Barium chloride impaired Kir2.1 inward rectification in its stably transfected HEK 293 cell lines

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• 作者：Naiji Shen^a ; ¹ ; Jifeng Zheng^b ; ¹ ; Hualiang Liu^c ; ¹ ; Kai Xu^d ; Qingmao Chen^d ; Yingying Chen^e ; Yueliang Shen^e ; Liqing Jiang^b ; Yuan Chen^c ; ^{ychen@zafu.edu.cn" class="auth_mail}
• 关键词：Kir2.1 ; Inward rectify ; Barium ; Cardiac action potential ; Outward current
• 刊名：European Journal of Pharmacology
• 出版年：5 May, 2014
• 年：2014
• 卷：730
• 期：Complete
• 页码：164-170
• 全文大小：1145 K

文摘

Kir2.1 channel is a typical inward rectified channel with little outward currents when the membrane depolarized. Barium blocks the inward Kir2.1 currents in a voltage-dependent manner. However, in this study we found that barium would impair the rectification and open Kir2.1 outward currents at a depolarized voltage, causing increment of outward current amplitudes by 43卤7% (n=5, P<0.01) after 200 s barium application. In the meanwhile, a higher barium concentration did block the outward currents by 17.5卤4.3% (n=4, P<0.01) and temporarily twisted current upward tendency. The increment was likely barium specific since both calcium and Kir2.1 specific blocker, Chloroethylclonidine (CEC), did not enhance the current amplitudes. The rectification of Kir2.1 was not recovered by washing barium off, which suggested a non-competitive mechanism. Since the currents occurred at phase 1, 2 of cardiac action potential, it would likely shorten the action potential plateau and it would decrease QT duration in electrocardiography (ECG).