Stimulant effects of 3,4-methylenedioxymethamphetamine in the nucleus accumbens of rat.

This study examined the behavioral effects in rats of intracerebral administration of S(+)-3,4-methylenedioxymethamphetamine (S-MDMA) using an automated holeboard and open-field apparatus. Administration of S-MDMA into the nucleus accumbens septi produced locomotor hyperactivity. Although the stimulant effects of S-MDMA administered systemically are antagonized by fluoxetine pretreatment, the activating effects of S-MDMA administered into the nucleus accumbens were not antagonized by fluoxetine. A similar increase in locomotor activity was observed after S-amphetamine administration into the nucleus accumbens. In contrast, the selective 5-HT-releasing drug and S-MDMA congener N-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine (MBDB) produces MDMA-like locomotor hyperactivity when administered systemically but did not alter locomotor activity when injected into the nucleus accumbens. These data indicate that S-MDMA actions in the nucleus accumbens are pharmacologically distinct from the primary effects of systemically administered S-MDMA. Behavioral effects of S-MDMA in the nucleus accumbens may result from the catecholamine-releasing properties that S-MDMA shares with S-amphetamine and not via the 5-HT-releasing properties that it shares with MBDB.