PT - JOURNAL ARTICLE AU - M Johnson AU - A A Letter AU - K Merchant AU - G R Hanson AU - J W Gibb TI - Effects of 3,4-methylenedioxyamphetamine and 3,4-methylenedioxymethamphetamine isomers on central serotonergic, dopaminergic and nigral neurotensin systems of the rat. DP - 1988 Mar 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 977--982 VI - 244 IP - 3 4099 - http://jpet.aspetjournals.org/content/244/3/977.short 4100 - http://jpet.aspetjournals.org/content/244/3/977.full SO - J Pharmacol Exp Ther1988 Mar 01; 244 AB - This study demonstrates that the isomers of 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA) are different in their ability to induce changes in serotonergic parameters and nigral concentrations of neurotensin-like immunoreactivity. With five successive doses (3.5 mg/kg) the d-MDA isomer was more potent than the l-MDA in its ability to decrease the concentrations of serotonin in the frontal cortex and hippocampus. The same difference occurred in the ability to decrease the hippocampal activity of tryptophan hydroxylase as well as the hippocampal and neostriatal 5-hydroxyindoleacetic acid concentrations. However, both isomers of MDMA were equipotent in their ability to decrease serotonergic parameters in the brain areas examined. When the doses were increased to 5 and 10 mg/kg, both isomers of MDA were equipotent in their effects on the serotonin system, whereas the l-MDMA was significantly less potent than its d isomeric counterpart in causing a decrease in serotonergic parameters of the different brain areas. In contrast, treatments with any of the isomers appeared to have a minimal impact on neostriatal dopaminergic parameters. However, treatment with MDA or MDMA caused increases in the nigral concentrations of neurotensin, with the d isomer of both compounds having substantially greater effects on this neuropeptide system. These increases are suspected to result from drug-released dopamine. This study demonstrates that at selected doses, the d isomers of MDA and MDMA are more potent than their l forms in affecting neurochemical systems, whereas high doses of either isomer of MDA share a common ability to induce changes in the serotonergic system that are likely associated with neuronal damage.