Isosteviol acts on potassium channels to relax isolated aortic strips of Wistar rat

Kar L. Wong; Paul Chan; Hung Y. Yang; Feng-Lin Hsu; I. M. Liu; Yu W. Cheng; Juei Tang Cheng

doi:10.1016/j.lfs.2003.09.065

Isosteviol acts on potassium channels to relax isolated aortic strips of Wistar rat

Kar L. Wong, Paul Chan, Hung Y. Yang, Feng-Lin Hsu, I. M. Liu, Yu W. Cheng, Juei Tang Cheng

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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 (3×10^-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.

Original language	English
Pages (from-to)	2379-2387
Number of pages	9
Journal	Life Sciences
Volume	74
Issue number	19
DOIs	https://doi.org/10.1016/j.lfs.2003.09.065
Publication status	Published - Mar 26 2004

Keywords

Aortic rings
Isosteviol
Potassium channel blockers
Stevia rebaudiana

ASJC Scopus subject areas

General Pharmacology, Toxicology and Pharmaceutics
General Biochemistry,Genetics and Molecular Biology

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10.1016/j.lfs.2003.09.065

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title = "Isosteviol acts on potassium channels to relax isolated aortic strips of Wistar rat",

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 (3×10-2 M), the vasodilator effect of isosteviol on arterial strips disappeared. Only the inhibitors specific for the ATP-sensitive potassium (KATP) channel or small conductance calcium-activated potassium (SKCa) 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 KATP channels.",

keywords = "Aortic rings, Isosteviol, Potassium channel blockers, Stevia rebaudiana",

author = "Wong, {Kar L.} and Paul Chan and Yang, {Hung Y.} and Feng-Lin Hsu and Liu, {I. M.} and Cheng, {Yu W.} and Cheng, {Juei Tang}",

note = "Funding Information: We acknowledge Professor Brian Tomlinson for editing and Professor Die-Yi Xu (Nanjing Railway College of Medicine, Nanjing City, China) for kindly supply of stevioside. The present study is supported in part by a grant from National Science Council of the Republic of China (NSC88-2314-B038-130).",

year = "2004",

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doi = "10.1016/j.lfs.2003.09.065",

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T1 - Isosteviol acts on potassium channels to relax isolated aortic strips of Wistar rat

AU - Wong, Kar L.

AU - Chan, Paul

AU - Yang, Hung Y.

AU - Hsu, Feng-Lin

AU - Liu, I. M.

AU - Cheng, Yu W.

AU - Cheng, Juei Tang

N1 - Funding Information: We acknowledge Professor Brian Tomlinson for editing and Professor Die-Yi Xu (Nanjing Railway College of Medicine, Nanjing City, China) for kindly supply of stevioside. The present study is supported in part by a grant from National Science Council of the Republic of China (NSC88-2314-B038-130).

PY - 2004/3/26

Y1 - 2004/3/26

N2 - 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 (3×10-2 M), the vasodilator effect of isosteviol on arterial strips disappeared. Only the inhibitors specific for the ATP-sensitive potassium (KATP) channel or small conductance calcium-activated potassium (SKCa) 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 KATP channels.

AB - 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 (3×10-2 M), the vasodilator effect of isosteviol on arterial strips disappeared. Only the inhibitors specific for the ATP-sensitive potassium (KATP) channel or small conductance calcium-activated potassium (SKCa) 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 KATP channels.

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KW - Isosteviol

KW - Potassium channel blockers

KW - Stevia rebaudiana

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ER -

Isosteviol acts on potassium channels to relax isolated aortic strips of Wistar rat

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