Selective memory impairment by phencyclidine in rats.

Phencyclidine (PCP) users sometimes report lack of recall of events occurring while they are under the influence of the drug. The present experiment was designed to test whether rats remember information learned after PCP administration. Rats were trained to choose one arm of a T-maze to obtain a food reward. The following day they were injected with either PCP (1 mg/kg) or vehicle and trained to choose the opposite arm for a reward (reversal learning). A third group of rats received neither injections nor training on the second day. On the third day, all rats were tested for their preference of maze arms. Rats who had been injected with saline before reversal learning chose the arm rewarded during the reversal, while rats receiving PCP on the second day chose randomly. The rats which did not learn the reversal chose the arm learned on day 1. These results indicate that while PCP did not interfere with the rats ability to learn, it interfered with long-term storage of information.