title: Interactions between phenylephrine, clonidine and xylazine in rat and rabbit aortas.
abstract: The interaction of the alpha 2-adrenoceptor agonists clonidine and xylazine with the alpha 1-adrenoceptors in the rat and rabbit aortas was investigated. In preparations preconstricted with phenylephrine (10(-6) M), cumulative addition of clonidine and xylazine induced concentration-related vasodilatation in the presence of the alpha 2-adrenoceptor antagonist yohimbine and the beta-blocker propranolol. Neither clonidine nor xylazine treatment inhibited 5-HT- and KCl-induced vasoconstriction. It is concluded that alpha 2-agonists have affinity for alpha 1-adrenoceptors in rat and rabbit aortas.
authors.affiliation: Department of Pharmacology, Faculty of Medicine, University of Selçuk, Konya, Turkey.
authors.forename: K E
authors.initials: KE
authors.lastname: Atalik
authors.forename: A S
authors.initials: AS
authors.lastname: Sahin
authors.forename: N
authors.initials: N
authors.lastname: Doğan
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D003000:Clonidine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D010656:Phenylephrine / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D014664:Vasodilation / Q000187:drug effects; D014991:Xylazine / Q000494:pharmacology*
chemical_list: D000316:Adrenergic alpha-Agonists; D010656:Phenylephrine; D014991:Xylazine; D003000:Clonidine