Effects of centrally administered pentazocine and ethylketocyclazocine on thermoregulation in the cat.
The mechanisms for the biphasic response of unrestrained cats to centrally administered pentazocine were examined by injecting 1 mg pentazocine into the third cerebral ventricle at various ambient temperatures (TaS). The initial phase was hyperthermia at Ta = 34 degrees C, but at Ta = 22 degrees C hypothermia, which was enhanced at Ta = 0 degrees C, developed. The second phase was an increase in body temperature that occurred at all three TaS. No evidence was seen of compensatory thermoregulatory effector activity during development of either phase. The first phase can be attributed to general depression of thermoregulation whereas the second phase was likely due to an increase in the level about which body temperature was regulated. Ethylketocyclazocine (250-1000 micrograms) caused a very similar, dose-related change in temperature, neither phase of which, as reported previously for pentazocine, was reduced by a large dose of nalaxone. Thus both agonists appear to act on the same receptors to alter thermoregulation in the cat. These receptors are distinct from the naloxone-sensitive receptors stimulated by morphine.
D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects*; D002415:Cats; D004305:Dose-Response Relationship, Drug; D005260:Female; D007276:Injections, Intraventricular; D008297:Male; D010423:Pentazocine / Q000494:pharmacology*
D010423:Pentazocine