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

Injecting S-MDMA (a form of MDMA, or ecstasy) directly into a brain region called the nucleus accumbens made rats more active, similar to the effect of amphetamine. Blocking serotonin with fluoxetine did not prevent this hyperactivity, even though it blocks the effects of systemically given S-MDMA. A drug that only releases serotonin, MBDB, did not increase activity when injected into the nucleus accumbens, though it does when given systemically. These results suggest that S-MDMA's effects in the nucleus accumbens are due to its ability to release catecholamines like dopamine, not serotonin, and differ from its systemic actions.

Study at a glance

Abstract

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.