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Arbutus unedo induces endothelium‐dependent relaxation of the isolated rat aorta

2002; Wiley; Volume: 16; Issue: 6 Linguagem: Inglês

10.1002/ptr.1143

1099-1573

Abderrahim Ziyyat, Hassane Mekhfi, Mohamed Bnouham, Abdelhafid Tahri, Abdelkhaleq Legssyer, Jacqueline Hoerter, Rodolphe Fischmeister,

Synthesis and Reactions of Organic Compounds

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 μ M N G ‐methyl‐ L ‐arginine ( L ‐NMA), 10 μ M methylene blue or 50 μ M 1H‐[1,2,4] oxadiazolo [4,3‐a] quinoxaline‐1‐one (ODQ) but not by 10 μ M 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. Copyright © 2002 John Wiley & Sons, Ltd.