EFFECTS OF 4 ANTIPSYCHOTICS ON PUNISHED RESPONDING IN RATS

In Experiment 1, the benzodiazepine chlordiazepoxide (CDP), two typica l antipsychotics, haloperidol (HAL) and chlorpromazine (CPZ), and the atypical antipsychotic clozapine (CLZ) were evaluated for antipunishme nt effects in rats in a modified Geller-Seifter conflict procedure [MU LT fixed interval (FI) 60-s, fixed ratio (FR) 1 (food + shock)]. In Ex periment 2, CDP and thioridazine (THD) were similarly tested. CLZ (2.5 and 5.0 mg/kg), but not HAL, CPZ, or THD, selectively increased punis hed responding, although the magnitude of effect was smaller than that observed for CDP. Possible serotonergic mechanisms for CLZ's action i n this model and the possible importance of serotonergic activity for the development of other atypical antipsychotic drugs are discussed.