Effects of dopaminergic drugs on phencyclidine-induced behavior in the rat

Phencyclidine-induced behavior was studied in combination with drugs which block or enhance central dopamine activity. Haloperidol inhibited phencyclidine-induced stereotyped behavior and locomotor activity, and increased ataxia at all dose levels used (2.0, 4.0 and 6.0 mg/kg). Apomorphine potentiated phencyclidine-induced stereotypy at all doses in later post-injection periods (beyond 30 min). The effects of apomorphine on phencyclidine-induced locomotor activity were dose-dependent, showing inhibition at 2.0 mg/kg and enhancement at 4.0 and 6.0 mg/kg. These findings support suggested involvement of dopamine in phencyclidine-induced behavior and indicate the value of concurrent assessment of different phencyclidine-induced behavior for evaluating neurotransmitter effects.