title: The role of spinal muscarinic acetylcholine receptors in clonidine-induced anti-nociceptive effects in rats.
abstract: We have examined the effects of intrathecal (i.t.) injection of the muscarinic acetylcholine receptor antagonist atropine on the clonidine-induced nociceptive effect in formalin-induced nociception in rats. The injection of 5% formalin into the hind paw caused biphasic nociceptive responses, and i.t. injection of clonidine inhibited both phases of the nociceptive response in a dose-dependent manner. Pretreatment with atropine (i.t.) only partially inhibited the nociceptive effect of clonidine. These results suggest that the nociceptive effect of clonidine in the rat formalin model may be at least partly mediated by muscarinic acetylcholine receptors in the spinal cord.
authors.affiliation: Department of Physiology and Pharmacology, Faculty of Pharmaceutical Science, Fukuoka University, Fukuoka, Japan. khonda@fukuoka-u.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Honda
authors.forename: Namiko
authors.initials: N
authors.lastname: Murao
authors.forename: Takae
authors.initials: T
authors.lastname: Ibuki
authors.forename: Hiro-O
authors.initials: HO
authors.lastname: Kamiya
authors.forename: Yukio
authors.initials: Y
authors.lastname: Takano
mesh_terms: D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D003000:Clonidine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D010147:Pain Measurement / Q000187:drug effects* / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000502:physiology*; D013116:Spinal Cord
chemical_list: D000700:Analgesics; D011976:Receptors, Muscarinic; D003000:Clonidine