title: Caerulein may potentiate morphine-induced antinociception by cholecystokinin-A and/or cholecystokinin-B receptor mechanisms.
abstract: 1. The effects of a cholecystokinin agonist and antagonist on morphine antinociception in the tail-flick test have been evaluated. 2. The administration of different doses of caerulein (0.01, 0.05 and 0.1 mg/kg) 30 min prior to morphine (1.5, 3 and 6 mg/kg) increased the antinociception induced by morphine in mice. 3. In animals pretreated with cholecystokinin antagonists MK-329 (0.125 and 0.25 mg/kg) and L-365,260 (0.125 and 0.25 mg/kg), the antinociceptive effect of morphine was not changed. However, high doses (0.5 mg/kg) of each antagonist potentiated the morphine response. 4. Low doses of cholecystokinin antagonists (0.125 and 0.25 mg/kg), that did not cause antinociception, when employed in combination with caerulein (0.05 mg/kg) decreased the response of morphine plus caerulein. 5. It is concluded that the cholecystokinin agonist caerulein potentiated the morphine response by stimulation of cholecystokinin-A and/or cholecystokinin-B receptors.
authors.affiliation: Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Rezayat
authors.forename: S
authors.initials: S
authors.lastname: Oreizi
authors.forename: M R
authors.initials: MR
authors.lastname: Zarrindast
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology; D002108:Ceruletide / Q000494:pharmacology*; D002766:Cholecystokinin / Q000037:antagonists & inhibitors*; D020109:Devazepide; D004357:Drug Synergism; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects; D010671:Phenylurea Compounds; D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors / Q000502:physiology
chemical_list: D000701:Analgesics, Opioid; D001570:Benzodiazepinones; D010671:Phenylurea Compounds; D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin; C058121:L 365260; D009020:Morphine; D002108:Ceruletide; D002766:Cholecystokinin; D020109:Devazepide