D-1 dopamine receptor stimulation enables the inhibition of nucleus accumbens neurons by a D-2 receptor agonist

Depletion of catecholamines by pretreatment with the tyrosine hydroxylase inhibitor alpha-methyl-para-tyrosine attenuated the ability of the selective D-2 dopamine receptor agonist quinpirole to inhibit rat nucleus accumbens neurons when applied directly by microiontophoresis. Concurrent iontophoretic administration of the D-1 selective agonist SKF 38393, at currents which alone produced little inhibition, reinstated the inhibitory effect of quinpirole. These findings suggest that D-1 receptor stimulation may play a necessary 'enabling' role for D-2 receptor-mediated functional responses.