Antagonism of morphine-induced behavioral suppression by opiate receptor alkylators.
Experiments were conducted to test the in vivo opiate specificity and long-lasting effects of two non-equilibrium opiate antagonists: beta-chlornaltrexamine (beta-CNA) and the beta-fumarate methyl ester derivative of naltrexone (beta-FNA). beta-CNA (2.5 or 5.0 micrograms, ICV) partially antagonized suppression of conditioned autoshaped behavior by morphine, when morphine was administered 48-72 hr after beta-CNA. beta-CNA had no effect on amphetamine-induced suppression of autoshaped responding, nor did it antagonize the suppression in rearing activity induced by either morphine or amphetamine. Similarly, beta-FNA (5 mg/kg, IP) antagonized the suppression of conditioned behavior by morphine, for up to 48 hr, while having no effect on amphetamine-induced suppression of autoshaped responding, or on the suppression of rearing activity induced by morphine or amphetamine. Further peripherally administered beta-FNA acts in the brain, since it antagonized analgesia following ICV morphine administration.
D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects*; D005106:Exploratory Behavior / Q000187:drug effects*; D008297:Male; D009020:Morphine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D009115:Muridae; D009270:Naloxone / Q000031:analogs & derivatives*; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009588:Nitrogen Mustard Compounds / Q000494:pharmacology; D009619:Nociceptors / Q000187:drug effects; D011957:Receptors, Opioid / Q000187:drug effects*
D009588:Nitrogen Mustard Compounds; D011957:Receptors, Opioid; D009270:Naloxone; D009271:Naltrexone; C017120:chlornaltrexamine; C024524:beta-funaltrexamine; D009020:Morphine; D000661:Amphetamine