Chronic phencyclidine, like amphetamine, produces a decrease in [3H]spiroperidol binding in rat striatum.

Rats were treated with d-amphetamine sulfate (5 and 10 mg/kg i.p.) and phencyclidine (PCP) (5 mg/kg i.p.) twice per day. After 21 days, [3H]spiroperidol binding in striatum was reduced by all treatments; receptor number (Bmax) and not affinity (KD) was affected. These results suggest that the psychotic effect of PCP may, like those of amphetamine, involve changes in dopamine receptors.