title: Morphine no longer blocks gastrointestinal transit but retains antinociceptive action in diallylnormorphine-pretreated rats.
abstract: Diallylnormorphine (DANM) the quaternary N-allyl derivative of nalorphine, administered to rats, 8 mg/kg i.p., 20 min before i.v. injection of the potent opiate buprenorphine (1 microgram/kg, tritrium-labeled), reduced in vivo binding of the latter (63% of controls at 30 min) in small intestine longitudinal muscle including myenteric plexus, but not in cerebrum. Naloxone, 1 mg/kg s.c., had the same effect of buprenorphine binding in the two sites (52 and 54% of controls respectively). The marked slowing in the transit of a forced charcoal meal through the small intestine of rats given 10 mg/kg morphine, i.v. was prevented to comparable extents by DANM and naloxone; the latter also abolished the delay in hot plate reaction induced in these animals by morphine which, however, retained considerable antinociceptive effect in DANM-pretreated rats.
mesh_terms: D000700:Analgesics; D000818:Animals; D002047:Buprenorphine / Q000378:metabolism; D005769:Gastrointestinal Motility / Q000187:drug effects*; D008297:Male; D009020:Morphine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009269:Nalorphine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D051381:Rats
chemical_list: D000700:Analgesics; D009270:Naloxone; D002047:Buprenorphine; D009020:Morphine; D009269:Nalorphine