title: Potentiation of imipramine-induced antinociception by nicotine in the formalin test.
abstract: In this study, the effect of cholinergic agents on imipramine antinociception in mice, in the formalin test, has been investigated. Intraperitoneal (i.p.) administration of different doses of imipramine (2.5, 5, 10, 20 and 30 mg/kg) or nicotine (0.25, 0.5, 0.75 and 1 mg/kg) induced a dose dependent antinociception in both the first and second phases of the formalin test in mice. The combination of imipramine with doses of 0.5 and 0.75 mg/kg of nicotine showed a potentiated response, in both phases of the test. However, neither hexamethonium (5 and 10 mg/kg), atropine (0.25 mg/kg) or mecamylamine (0.25 mg/kg) altered the antinociception induced by imipramine. It is concluded that nicotinic receptor activation but not the cholinergic muscarinic mechanism is involved in the imipramine-induced antinociception.
authors.affiliation: Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box 13145-784 Tehran, Iran. zarinmr@ams.ac.ir
authors.forename: Mohammad-Reza
authors.initials: MR
authors.lastname: Zarrindast
authors.forename: Banafsheh
authors.initials: B
authors.lastname: Baghdadi
authors.forename: Mousa
authors.initials: M
authors.lastname: Sahebgharani
mesh_terms: D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D007099:Imipramine / Q000494:pharmacology*; D008297:Male; D051379:Mice; D009538:Nicotine / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects* / Q000379:methods
chemical_list: D000700:Analgesics; D009538:Nicotine; D007099:Imipramine