Atypical properties of several classes of antipsychotic drugs on the basis of differential induction of Fos-like immunoreactivity in the rat brain

• Published in: Life sciences (1973) Vol. 76; no. 2; pp. 225 - 237
• Main Authors: Oka, Takuro, Hamamura, Takashi, Lee, Youmei, Miyata, Shinji, Habara, Toshiaki, Endo, Shiro, Taoka, Hideki, Kuroda, Shigetoshi
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 26-11-2004
• Subjects: Animals; Antipsychotic Agents - administration & dosage; Antipsychotic Agents - pharmacology; Antipsychotic drugs; Atypicality; Brain - drug effects; Brain - metabolism; c-fos; Cell Nucleus - drug effects; Cell Nucleus - metabolism; Corpus Striatum - drug effects; Corpus Striatum - metabolism; Immediate early gene; Immunohistochemistry; Injections, Subcutaneous; Male; Neurons - drug effects; Neurons - metabolism; Nucleus Accumbens - drug effects; Nucleus Accumbens - metabolism; Proto-Oncogene Proteins c-fos - biosynthesis; Rats; Rats, Wistar; Immunohistochemistry; c-fos; Antipsychotic drugs; Atypicality; Immediate early gene
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/j.lfs.2004.08.009

Acute administration of typical and atypical antipsychotics has been reported to induce regionally distinct patterns of c-Fos expression in the rat forebrain. Furthermore, atypical index, the difference in the extent of increased Fos-like immunoreactivity (Fos-LI) in the nucleus accumbens (NAc) shell versus the dorsolateral striatum (DLSt), has been proposed to classify antipsychotics into typical or atypical antipsychotics. The present study was conducted to investigate the atypical properties of 24 antipsychotics that are used in Japan and blonanserin, a novel 5-HT
2A and D
2 receptor antagonist. We systematically examined the effects of the drugs on Fos-LI in the NAc and DLSt in the rat brain using immunohistochemistry and calculated the atypical index, comparing with those of haloperidol and clozapine. Floropipamide, oxypertine, nemonapride, pimozide and mosapramine, as well as clozapine, olanzapine, quetiapine and risperidone, showed high positive atypical index. Zotepine, perospirone, sulpiride, moperone, sultopride, thioridazine, carpipramine, clocapramine and blonanserin showed moderate ones. In contrast, fluphenazine, bromperidol, timiperone, spiperone, propericiazine, perphenazine, chlorpromazine and levomepromazine had negative atypical index like haloperidol. These results suggest that not only so-called atypical antipsychotics, but also several conventional drugs, possess atypical properties.