Repeated MDMA (“Ecstasy”) exposure in adolescent male rats alters temperature regulation, spontaneous motor activity, attention, and serotonin transporter binding

Repeated exposure to a moderate dose of MDMA during adolescence in male rats caused acute effects such as hypothermia, serotonin syndrome behavior, and ejaculation, and slowed body weight gain. Later, after the drug was stopped, the animals showed altered habituation to an open field, increased activity in an elevated plus maze, reduced attention in a novel object recognition test, and decreased serotonin transporter binding in the neocortex. These results indicate that even a moderate MDMA regimen during adolescence can produce lasting behavioral and neurochemical changes.

Study at a glance

Abstract

Previous research in our laboratory found that repeated exposure of adolescent rats to 3,4-methylenedioxymethamphetamine (MDMA) impaired working memory and reduced anxiety. The present experiment extended these findings by investigating the physiological, behavioral, and neurotoxic effects of a modified MDMA treatment regimen. Male Sprague-Dawley rats received 5 mg/kg of MDMA hourly for a period of 4 hr on every fifth day from postnatal day 35-60. Acute effects of the MDMA treatment included hypothermia, serotonin syndrome behavior, and ejaculation. Body weight gain was attenuated by repeated drug administration. The animals completed anxiety and working memory tests beginning 4 days after the final MDMA dose. MDMA altered habituation to the open-field, increased locomotor activity in the elevated plus-maze, decreased attention in the novel object-recognition test, and reduced serotonin transporter binding in the neocortex. These results indicate that repeated exposure to a relatively moderate MDMA dose during adolescence produces later changes in behavior and neurochemistry.