Oxidative metabolite of dopamine, 3,4-dihydroxyphenylacetaldehyde, induces dopamine release from PC12 cells by a Ca2+-independent mechanism.

3,4-dihydroxyphenylacetaldehyde (DOPALD), an oxidative metabolite of dopamine (DA), induced dose-dependent DA release from pheochromocytoma (PC12) cells without affecting leakage of lactate dehydrogenase from the cells. DOPALD-induced DA release was independent of extracellular Ca2+ concentration and was not blocked by nifedipine, an L-type Ca2+ channel antagonist. These results indicated a novel intrinsic role of DOPALD in dopaminergic nerve terminals that may take part in the activation of dopamine neurons.