The effects of haloperidol and clozapine on PCP- and amphetamine-induced suppression of social behavior in the rat.

Previous work has shown that phencyclidine (PCP) and amphetamine decrease social behavior in rats. The purpose of the present study was to determine the effects of the dopamine antagonists clozapine and haloperidol on PCP- and amphetamine-induced changes in rat social behavior. An intruder paradigm was used, in which rats were injected with drug and placed into a stable home colony of three other rats. Social behaviors were recorded for 30 min. Both amphetamine (4.0 mg/kg) and PCP (4.0 mg/kg) substantially reduced social behavior. Haloperidol and clozapine did not produce a general reversal of the effects of amphetamine or PCP on the total number of social behaviors. Nevertheless, 0.025 mg/kg haloperidol did reverse the effects of PCP and amphetamine on some of the specific social behaviors observed (side threats, mounting, crawling under). Clozapine had no effect on reversing the actions of amphetamine on social behavior, but 2.0 mg/kg clozapine did reverse the effect of PCP on side threats and mounting. These results indicate that DA antagonists do not restore normal social behavior in animals treated with PCP or amphetamine, but can reverse some of the effects of PCP or amphetamine on specific social behaviors.