High ambient temperature facilitates the acquisition of 3,4-methylenedioxymethamphetamine (MDMA) self-administration.

Rationale: MDMA alters body temperature in rats with a direction that depends on the ambient temperature (T). The thermoregulatory effects of MDMA and T may affect intravenous self-administration (IVSA) of MDMA but limited prior reports conflict.

Objective: To determine how body temperature responses under high and low T influence MDMA IVSA.

Contrasting effects of d-methamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxypyrovalerone, and 4-methylmethcathinone on wheel activity in rats.

Background: Reports from U.S., U.