Isosteviol acts on potassium channels to relax isolated aortic strips of Wistar rat |
| |
Authors: | Wong Kar-Lok Chan Paul Yang Hung-Yu Hsu Feng-Lin Liu I-Min Cheng Yu-Wan Cheng Juei-Tang |
| |
Affiliation: | Graduate Institute of Medical Science, Taipei Medical University, Taipei 106, Taiwan. |
| |
Abstract: | Isosteviol is a derivative of stevioside, a constituent of Stevia rebaudiana, which is commonly used as a noncaloric sugar substitute in Japan and Brazil. In the present study, the role of potassium channels in the vasodilator effect of isosteviol was investigated using potassium channel blockers on isosteviol-induced relaxation of isolated aortic rings prepared from Wistar rats. Isosteviol dose-dependently relaxed the vasopressin (10(-8) M)-induced vasoconstriction in isolated aortic rings with or without endothelium. However, in the presence of potassium chloride (3x10(-2) M), the vasodilator effect of isosteviol on arterial strips disappeared. Only the inhibitors specific for the ATP-sensitive potassium (K(ATP)) channel or small conductance calcium-activated potassium (SK(Ca)) channel inhibited the vasodilator effect of isosteviol in isolated aortic rings contracted with 10(-8) M vasopressin. Also; since the isosteviol-induced relaxation was unchanged by methylene blue, a role of nitric oxide and/or endothelium in the vasodilatation produced by isosteviol could be ruled out. The obtained results indicated that vasodilatation induced by isosteviol is related to the opening of SK(Ca) and K(ATP) channels. |
| |
Keywords: | Isosteviol Stevia rebaudiana Potassium channel blockers Aortic rings |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|