High ambient temperature facilitates the acquisition of 3,4-methylenedioxymethamphetamine (MDMA) self-administration
bioRxiv (Cold Spring Harbor Laboratory) Shawn. M. Aarde, Pai-Kai Huang, Michael A. Taffe 1 citation preprint
In rats, high ambient temperature (30°C) increases the acquisition of intravenous self-administration of MDMA more than low temperature (20°C). Initially, MDMA caused similar hypothermia in both temperature groups, but this effect diminished over training in the hot group. Activity levels, initially lower in the hot group, became similar by the end of training. When temperature conditions were swapped, rats trained in the hot condition increased MDMA intake under cold, while those trained in the cold modestly decreased intake under hot. Rats with higher MDMA intake showed blunted hypothermia after non-contingent MDMA. High temperature alone raised brain reward thresholds, and MDMA lowered thresholds below baseline only at low temperature. The findings suggest that high temperature enhances MDMA self-administration acquisition through an aversive effect rather than thermoregulatory motivation.