State-dependent effects of beta-endorphin on core temperature in stressed and non-stressed rats.
beta-Endorphin, gamma-endorphin, delta-endorphin and morphine injected i.c.v. caused hyperthermia in non-stressed rats; however, the same dose of beta-endorphin and morphine caused hypothermia in stressed animals. These effects of beta-endorphin were antagonized by naloxone. The results suggest that effects of beta-endorphin are different depending on the animal's state and that these effects are mediated via opioid receptors.
D000818:Animals; D001831:Body Temperature / Q000187:drug effects*; D004723:Endorphins / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013315:Stress, Psychological / Q000503:physiopathology*; D001615:beta-Endorphin
D004723:Endorphins; D009270:Naloxone; D001615:beta-Endorphin; D009020:Morphine