Summary: We have investigated the ability of the 5HT2‐receptor antagonist ketanserin to affect the hyperthermia produced by methylenedioxymethamphetamine (MDMA) in conscious mice and examined whether α1‐adrenoceptor antagonist actions are involved. Mice were implanted with intra‐abdominal temperature probes under anaesthesia and allowed 2 weeks recovery. MDMA (20 mg kg−1) was administered...