In rats, MDMA (ecstasy) causes hyperthermia at normal or warm room temperatures but hypothermia in cool conditions. At 15°C, MDMA rapidly lowered rectal temperature; this effect was blocked by a dopamine D2 receptor antagonist but not a D1 antagonist. A neurotoxic MDMA regimen reduced serotonin in the brain by about 30% after a week. This serotonin lesion did not affect tail temperature increases when rats moved from 20°C to 30°C, but led to lower tail temperatures when returned to 24°C. Acute MDMA in lesioned rats at 30°C caused a sustained drop in tail temperature. The findings suggest that thermoregulatory problems in MDMA-lesioned rats stem partly from impaired heat loss through the tail, a key heat-loss organ.
Repeated doses of MDMA (ecstasy) given to rats in a single session cause a dose-dependent increase in body temperature and long-term damage to serotonin neurons in the brain, but not to dopamine neurons. A dosing schedule of three injections of 4 mg/kg led to about a 50% loss of serotonin in the hippocampus, cortex, and striatum, while three injections of 6 mg/kg led to about a 65% loss. When rats were housed in a hot environment (30 °C), the same dose produced a larger temperature increase (up to 2.6 °C) and a 65% loss of serotonin in the cortex and hippocampus, with no loss of dopamine in the striatum.