A comparison of CNS stimulants with phencyclidine on dopamine release using in vivo voltammetry

Phencyclidine (PCP) produces some neurochemical and behavioral effects in rats similar to those produced by the indirectly acting dopamine (DA) agonists amphetamine and amfonelic acid. In view of these findings, the effects of PCP, d-amphetamine and amfonelic acid on the release of DA in the rat striatum were examined by in vivo voltammetry. Drug effects on DA release were determined using newly developed electrodes selective for catecholamines. PCP (5 and 10 mg/kg IP) produced a dose-dependent decrease in the electrochemical signal that lasted for approximately 4 hr. In contrast, d-amphetamine (2.5 mg/kg, IP) and amfonelic acid (5.0 mg/kg, IP) both caused marked increases in electrochemical signals. The data provide evidence that PCP at the doses tested alters dopaminergic neurotransmission in a manner different from that of amphetamine and the non-amphetamine central nervous system stimulants by decreasing DA release from dopaminergic nerve terminals.