British Journal of Pharmacology
February 20, 2006
Sotiria Bexis, James R. Docherty
62 citations
In conscious rats, the amphetamine derivatives MDMA, MDA, and MDEA (each at 20 mg/kg) affected blood pressure, heart rate, body temperature, and movement. MDA caused the largest and most prolonged rise in blood pressure, accompanied by a slowed heart rate, while MDEA produced a brief, non-significant drop in diastolic pressure. All three initially lowered core body temperature, but MDA later caused a rise in temperature, with recovery speed fastest for MDA, then MDMA, then MDEA. Blocking α2A-adrenoceptors with BRL 44408 prolonged MDMA's hypothermic effect and triggered increased movement only with MDMA. In isolated rat aorta and vas deferens, the drugs' potency for contraction matched MDA > MDMA > MDEA, with MDEA acting as an antagonist.
British Journal of Pharmacology
July 18, 2005
Sotiria Bexis, James R. Docherty
43 citations
MDMA produces complex effects on body temperature, including both hypothermia and hyperthermia, depending on ambient temperature and species. This study in mice found that MDMA acts as an α₂-adrenoceptor agonist. The α₂-adrenoceptor agonist clonidine caused hypothermia in wild-type mice but not in mice lacking the α₂A-adrenoceptor. MDMA alone caused significant hyperthermia in wild-type mice, but a biphasic response (hypothermia followed by hyperthermia) in knockout mice. Blocking the α₂A-adrenoceptor in wild-type mice before MDMA resulted in initial hypothermia. Thus, MDMA's α₂A-adrenoceptor agonist actions surprisingly shift the body temperature response from biphasic to monophasic hyperthermia.
British Journal of Pharmacology
April 30, 2009
Sotiria Bexis, James R. Docherty
36 citations
In conscious mice, the drug MDMA (20 mg/kg) caused a slow rise in body temperature peaking at 1.8°C above baseline about 130 minutes after injection. A low dose of the β3-adrenoceptor antagonist SR59230A (0.5 mg/kg) slightly reduced this hyperthermia. A high dose of SR59230A (5 mg/kg) instead triggered an early drop in temperature, an effect also produced by the α1-adrenoceptor blocker prazosin. Further tests showed that SR59230A also blocks α1-adrenoceptors. Thus, SR59230A alters MDMA's temperature effects mainly by blocking α1-adrenoceptors, which unmasks a hypothermic response, and to a lesser extent by possibly blocking β3-adrenoceptors to slightly reduce later hyperthermia.