Dopamine enhances Met-enkephalin efflux from rat striatal slices.

The basal release of Met-enkephalin immunoreactive material (ME-IR) from rat striatal slices is doubled by the in vitro addition of 5 X 10(-5) M dopamine. The K+ evoked release of ME-IR is also slightly enhanced by exposing the slices to dopamine. The effect of dopamine is shared by apomorphine but not by norepinephrine. Neuroleptics do not alter the basal or the K+-stimulated ME-IR release but reverse the dopamine-induced increase. These results suggest that the stimulation of dopamine receptors may influence the enkephalin release within striatum.