Systemic administration of the putative selective D3 receptor agonist 7-hydroxy-2-(N,N-di-n-propylamino)tetralin (7-OH-DPAT) consistently decreased extracellular dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the nucleus accumbens and dopaminergic neuronal activity in the ventral tegmental area. 7-OH-DPAT inhibited dopamine release in the nucleus accumbens also when locally perfused through the dialysis probe. The results suggest the possibility that stimulation of dopamine D3 receptors with 7-OH-DPAT mimic biochemical and electrophysiological actions previously ascribed to D2 autoreceptor stimulation; however the lack of selective D3 antagonist precludes any firm conclusion in this sense.