischemia at 7 days after reperfusion. Moreover, repeated ischemia altered bcl-family expression, which is related to apoptosis, while this was not affected by single ischemia. These results suggest that spatial memory impairment at 7 days after repeated ischemia may be related to apoptosis in hippocampal CA1 cells..
152. Kenichi Mishima, Nobuaki Egashira, Yoshiaki Matsumoto, Katsunori Iwasaki, Michihiro Fujiwara, Involvement of reduced acetylcholine release in Δ
9
-tetrahydrocannabinol-induced impairment of spatial memory in the 8-arm radial maze, Life Sciences, 10.1016/S0024-3205(02)02274-9, 72, 4-5, 397-407, 2002.12, To clarify the mechanism by which Δ
9
-tetrahydrocannabinol, a major psychoactive component of marijuana, impairs spatial memory in the 8-arm radial maze in rats via the cholinergic system, we used two acetylcholinesterase inhibitors, physostigmine and tetrahydroaminoacridine. Moreover, we examined the effect of Δ
9
-tetrahydrocannabinol on acetylcholine release in the frontal cortex and dorsal and ventral hippocampus using in vivo microdialysis. Physostigmine (0.01-0.05 mg/kg, i.p.) and tetrahydroaminoacridine (1-5 mg/kg, p.o.) improved the impairment of spatial memory induced by Δ
9
-tetrahydrocannabinol (6 mg/kg, i.p.) in the 8-arm radial maze. Δ
9
-tetrahydrocannabinol (6 mg/kg, i.p.) produced a significant decrease in acetylcholine release in the dorsal hippocampus as assessed by microdialysis. Moreover, tetrahydroaminoacridine at a dose of 1 mg/kg, which improved the impairment of spatial memory, reversed the decrease in acetylcholine release induced by Δ
9
-tetrahydrocannabinol in the dorsal hippocampus during 60-120 min after the Δ
9
-tetrahydrocannabinol injection. These findings suggest that inhibition of the cholinergic pathway by reduced acetylcholine release is one of the means by which Δ
9
-tetrahydrocannabinol impairs spatial memory in the 8-arm radial maze..
153. Eun hee Chung, Katsunori Iwasaki, Kenichi Mishima, Nobuaki Egashira, Michihiro Fujiwara, Repeated cerebral ischemia induced hippocampal cell death and impairments of spatial cognition in the rat, Life Sciences, 10.1016/S0024-3205(02)02269-5, 72, 4-5, 609-619, 2002.12, We developed a method of causing strong ischemic insult only in vulnerable nerve cells, such as hippocampal cells, without causing hemiplegia or difficulty in moving, by repeating cerebral ischemia for a brief time with a short interval periods. The rats subjected to 10 min of cerebral ischemia exhibited no impairment of spatial cognition at the test trial 7 days after final reperfusion. However, when the 10 min ischemia was repeated twice with a 1 hr interval, the rats exhibited a significant decrease in number of correct choices and increase in number of errors. Three times of repeated cerebral ischemia also induced a significant decrease in the number of correct choices and increase in the number of errors, but there were some rats showing motor difficulty. Cell death was typically observed in the CA1 layer of the hippocampus of rats subjected twice to 10 min of cerebral ischemia. Hippocampal and cortical acetylcholine (ACh) release weas transiently increased during the first and second 10 minutes of ischemia and normalized immediately after recirculation; thereafter, ACh release from these areas gradually decreased and showed a significantly low level at 7 days after recirculation. These results suggest that the repeated cerebral ischemia-induced impairment of spatial memory may be due to the dysfunction of hippocampal and cortical ACh systems and hippocampal cell death. The repeated cerebral ischemia model which produces cell death and ACh dysfunction in the hippocampus is thought to be useful for evaluating new drugs for the treatment of cerebrovascular dementia..
