title: The effects of endocannabinoid receptor agonist anandamide and antagonist rimonabant on opioid analgesia and tolerance in rats.
abstract: The role of the cannabinoid (CB) system in the tolerance to analgesic effect of opioid remains obscure. The aim of the present study was to evaluate the effects of the endocannabinoid nonselective receptor agonist anandamide (AEA) and CB1 receptor antagonist rimonabant (SR141716) on morphine analgesia and tolerance in rats. Male Wistar albino rats weighing 215-230 g were used in these experiments. To constitute morphine analgesic tolerance, a 3-day cumulative dosing regimen was used. The analgesic effects of AEA (10 mg/kg), SR141716 (10 mg/kg), and morphine (5 mg/kg) were considered at 30-min intervals by tail flick (TF) and hot plate (HP) analgesia tests. The analgesic effects of the drugs were measured as TF and HP latencies in all groups for each rat and converted to %MPE. The data were analysed by analysis of variance followed by Tukey test. The findings suggested that AEA in combination with morphine produced a significant increase in expression of analgesic tolerance to morphine. Conversely, cannabinoid receptor antagonist SR141716 attenuated morphine analgesic tolerance. In addition, administration of AEA with morphine increased morphine analgesia. In conclusion, we observed that the cannabinoid receptor agonist anandamide and CB1 receptor antagonist SR141716 plays a significant role in the opioid analgesia and tolerance.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Altun
authors.forename: Ercan
authors.initials: E
authors.lastname: Ozdemir
authors.forename: Kemal
authors.initials: K
authors.lastname: Yildirim
authors.forename: Sinan
authors.initials: S
authors.lastname: Gursoy
authors.forename: Nedim
authors.initials: N
authors.lastname: Durmus
authors.forename: Ihsan
authors.initials: I
authors.lastname: Bagcivan
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage; D000818:Animals; D001095:Arachidonic Acids / Q000008:administration & dosage*; D063386:Cannabinoid Receptor Agonists / Q000008:administration & dosage; D063387:Cannabinoid Receptor Antagonists / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004361:Drug Tolerance / Q000502:physiology; D063388:Endocannabinoids / Q000008:administration & dosage*; D008297:Male; D009020:Morphine / Q000008:administration & dosage*; D059225:Nociception / Q000187:drug effects* / Q000502:physiology*; D010880:Piperidines / Q000008:administration & dosage*; D053284:Polyunsaturated Alkamides / Q000008:administration & dosage*; D011720:Pyrazoles / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar; D000077285:Rimonabant; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid; D001095:Arachidonic Acids; D063386:Cannabinoid Receptor Agonists; D063387:Cannabinoid Receptor Antagonists; D063388:Endocannabinoids; D010880:Piperidines; D053284:Polyunsaturated Alkamides; D011720:Pyrazoles; D009020:Morphine; D000077285:Rimonabant; C078814:anandamide