NALOXONE RESISTANT CHANGES IN BODY-TEMPERATURE OF THE CAT INDUCED BY INTRACEREBROVENTRICULAR INJECTION OF PENTAZOCINE

1. 1. Injection of pentazocine (125-1000 μg) into the third cerebral ventricle of unrestrained, conscious cats induced an initial hypothermia which lasted 3-4 hr and was followed by a prolonged hyperthermia. Both responses were dose-related. 2. 2. Neither response to pentazocine was inhibited by doses of naloxone hydrochloride up to 1 mg centrally or 5 mg/kg i.v. 3. 3. Hyperthermic responses to morphine were inhibited by doses of nalox one hydrochloride as low as 5 μg centrally or 25 μg/kg i.v. 4. 4. These results indicate that pentazocine alters body temperature in the cat by acting on different receptors than those activated by morphine to cause hyperthermia. © 1979.