title: Arbutus unedo induces endothelium-dependent relaxation of the isolated rat aorta.
abstract: Arbutus unedo L. (Ericaceae) is used in oriental Morocco to treat arterial hypertension. We studied its vasodilator effect and mechanisms of action in vitro. The root aqueous extract of Arbutus (0.25 mg/mL) produced a relaxation of noradrenaline-precontracted ring preparations of rat aorta with intact endothelium. Relaxation by Arbutus did not occur in specimens without endothelium and was inhibited by pretreatment with 100 microM N(G)-methyl-L-arginine (L-NMA), 10 microM methylene blue or 50 microM 1H-[1,2,4] oxadiazolo [4,3-a] quinoxaline-1-one (ODQ) but not by 10 microM atropine. These results suggest that Arbutus produces an endothelium-dependent relaxation of the isolated rat aorta which may be mediated mainly by a stimulation of the endothelial nitric oxide synthase by mechanisms other than activation of muscarinic receptors.
authors.affiliation: Laboratoire de Physiologie et Pharmacologie Cellulaire, Département de Biologie, Faculté des Sciences, Université Mohamed Premier, BP 524, Route Sidi Maafa, 60000 Oujda, Maroc. ziyyat@sciences.univ-oujda.ac.ma
authors.forename: Abderrahim
authors.initials: A
authors.lastname: Ziyyat
authors.forename: Hassane
authors.initials: H
authors.lastname: Mekhfi
authors.forename: Mohamed
authors.initials: M
authors.lastname: Bnouham
authors.forename: Abdelhafid
authors.initials: A
authors.lastname: Tahri
authors.forename: Abdelkhaleq
authors.initials: A
authors.lastname: Legssyer
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Hoerter
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Fischmeister
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000008:administration & dosage; D004285:Dogs; D004347:Drug Interactions; D004730:Endothelium, Vascular / Q000502:physiology*; D029791:Ericaceae; D066298:In Vitro Techniques; D008297:Male; D008751:Methylene Blue / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D010069:Oxadiazoles / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
chemical_list: C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D010069:Oxadiazoles; D010936:Plant Extracts; D011810:Quinoxalines; D001285:Atropine; D002217:Carbachol; D008751:Methylene Blue; D019331:NG-Nitroarginine Methyl Ester; D009638:Norepinephrine