Major metabolites of (+/-)3,4-methylenedioxyamphetamine (MDA) do not mediate its toxic effects on brain serotonin neurons.

The two major metabolites of (+/-)3,4-methylenedioxyamphetamine (MDA), alpha-methyldopamine (alpha-MeDA) and 3-O-methyl-alpha-methyldopamine (3-O-Me-alpha-MeDA), were administered to rats intracerebroventricularly and into brain parenchyma. In addition, their precursors, (alpha-MeDOPA and 3-O-Me-alpha-MeDOPA, respectively) were administered systemically, individually and in combination. None of these treatments produced a lasting depletion of brain serotonin (5-HT). These findings suggest that neither of MDA's major metabolites mediate its toxic effects on 5-HT neurons and that either a minor metabolite is responsible or that alternate mechanisms are involved.