154. Kenichi Mishima, Megumi Fujii, Naoya Aoo, Tetsuya Yoshikawa, Yoshihiko Fukue, Yoko Honda, Nobuaki Egashira, Katsunori Iwasaki, Yukihiro Shoyama, Michihiro Fujiwara, The pharmacological characterization of attentional processes using a two-lever choice reaction time task in rats, Biological and Pharmaceutical Bulletin, 10.1248/bpb.25.1570, 25, 12, 1570-1576, 2002.12, Activating the noradrenergic and cholinergic systems is known to enhance attentional processes, while stimulating dopaminergic, serotonergic, and GABAergic systems suppresses them. The objective of the present study was to investigate the pharmacological characterization in the attentional processes of a two-lever choice reaction time (CRT) task using different centrally acting drugs. We designed seven parameters in this task: the correct response (CR) rate; error response rate; nonresponse (NR) rate; differential reinforcement of other behavior (DRO) responses; number of incorrect lever pressings during both the intertrial interval and DRO periods; the mean CRT of CR; and activity during 30 trials. The compounds produced different profiles at each dose. 1) Facilitative and disruptive effects on attentional processes occurred with changes in CRT alone. Scopolamine (0.1 mg/kg) and prazosin (0.3-1 mg/kg) prolonged the CRT, whereas methamphetamine (0.3 mg/kg) shortened the CRT. 2) Attentional deficits occurred with abnormal behavior showing premature response or perseverative behavior. Scopolamine (0.2-1 mg/kg), methamphetamine (3 mg/kg), Δ9-tetrahydrocannabinol (10 mg/kg), and MK-801 (0.1-0.3 mg/kg) produced a marked increase in the number of total lever pressings. 3) Motor function deficits rather than attentional deficits occurred. 8-OH DPAT (1 mg/kg) and muscimol (1 mg/kg) produced a decrease in CR and an increase in NR with a marked decrease in activity and prolonged the CRT. Activating noradrenergic α1 receptors was found to enhance the attentional processes, while blocking muscarinic receptors, α1, receptors, and NMDA receptors, and stimulating cannabinoid receptors and the dopaminergic systems impaired the attentional processes in the two-lever CRT task..
155. Nobuaki Egashira, Kenichi Mishima, Katsunori Iwasaki, Michihiro Fujiwara, Intracerebral microinjections of Δ9-tetrahydrocannabinol
Search for the impairment of spatial memory in the eight-arm radial maze in rats, Brain Research, 10.1016/S0006-8993(02)03247-X, 952, 2, 239-245, 2002.10, The purpose of this study was to identify brain sites that contribute to the Δ9-tetrahydrocannabinol (Δ9-THC)-induced impairment of spatial memory in rats. Rats were tested in the eight-arm radial maze after microinjections of Δ9-THC into one of 14 different brain regions. The bilateral microinjection of Δ9-THC (20 μg/side) impaired spatial memory when injected into the dorsal hippocampus (DH), ventral hippocampus (VH) or dorsomedial thalamus nucleus (DMT). However, rats treated with Δ9-THC into DMT produced perseverative behavior which has not been observed by systemic administration of Δ9-THC. On the other hand, spatial memory was unaffected by microinjections of Δ9-THC into the other 11 areas examined: frontal (FC) and frontoparietal (FPC) cortex, central (ACE) and basolateral (ABL) amygdaloid nucleus, medial caudate putamen (CPM), lateral hypothalamus (LH), mammillary body (MB), basal forebrain (BF), medial septal nucleus (SEP) and dorsal (DR) and median (MR) raphe nucleus. These results suggest that DH and VH may be important brain sites for the Δ9-THC-induced impairment of spatial memory..
