Effect of morphinone on opiate receptor binding and morphine-elicited analgesia.
Specific binding of 3H-naloxone to opiate receptors was found to be irreversibly inactivated by morphine. This inactivation exhibited pseudo-first-order kinetics. The presence of sulfhydryl compounds or morphine during incubation with morphinone proved good protection. Morphinone-pretreated mice blocked the analgesic effect of morphine. The possible mechanism for these observations is proposed as follows: morphinone binds covalently to sulfhydryl group of opiate receptors, and inactivates irreversibly opiate binding sites, thus blocking the analgesic effect of morphine.
D000698:Analgesia; D000818:Animals; D003545:Cysteine / Q000494:pharmacology; D004090:Dihydromorphine / Q000494:pharmacology; D005978:Glutathione / Q000494:pharmacology; D004091:Hydromorphone / Q000031:analogs & derivatives* / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000378:metabolism*; D011957:Receptors, Opioid / Q000187:drug effects / Q000378:metabolism*
D011957:Receptors, Opioid; C036083:morphinone; D009270:Naloxone; D009020:Morphine; D004090:Dihydromorphine; D005978:Glutathione; D003545:Cysteine; D004091:Hydromorphone