EFFECTS OF PHENCYCLIDINE ON SPONTANEOUS AND EXCITATORY AMINO ACID-INDUCED ACTIVITY OF VENTRAL TEGMENTAL DOPAMINE NEURONS - AN EXTRACELLULARINVITRO STUDY

Extracellular single-unit recordings in rat midbrain slices were used to assess the effects of phencyclidine (PCP) on the spontaneous and ex citatory amino acid-induced firing of ventral tegmental (VTA) dopamine neurons. Perfusion with PCP concentrations from 10 nM to 100 muM resu lted in only minimal decreases in firing rate. Neither excitatory effe cts nor changes in firing pattern were ever observed upon exposure to PCP. In contrast, PCP selectively antagonized the stimulatory effects of N-methyl-D-aspartate (NMDA), but did not alter alpha-amino-3-hydrox y-5-methyl-4-isoxazole proprionic acid (AMPA)- or kainate (KA)-induced excitations. These results are discussed in relation to the low-dose stimulatory effects of PCP on ventral tegmental A10 dopamine neurons i n the whole animal preparation.