title: Inhibitory action of kaurenoic acid from Viguiera robusta (Asteraceae) on phenylephrine-induced rat carotid contraction.
abstract: ent-kaurenoic acid (KA) isolated from Viguiera robusta was tested for activity on vascular smooth muscle contactility. Cumulative concentration-response curves were obtained for a stepwise increase (10(-10)-10(-05) mol/l) in the concentration of phenylephrine (Phe), a selective alpha(1)-adrenergic agonist. The effects in the presence of KA (0.2, 2.0 and 20.0 microg/ml), and 90 min after the removal of KA from the medium bath were compared to controls. At 20.0 microg/ml, KA inhibited the in vitro contractility of rat carotid artery elicited by Phe, but had no effect at lower concentrations (0.2 and 2.0 microg/ml). The effect elicited by KA was reversible after 90 minutes.
authors.affiliation: USP, Faculdade de Medicina de Ribeirão Preto, Departamento de Farmacologia, São Paulo, Brazil.
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Tirapelli
authors.forename: Sergio R
authors.initials: SR
authors.lastname: Ambrosio
authors.forename: Fernando B
authors.initials: FB
authors.lastname: Da Costa
authors.forename: Ana M
authors.initials: AM
authors.lastname: De Oliveira
mesh_terms: D000818:Animals; D019659:Asteraceae; D002339:Carotid Arteries / Q000187:drug effects*; D004224:Diterpenes / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D010656:Phenylephrine; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D014662:Vasoconstrictor Agents / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D004224:Diterpenes; D010936:Plant Extracts; D014662:Vasoconstrictor Agents; D010656:Phenylephrine; C051436:kaurenoic acid