Body Temperature Response to Cocaine and Diazepam in Morphine-Treated Rats

Since cocaine or diazepam are used clinically and/or abused concomitantly with narcotics, this study was designed to determine if morphine-dependent, morphine-withdrawn, or acute morphine rats exhibit an altered core body temperature at 24 or 4 °C to either cocaine (10, 20, or 30 mg/kg i.p.) or diazepam (2 or 4 mg/kg i.p.). At 24 °C, each dose of cocaine manifested hyperthermia in all groups of rats except morphine-dependent whereas at 4 °C cocaine produced hypothermia in all groups except morphine-dependent. At both 24 and 4°C, diazepam, 2 or 4 mg/kg, caused a hypothermic response in control, dependent, and withdrawn animals. At 24 °C, administration of acute morphine alone induced a hyperthermia which was antagonized by both doses of diazepam. At 4°C, acute morphine alone induced an initial hypothermia followed by a hyperthermia; both doses of diazepam potentiated the hypothermic response to acute morphine. Thus, significant alterations in core body temperature may be induced following the administration of cocaine or diazepam to morphine-treated rats.