Treatment of rats with serotonin (5-HT) precursors tryptophan (TRP, 400 mg/kg) and 5-hydroxytryptophan (5-HTP, 50 mg/kg) was shown to attenuate MDMA (20 mg/kg) induced serotonergic neurotoxicity as measured by [3H]-paroxetine binding in the striatum, hippocampus, and frontal cortex of the rat brain. Hippocampal 5-HT and 5-HIAA levels were also indicative of the protective effects of TRP and 5-HTP. These results suggest that depletion of 5-HT stores is important for MDMA-induced neurotoxicity. The possible significance of this 5-HT depletion in MDMA-induced serotonergic terminal degeneration is also discussed.
