Decrease of morphine-induced prolactin release by a procedure causing prolonged stress.
The effects of morphine and fentanyl on plasma prolactin levels in rats have been measured. It was found that a prolonged immobilization stressful procedure for 5 h inhibited the response to morphine and fentanyl to increase prolactin secretion, but did not influence the increase in plasma prolactin caused by haloperidol. The injection of a large dose of cortisol (25 mg/kg, s.c.) also evoked an inhibition of morphine-induced prolactin release. The inhibition was maximal 24 h after the administration of the glucocorticoid. These results indicate that stress may induce prolonged alteration in endogenous opioid-mediated neuromodulation via a prolonged release of glucocorticoids.
D000818:Animals; D003864:Depression, Chemical; D005283:Fentanyl / Q000494:pharmacology; D006220:Haloperidol / Q000494:pharmacology; D006854:Hydrocortisone / Q000494:pharmacology; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000097:blood / Q000503:physiopathology*; D013997:Time Factors
D009020:Morphine; D011388:Prolactin; D006220:Haloperidol; D005283:Fentanyl; D006854:Hydrocortisone