title: Nonspecific effects of ligands on the beta-adrenergic receptors in rabbit abdominal aorta in vitro.
abstract: The study was conducted on 30 New Zealand rabbits weighing 3-4 kg from which sample strips of the abdominal aorta were collected. The study investigated the in vitro reaction of rabbit aorta smooth muscle to ligands binding to beta-adrenergic receptors. The response of aortic strips to beta-adrenergic receptor agonists (dobutamine, isoproterenol, salbutamol) and the influence of beta-adrenergic receptor antagonists (propranolol, betaxolol) on contractile activity was determined. All tested agonists induced contraction of the rabbit abdominal aorta muscle in a concentration-dependent manner (dobutamine >> isoproterenol > salbutamol). Enhanced reaction to low concentrations of agonists (dobutamine, isoproterenol) after administration of propranolol and inhibition of contractility in the presence of high concentrations thereof (dobutamine, salbutamol) was observed. Maximal reaction to agonists decreased after betaxolol pretreatment. The results indicate that all the substances with beta-agonist activity also possess contracting properties (presumably by acting at alpha-adrenergic receptors), but are much weaker in the case of isoproterenol and salbutamol than for dobutamine. Propranolol and betaxolol reduce the contractile response of smooth muscle using probably other mechanisms than those associated with adrenergic receptors.
authors.affiliation: Wrovasc - Integrated Cardiovascular Centre, Kamieńskiego 73/a, 51-124 Wrocław, Poland.
authors.forename: Jan
authors.initials: J
authors.lastname: Gnus
authors.forename: Albert
authors.initials: A
authors.lastname: Czerski
authors.forename: Jolanta
authors.initials: J
authors.lastname: Bujok
authors.forename: Stanisław
authors.initials: S
authors.lastname: Ferenc
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zawadzki
authors.forename: Wojciech
authors.initials: W
authors.lastname: Witkiewicz
authors.forename: Willy
authors.initials: W
authors.lastname: Hauzer
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Rusiecka
authors.forename: Maciej
authors.initials: M
authors.lastname: Janeczek
mesh_terms: D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D011817:Rabbits; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta