Potentiation of phencyclidine-induced dopamine release in the rat striatum by the blockade of dopamine D₂ receptor

Local perfusion with phencyclidine (PCP) increased extracellular dopamine levels in the rat striatum in a dose-dependent manner, as measured by in vivo microdialysis. While pretreatment with SCH 23390, a selective dopamine D₁ receptor antagonist, had no significant effect on PCP-induced increases in extracellular dopamine levels, pretreatment with YM-09151-2 (cis-N-(1-benzyl-2-methylpyrrolidin-3-yl)-5-chloro-2-methoxy-4-methylaminobenzamide), a selective dopamine D₂ receptor antagonist, markedly potentiated the effect of PCP. These results suggest that the blockade of dopamine D₂ presynaptic autoreceptors strongly potentiates the PCP-induced dopamine release in the striatum.