title: Study on the histamine-like activity of guanfacine.
abstract: The effects of guanfacine have been studied on guinea-pig isolated atria and diethylstilboestrol-treated rat isolated uterus to determine whether it possesses histamine-like activity. Guanfacine produced a concentration-dependent negative chronotropic effect which was not modified by ranitidine (0.1 microM). In rat isolated uterus contracted by KCl, clonidine (5-5000 microM) produced concentration-dependent relaxation which was blocked by ranitidine (0.1 microM), but guanfacine only produced relaxation at high concentrations (100-1000 microM), and this was not affected by ranitidine (0.1 microM). It is concluded that guanfacine, unlike clonidine, does not produce effects due to activation of H2-receptors in either guinea-pig atria or rat uterus.
authors.affiliation: Departament de Farmacologia i Farmacotecnia, Universitat de Valencia, España.
authors.forename: M I
authors.initials: MI
authors.lastname: Martinez-Mir
authors.forename: F
authors.initials: F
authors.lastname: Doñate
authors.forename: L
authors.initials: L
authors.lastname: Estañ
authors.forename: F J
authors.initials: FJ
authors.lastname: Morales-Olivas
authors.forename: E
authors.initials: E
authors.lastname: Rubio
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D004054:Diethylstilbestrol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D016316:Guanfacine / Q000494:pharmacology*; D006168:Guinea Pigs; D006325:Heart Atria / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014590:Uterine Contraction / Q000187:drug effects*
chemical_list: D000316:Adrenergic alpha-Agonists; D016316:Guanfacine; D011189:Potassium Chloride; D004054:Diethylstilbestrol; D003000:Clonidine