Body temperature was measured in a quiet procedure room maintained under identical environmental controls (temperature, humidity, and lighting) with the animal colony room. Rats (n = 5–8 per group) were habituated to the procedure room for at least 30 min before each test. Body temperature was measured by gently inserting a rectal probe (5.0 cm) and recording temperature from the digital thermometer (BAT7001H; Physitemp Instruments Inc., Clifton, NJ) (Li et al. 2009 (link); Thorn et al. 2012 (link)). During a test session, a baseline body temperature measurement was immediately followed by the injection of a dose of a drug, and the follow-up measurements were conducted every 15 or 30 min until the effect of the drug dissipated. When a drug combination was studied, the first drug was administered 10 min before the first measurement, which was immediately followed by the administration of a second drug. Rats were handled for at least 3 days before testing drugs in order to habituate rats to the procedure and were only used in one test.