Thermoregulatory and locomotor activity responses of 3,4-methylenedioxymethamphetamine (MDMA) in male and female rats

MDMA; 'Ecstasy', an increasingly popular recreational drug, is known to damage brain serotonin (5-hydroxytryptamine 5-HT) neurons, cause increased locomotor activity, and produce changes in body temperature in experimental animals. Previous studies have focused on MDMA-induced behavioural and thermoregulatory changes in male rodents. The aim of this experiment was thus to examine the dose-related effects of acute administration of (±)3,4-methylenedioxymethamphetamine (MDMA; 5, 10 and 20 mg/kg i.p.) on core temperature and home-cage activity responses in both male and female rats. Acute administration of MDMA at 10 and 20 mg/kg i.p. produced a significant increase in locomotor activity in both male and female rats which lasted for approximately 200 minutes in male, and 300 minutes in female rats. The lower doses of MDMA produced a significant hypothermic response in male and female rats which lasted for approximately 30 minutes. 10 mg/kg MDMA produced a biphasic temperature response in females, an initial hypothermia followed by a hyperthermia. MDMA, at a dose of 20 mg/kg, produced an increase in rectal temperature in both female and male rats. This study indicates that female rats are more sensitive to MDMA-induced hyperactivity and changes in body temperature than males, possibly attributable to differences in metabolism of the drug, or to different receptor sensitivities.