Critical Role of Peripheral Vasoconstriction in Fatal Brain Hyperthermia Induced by MDMA (Ecstasy) under Conditions That Mimic Human Drug Use

MDMA (Ecstasy) can cause fatal brain hyperthermia when taken in hot, crowded environments, even at moderate doses that are harmless under cool, quiet conditions. In male rats, MDMA at 9 mg/kg (about one-fifth of the lethal dose) produced only weak brain temperature increases under standard lab conditions (quiet rest, 22–23°C). However, social interaction with another male rat and a warm environment (29°C) dramatically amplified brain hyperthermia. The key mechanism is peripheral vasoconstriction, which prevents heat dissipation through the skin. This shows that doses of MDMA that are nontoxic in cool, quiet settings become highly dangerous under conditions mimicking recreational use at rave parties or other hot, crowded venues.

Study at a glance

Abstract

MDMA (Ecstasy) is an illicit drug used by young adults at hot, crowed "rave" parties, yet the data on potential health hazards of its abuse remain controversial. Here, we examined the effect of MDMA on temperature homeostasis in male rats under standard laboratory conditions and under conditions that simulate drug use in humans. We chronically implanted thermocouple microsensors in the nucleus accumbens (a brain reward area), temporal muscle, and facial skin to measure temperature continuously from freely moving rats. While focusing on brain hyperthermia, temperature monitoring from the two peripheral locations allowed us to evaluate the physiological mechanisms (i.e., intracerebral heat production and heat loss via skin surfaces) that underlie MDMA-induced brain temperature responses. Our data confirm previous reports on high individual variability and relatively weak brain hyperthermic effects of MDMA under standard control conditions (quiet rest, 22-23°C), but demonstrate dramatic enhancements of drug-induced brain hyperthermia during social interaction (exposure to male conspecific) and in warm environments (29°C). Importantly, we identified peripheral vasoconstriction as a critical mechanism underlying the activity- and state-dependent potentiation of MDMA-induced brain hyperthermia. Through this mechanism, which prevents proper heat dissipation to the external environment, MDMA at a moderate nontoxic dose (9 mg/kg or ~1/5 of LD50 in rats) can cause fatal hyperthermia under environmental conditions commonly encountered by humans. Our results demonstrate that doses of MDMA that are nontoxic under cool, quiet conditions can become highly dangerous under conditions that mimic recreational use of MDMA at rave parties or other hot, crowded venues.