Effects of phencyclidine on spontaneous and excitatory amino acid-induced activity of ventral tegmental dopamine neurons: an extracellular in vitro study.

Extracellular single-unit recordings in rat midbrain slices were used to assess the effects of phencyclidine (PCP) on the spontaneous and excitatory amino acid-induced firing of ventral tegmental (VTA) dopamine neurons. Perfusion with PCP concentrations from 10 nM to 100 microM resulted in only minimal decreases in firing rate. Neither excitatory effects 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-hydroxy-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 in the whole animal preparation.