156. Nobuaki Egashira, Kenichi Mishima, Shutaro Katsurabayashi, Tomohiro Yoshitake, Yoshiaki Matsumoto, Junichi Ishida, Masatoshi Yamaguchi, Katsunori Iwasaki, Michihiro Fujiwara, Involvement of 5-hydroxytryptamine neuronal system in Δ9-tetrahydrocannabinol-induced impairment of spatial memory, European Journal of Pharmacology, 10.1016/S0014-2999(02)01755-7, 445, 3, 221-229, 2002.06, The present study investigated the involvement of the serotonin (5-hydroxytryptamine, 5-HT) neuronal system in the Δ9-tetrahydrocannabinol-induced impairment of spatial memory in the eight-arm radial maze in rats. Δ9-Tetrahydrocannabinol (6 mg/kg, i.p.), which impairs spatial memory, significantly increased the 5-HT content in the ventral hippocampus. A microdialysis study showed that Δ9-tetrahydrocannabinol (6 mg/kg, i.p.) decreased 5-HT release in the ventral hippocampus. The 5-HT precursor, 5-hydroxy-L-tryptophan (5-HTP; 50 mg/kg, i.p.), the 5-HT re-uptake inhibitor, clomipramine (0.01 and 0.1 mg/kg, i.p.), the 5-HT receptor agonist, 5-methoxy-N, N-dimethyltryptamine (5-MeODMT; 0.01 and 0.03 mg/kg, i.p.), and the 5-HT2 receptor agonist, 1-(2,5-dimethoxy 4-iodophenyl)-2-amino propane (DOI; 10 μg/kg, i.p.), significantly attenuated the Δ9-tetrahydrocannabinol-induced impairment of spatial memory. These results suggest that the 5-HT neuronal system may be involved in the Δ9-tetrahydrocannabinol-induced impairment of spatial memory..
157. Takashi Egawa, Kenichi Mishima, Nobuaki Egashira, Misa Fukuzawa, Kohji Abe, Tetsuji Yae, Katsunori Iwasaki, Michihiro Fujiwara, Impairment of spatial memory in kaolin-induced hydrocephalic rats is associated with changes in the hippocampal cholinergic and noradrenergic contents, Behavioural Brain Research, 10.1016/S0166-4328(01)00333-3, 129, 1-2, 31-39, 2002.02, We investigated the relationship between the degree of spatial memory impairment in an 8-arm radial maze and the changes in the contents of acetylcholine (ACh) and noradrenaline (NA) in the dorsal and ventral hippocampus and the frontal cortex, along with histological changes in kaolin-induced hydrocephalic rats. Kaolin-induced hydrocephalic rats were divided into three groups (non-impaired, impaired and severely impaired) according to the degree of impairment in a radial maze. Thirty percent of the hydrocephalic rats could not solve a radial maze (severely impaired group), while the remaining hydrocephalic rats could (non-impaired rats in the standard task). Forty percent of the non-impaired rats in the standard task failed to solve the delayed-response task (impaired group), whereas the remaining rats were able to solve it (non-impaired group). A positive correlation was observed between the impairment of spatial memory and ventricular dilatation. The ACh content in the dorsal and ventral hippocampus, and the NA content in the ventral hippocampus were decreased in the severely impaired group. Moreover, the NA content in the ventral hippocampus was decreased in the impaired group. These results suggest that the impairment of spatial memory in kaolin-induced hydrocephalic rats is associated with dysfunction of the hippocampal cholinergic and noradrenergic systems..
158. Kenichi Mishima, Nobuaki Egashira, Nobue Hirosawa, Megumi Fujii, Yoshiaka Matsumoto, Katsunori Iwasaki, Michihiro Fujiwara, Characteristics of learning and memory impairment induced by Δ9-tetrahydrocannabinol in rats, Japanese Journal of Pharmacology, 10.1254/jjp.87.297, 87, 4, 297-308, 2001.12, We investigated the characteristics of Δ9-tetrahydrocannabinol (THC)-induced impairment of learning and memory using an 8-arm radial maze task, a water maze, a visual discrimination task with 2 figures and a passive avoidance test in rats. THC (6 mg/kg, i.p.) impaired spatial memory in the standard task of the 8-arm radial maze. THC (4 - 6 mg/kg, i.p.) selectively impaired working memory in a reference and working memory task of the 8-arm radial maze. Even at a dose of 10 mg/kg, THC did not impair spatial memory in the water maze. In addition, THC at a dose of 6 mg/kg, which had inhibitory effects in the 8-arm radial maze, did not affect performance in the visual discrimination task. These results indicate that at low doses (2 - 6 mg/kg), THC may not produce visual function abnormalities. THC impaired retrieval (6 mg/kg, i.p.) as well as acquisition (10 mg/kg, i.p.) in the passive avoidance test. The consolidation process was also impaired by i.c.v. injection (100 μg), but not i.p. injection (6 - 10 mg/kg) of THC. These results suggest that THC-induced impairment of spatial memory is based on the selective impairment of working memory through its effects on acquisition and retrieval processes..
