Effects of administration of dopamine D2 agonist quinpirole on exploratory locomotion

Injections of the dopamine D2 agonist quinpirole (LY 171555) into the nucleus accumbens reduced exploratory locomotion in a dose-dependent manner. Injections of the dopamine D1 agonist SKF 38393 had no effect on exploratory locomotion. The results are consistent with observations from recent electrophysiological and behavioral experiments which suggest a presynaptic action of the D2 agonist. It is proposed that quinpirole activates D2 receptors on the axon terminals of glutamatergic hippocampal-accumbens neurons that are associated with exploratory locomotion.