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

Research output: Contribution to journalArticle

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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 (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.

Original languageEnglish
Pages (from-to)2379-2387
Number of pages9
JournalLife Sciences
Volume74
Issue number19
DOIs
Publication statusPublished - Mar 26 2004

Fingerprint

Potassium Channels
Wistar Rats
Rats
KATP Channels
Vasodilator Agents
Vasopressins
Vasodilation
Endothelium
Small-Conductance Calcium-Activated Potassium Channels
Stevia
Potassium Channel Blockers
isosteviol
Sweetening Agents
Potassium Chloride
Methylene Blue
Vasoconstriction
Brazil
Potassium
Japan
Nitric Oxide

Keywords

  • Aortic rings
  • Isosteviol
  • Potassium channel blockers
  • Stevia rebaudiana

ASJC Scopus subject areas

  • Pharmacology

Cite this

Isosteviol acts on potassium channels to relax isolated aortic strips of Wistar rat. / Wong, Kar L.; Chan, Paul; Yang, Hung Y.; Hsu, Feng-Lin; Liu, I. M.; Cheng, Yu W.; Cheng, Juei Tang.

In: Life Sciences, Vol. 74, No. 19, 26.03.2004, p. 2379-2387.

Research output: Contribution to journalArticle

Wong, Kar L. ; Chan, Paul ; Yang, Hung Y. ; Hsu, Feng-Lin ; Liu, I. M. ; Cheng, Yu W. ; Cheng, Juei Tang. / Isosteviol acts on potassium channels to relax isolated aortic strips of Wistar rat. In: Life Sciences. 2004 ; Vol. 74, No. 19. pp. 2379-2387.
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