title: Contraction of isolated porcine coronary arteries is inhibited by high concentrations of propranolol.
abstract: Isometric tension responses of isolated porcine coronary artery rings were studied in the presence of concentrations of propranolol higher than those necessary to block effects mediated by beta-adrenergic receptors. Propranolol (50-300 microM) inhibited contractions induced by 30 mM KCl and by histamine, norepinephrine, and acetylcholine in a concentration-dependent, noncompetitive fashion. The (+) propranolol isomer and the racemic mixture were equipotent inhibitors of contraction. Propranolol inhibition was partly reversed by increased extracellular Ca++. These effects of propranolol thus appeared to be independent of beta-blockade and could be relevant to some of the drug's observed but still unexplained in vivo actions.
authors.affiliation: Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
authors.forename: E L
authors.initials: EL
authors.lastname: Carey
authors.forename: D
authors.initials: D
authors.lastname: Robertson
authors.forename: J N
authors.initials: JN
authors.lastname: Wells
authors.forename: R M
authors.initials: RM
authors.lastname: Robertson
mesh_terms: D000109:Acetylcholine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects* / Q000502:physiology; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D006632:Histamine / Q000494:pharmacology; D006633:Histamine Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology*; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D006633:Histamine Antagonists; D006632:Histamine; D011433:Propranolol; D000109:Acetylcholine; D009638:Norepinephrine