title: Baclofen-induced antinociception and nicotinic receptor mechanism(s).
abstract: In this study, the influences of nicotinic receptor agents on baclofen-induced antinociception in the tail-flick test have been studied. Intraperitoneal administration of baclofen (2.5, 5 and 10 mg/kg) to mice induced a dose-dependent antinociception in the tail-flick test. Subcutaneous injection of nicotine (0.5-2.5 mg/kg) also caused a dose-dependent antinociceptive response. Intracerebral (10 and 20 microg/mouse) but not intraperitoneal administration of hexamethonium (5 and 10 mg/kg) to mice decreased the response of both nicotine and baclofen. However, administration of the GABA(B) antagonist CGP 35348 (100 and 200 mg/kg) decreased the response induced by baclofen but not by nicotine. It is concluded that at least part of the baclofen-induced antinociception may be mediated through a nicotinic mechanism.
authors.affiliation: Department of Pharmacology, School of Medicine, University of Shahid-Beheshti Medical Sciences, Tehran University of Medical Sciences, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Sabetkasai
authors.forename: S
authors.initials: S
authors.lastname: Ahang
authors.forename: B
authors.initials: B
authors.lastname: Shafaghi
authors.forename: M R
authors.initials: MR
authors.lastname: Zarrindast
mesh_terms: D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D001418:Baclofen / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D018756:GABA Antagonists / Q000494:pharmacology; D018738:Hexamethonium / Q000494:pharmacology*; D008297:Male; D051379:Mice; D009538:Nicotine / Q000008:administration & dosage / Q000494:pharmacology*; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D010147:Pain Measurement / Q000379:methods*; D011978:Receptors, Nicotinic / Q000502:physiology; D013997:Time Factors
chemical_list: D000700:Analgesics; D018756:GABA Antagonists; D009943:Organophosphorus Compounds; D011978:Receptors, Nicotinic; D018738:Hexamethonium; D009538:Nicotine; C066430:CGP 35348; D001418:Baclofen