Phencyclidine-induced release of [3H]dopamine from chopped striatal tissue.

Phencyclidine was examined for its ability to release [3H]dopamine ([3H]DA) from prelabelled chopped rat striatal tissue. A dynamic perfusion system was used in order to minimize the effects of drugs on uptake mechanisms. Cocaine and S-(+)-amphetamine were used to distinguish uptake inhibition from a neurotransmitter releasing action. Phencyclidine, starting at 3 microM caused a dose-dependent increase in efflux of [3H]DA from chopped striatal tissue. In this same preparation, cocaine, a known neuronal uptake inhibitor of dopamine, was unable to release [3H]DA except in the largest dose of 100 microM. S-(+)Amphetamine, a known releaser of neuronal dopamine, was found to be about ten times more potent then phencyclidine in causing a dose-dependent release of [3H]DA. The results of the above experiments are discussed in relation to the ability of phencyclidine to decrease the synaptosomal accumulation of [3H]DA. It is concluded that some of the psychoactive effects of phencyclidine may be due to the ability of phencyclidine to elicit a release of dopamine from dopaminergic neurons.