The effects of repeated administration of MDMA on the expression of sexual behavior in the male rat.

3,4-Methylenedioxymethamphetamine (MDMA, "Ecstasy") is a potent neurotoxin which preferentially produces 5-HT nerve terminal degeneration in the CNS in both rodents and primates. Timely research on the behavioral effects of acute and long term treatment of MDMA is critical due to the neuropathological effects of MDMA and its abuse liability. Presently, there are no published reports that have systematically examined the effects of acute or chronic treatment of MDMA on animal sexual behavior. Accordingly, the effects of repeated systemic administration of MDMA on a variety of parameters of male sexual behavior in sexually vigorous male rats were studied. Treatment consisted of subcutaneous injections of MDMA (40 mg/kg) or saline (1 ml/kg) every 12 hours for 4 consecutive days. In addition, neurochemical assessments of brain 5-HT and 5-HIAA depletion following repeated MDMA treatment were also conducted using reverse phase liquid chromatography. The results of this study revealed that repeated systemic administration of MDMA to sexually vigorous male rats produced a transient disruption of the expression of male copulatory behavior. In addition, in MDMA-treated males that did display copulatory behavior, both the ejaculation latency and postejaculatory interval were dramatically lengthened when compared to saline injected controls. Surprisingly, one week after the first behavioral test, copulatory behavior in MDMA treated rats appeared unaffected despite a marked depletion of 5-HT and 5-HIAA content in the striatum, and hippocampus.