Electrophysiological effects of phencyclidine in the medial prefrontal cortex of the rat

The effects of local applications of phencyclidine (PCP) and dopamine (DA) on neurons of the medial prefrontal cortex were investigated using single unit recording techniques. The activity of the majority of cells in the deeper layers of the medial prefrontal cortex was depressed by both phencyclidine and DA, whereas increases, as well as decreases, in the firing rates were observed in cells located in the superficial cortical layers. The stereospecificity of the responses of deeper cells to phencyclidine was demonstrated using the enantiomers of 1-(-1-phenylcyclohexyl)-3-methylpiperidine (PCMP). Phencyclidine was found to be 1.5 times more potent than (+) PCMP and 3 times more potent than (-) PCMP. Finally, the DA receptor antagonist fluphenazine, blocked the phencyclidine-elicited depressions of unit activity in the deep prefrontal cortex. Taken together, the data indicate that the DA-like effects of phencyclidine on neurons of the medial prefrontal cortex are mediated by DA receptors and provide pharmacological support for the idea that psychomotor stimulant drugs have specific actions on targets of the ventral tegmental area (A10) dopamine system.