Planta Med 2014; 80(06): 465-472
DOI: 10.1055/s-0034-1368320
Biological and Pharmacological Activity
Original Papers
Georg Thieme Verlag KG Stuttgart · New York

Enhancement of Voltage-Gated K+ Channels and Depression of Voltage-Gated Ca2+ Channels Are Involved in Quercetin-Induced Vasorelaxation in Rat Coronary Artery

Xiaomin Hou
1   Department of Pharmacology, Shanxi Medical University, Taiyuan, Shanxi Province, China
,
Yu Liu
1   Department of Pharmacology, Shanxi Medical University, Taiyuan, Shanxi Province, China
,
Longgang Niu
2   Medical Functional Experimental Center, Shanxi Medical University, Taiyuan, Shanxi Province, China
,
Lijuan Cui
2   Medical Functional Experimental Center, Shanxi Medical University, Taiyuan, Shanxi Province, China
,
Mingsheng Zhang
1   Department of Pharmacology, Shanxi Medical University, Taiyuan, Shanxi Province, China
2   Medical Functional Experimental Center, Shanxi Medical University, Taiyuan, Shanxi Province, China
› Author Affiliations
Further Information

Publication History

received 03 January 2014
revised 16 February 2014

accepted 28 February 2014

Publication Date:
07 April 2014 (online)

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Abstract

Quercetin is one of the most common flavonoids in the human daily diet. Its affects the coronary artery, especially L-type voltage-gated Ca2+ channels and voltage-gated K+ channels in the arterial smooth muscle cells, which are poorly understood. The present experiments were designed to study the myogenic effect of quercetin and its possible underlying mechanisms in the rat coronary artery. A wire myograph was used to observe the myogenic effects. Arterial smooth muscle cells were freshly isolated from the rat coronary artery and the intracellular free Ca2+ concentration was measured with molecular probe fluo-4-AM. The effects of quercetin on L-type voltage-gated Ca2+ channels and voltage-gated K+ channels were studied using a whole-cell patch clamp. Quercetin (3–30 µM) produced a depression and relaxation on the contraction induced by KCl or the thromboxane A2 analog 9,11-Dideoxy-9α,11α-methanoepoxy prostaglandin F . The vasorelaxation was attenuated by 4-aminopyridine, a specific voltage-gated K+ channel inhibitor, but was not affected by the NG-nitro-L-arginine methylester ester (a nitric oxide synthesis inhibitor), glibenclamide (a ATP-activated K+ channel inhibitor), iberiotoxin (a Ca2+-activated K+ channel inhibitor), BaCl2 (an inward rectifier K+ channel inhibitor), or by endothelium denudation. At the same concentrations, quercetin reduced the KCl-induced elevation of the intracellular free Ca2+ concentration, inhibited the inward Ca2+ currents through L-type voltage-gated Ca2+ channels, and increased the outward K+ currents through voltage-gated K+ channels in the rat coronary artery smooth muscle cells. Collectively, our results demonstrate that quercetin possesses vasospasmolytic effects in RCA and suggest that depression of the Ca2+ influx through L-type voltage-gated Ca2+ channels and augmentation of voltage-gated K+ channel activity in the myocytes may underlie coronary relaxation.

Supporting Information