title: Effect of mu and kappa opioid receptor agonists on rat plasma corticosterone levels.
abstract: The effect of several mu and kappa opioid receptor agonists on rat plasma corticosterone levels, measured using radioimmunoassay, was investigated. The mu agonists, morphine and fentanyl, and the kappa agonists, U-50,488, tifluadom and bremazocine, all produced dose-related increases in rat plasma corticosterone levels. The effects of both fentanyl and U-50,488 were reversed by naloxone, indicating an action at opioid receptors. Pretreatment of the rats with the irreversible, mu-selective antagonist, beta-funaltrexamine, reduced the effect of fentanyl, but not that of U-50,488, indicating that both mu and kappa opioid receptors are involved in mediating this effect.
mesh_terms: D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000818:Animals; D001569:Benzodiazepines / Q000494:pharmacology; D001575:Benzomorphans / Q000494:pharmacology; D003345:Corticosterone / Q000097:blood*; D004305:Dose-Response Relationship, Drug; D005283:Fentanyl / Q000494:pharmacology; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D051381:Rats; D011957:Receptors, Opioid / Q000187:drug effects / Q000378:metabolism*; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu
chemical_list: D001575:Benzomorphans; D011759:Pyrrolidines; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D001569:Benzodiazepines; D009270:Naloxone; D009271:Naltrexone; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; C024524:beta-funaltrexamine; D009020:Morphine; C027248:bremazocine; C035470:tifluadom; D005283:Fentanyl; D003345:Corticosterone