The effects of opiate receptor agonists and antagonists on the stress-induced secretion of corticosterone in mice.
1 Intraperitoneal administration of normorphine, morphine or naloxone or exposure to ether vapour for 1 min, elevated plasma corticosteroid concentrations in mice. 2 Injection of saline or exposure to ether vapour rendered mice less sensitive to a subsequent exposure to ether vapour 15 min later. 3 Treatment with normorphine (50 mg/kg) potentiated the corticosteroid response to ether stress whilst pentazocine (20 mg/kg), naltrexone (10 mg/kg), morphine (24 mg/kg), levorphanol (20 mg/kg) and naloxone (50 mg/kg) prevented the stress-induced elevation of plasma corticosteroids. 4 Both naloxone and morphine inhibited the potentiation by normorphine of the response to ether, the dose of naloxone required being higher than that for inhibition of normorphine analgesia. 5 It is concluded that endogenous opioid peptides may be involved in the control of the response to ether stress in mice.
D000698:Analgesia; D000818:Animals; D003345:Corticosterone / Q000097:blood*; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology; D009022:Morphine Derivatives / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D011957:Receptors, Opioid / Q000187:drug effects*; D013312:Stress, Physiological / Q000097:blood*; D013997:Time Factors
D009022:Morphine Derivatives; D011957:Receptors, Opioid; D009270:Naloxone; D009020:Morphine; D003345:Corticosterone