Clozapine but not haloperidol suppresses the changes in the levels of neuropeptides in MK-801-treated rat brain regions.
Noncompetitive NMDA receptor antagonist (+)MK-801 is known to induce neurotoxicity and schizophrenia-like symptomatology where atypical neuroleptic clozapine is effective in contrast to typical neuroleptic, haloperidol. Although neuropeptides are implicated in memory and cognition, their roles in schizophrenia are not well understood. In the present study, we therefore examined the possible roles of neuropeptides, cholecystokinin (CCK) and somatostatin (SS) in the posterior cingulate/retrosplenial cortices (PC/RSC), frontal cortex, and hippocampus of a MK-801-induced schizophrenia-like model rat brain. This study further investigated the pretreated effect of atypical versus typical neuroleptics on the peptidergic system. SS mRNA and peptide levels significantly decreased in the PC/RSC and hippocampus but not in the frontal cortex 3 days after 0.5 mg/kg MK-801 treatment whereas CCK mRNA and peptide levels significantly decreased in all of the brain regions examined. Pretreatment with clozapine but not haloperidol completely recovered the changes in both mRNA and peptide levels of SS and CCK in those brain regions. These data suggest that peptidergic system in the brain presumably plays an important role in the control of negative schizophrenia.
Laboratory of Natural Information Science, Graduate School of Integrated Science, Yokohama City University, 22-2 Seto, Yokohama 236-0027, Japan.
Mohammad
M
Arif
Md Mahiuddin
MM
Ahmed
Yukiko
Y
Kumabe
Hajime
H
Hoshino
Toshiyuki
T
Chikuma
Takeshi
T
Kato
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism*; D003024:Clozapine / Q000494:pharmacology*; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006220:Haloperidol / Q000494:pharmacology*; D008297:Male; D009479:Neuropeptides / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012737:Sex Factors
D009479:Neuropeptides; D016291:Dizocilpine Maleate; D003024:Clozapine; D006220:Haloperidol