159. Izzettin Hatip-Al-Khatib, Funda Bölükbasi, Kenichi Mishima, Nobuaki Egashira, Katsunori Iwasaki, Michihiro Fujiwara, Role of dopaminergic system in core part of nucleus accumbens in hyperlocomotion and rearing induced by MK-801 in rats
A behavioral and in vivo microdialysis study, Japanese Journal of Pharmacology, 10.1254/jjp.87.277, 87, 4, 277-287, 2001.12, We investigated modification of the MK-801 effect on motor activity and extracellular amines concentration by 6-hydroxydopamine (6-OHDA)-induced lesion of core nucleus accumbens (cACC) of rats. In vivo microdialysis-HPLC showed that the concentrations (fmol/μl) of dopamine (DA), dihydroxyphenylacetic acid (DOPAC) and serotonin were 0.738±0.135, 155.34±41.01 and 0.334±0.024, respectively, in the cACC of intact rats. The DOPAC/DA ratio was 264.24±94.01. Unilateral lesion of the cACC with 6-OHDA (8 μg/μl) substantially reduced DA (-93%) and DOPAC (-97%) in desipramine (30 mg/kg, i.p.)-pretreated rats (6-OHDA+DMI rats) as compared to the 65% reduction rate of both amines in saline-pretreated rats (6-OHDA+saline rats). Moreover, DOPAC was reduced by 72% in 6-OHDA+DMI rats. MK-801 increased DOPAC (426-467%) and DOPAC/DA ratio (180-230%) in intact rats. On the other hand, MK-801 increased DA by 154% and 505% in 6-OHDA+saline and 6-OHDA+DMI rats, respectively. 6-OHDA reduced the effect of MK-801 on DOPAC and DOPAC/DA ratio. In the behevioral studies, MK-801 (0.01 - 0.3 mg/kg, i.p.) increased locomotor activity and rearing of intact rats. Bilateral 6-OHDA+DMI mesion of the cACC caused greater reduction in the effect of MK-801 (0.1 mg/kg) than that of the shell nucleus accumbens. These results suggest that increased extracellular DOPAC concentration (but not DA) and DOPAC/DA ratio in the cACC plays an important role in MK-801-hyperactivity..
160. K. Mishima, K. Iwasaki, H. Tsukikawa, Y. Matsumoto, Nobuaki Egashira, K. Abe, T. Egawa, M. Fujiwara, The scopolamine-induced impairment of spatial cognition parallels the acetylcholine release in the ventral hippocampus in rats, Japanese Journal of Pharmacology, 10.1254/jjp.84.163, 84, 2, 163-173, 2000.11, We investigated the relationship between the induction of spatial cognition impairment in the 8-arm radial maze task and regional changes (ventral hippocampus (VH), dorsal hippocampus, frontal cortex, and basolateral amygdala nucleus) in brain acetylcholine (ACh) release using microdialysis in rats treated with muscarinic (M) receptor antagonists. In a behavioral study, two M1 antagonists, scopolamine (0.5 mg/kg, i.p. and 20 μg, i.c.v.) and pirenzepine (80 μg, i.c.v.) but not an M2 antagonist, AF-DX116 (40 - 80 μg, i.c.v.), disrupted spatial cognition in the 8-arm radial maze task. In brain microdialysis with Ringer's solution containing 0.1 mM eserine sulfate, scopolamine and AF-DX116, but not pirenzepine, increased ACh release in the VH. Moreover, in the bilateral injection of scopolamine (2 μg/side), the VH dorsomedial thalamus nucleus were important regions for scopolamine-induced impairment of spatial cognition. A simultaneous determination of the behavioral changes revealed that scopolamine (0.5 mg/kg, i.p.) markedly decreased the ACh contents and also increased the ACh release in all regions tested. Especially, the changes in the ACh release of the VH closely paralleled the induction of the scopolamine-induced impairment of spatial cognition. These results suggest that the blocking balance between M1 and M'2 muscarinic receptor in the VH therefore plays a major role in the spatial cognition impairment induced by scopolamine in the 8-arm radial maze task..