Phencyclidine-induced disruption of an aversely motivated two-choice successive discrimination in the rat.

Rats were trained to performed an aversely motivated discriminative task in a shuttle-box. The administration of phencyclidine (PCP), 2 mg kg-1 SC at -20 min, produced disruption of discriminative performance and an increase in intertrial crosses. There were no changes in avoidance performance or in avoidance latency. Pretreatment with haloperidol, 0.1 or 0.2 mg kg-1 SC at -40 min, or remoxipride 8 mg kg-1 IP at -30 min, did not antagonize the PCP-induced disruption of discriminative performance, nor was the PCP-induced increase in number of intertrial crosses antagonized. In fact, there appeared to be a further increase in intertrial crosses, above PCP levels, by haloperidol treatment and this effect was statistically significant after remoxipride treatment. The present results, together with previous observations that also d-amphetamine disrupts discriminative conditioned avoidance behavior, suggest the possibility that this model could be used in the search for new, non-dopaminergic, antipsychotic drugs.