A parametric study of the behavioral effects of phencyclidine in adult cats

Five adult cats received four doses of phencyclidine to determine the behavioral effects of this compound. On alternate weeks the animals received control injections of saline vehicle. Dose-dependent behavioral changes occurred in three general categories (posture, locomotor activity and stereotyped head movements). In small doses (0.1 and 0.5 mg/kg), major postural effects consisted of head and body tremors and loss of hindlimb support. In larger doses (1.0 and 2.0 mg/kg), the postural effects occurred more rapidly and became more severe as animals lost both forelimb and hindlimb support and ultimately became immobile. Small doses of phencyclidine produced decreases in locomotor activity, followed by increases. Larger doses produced initial increases in activity. Increases in head movement stereotypies were produced by all doses of phencyclidine.