title: Barium chloride impaired Kir2.1 inward rectification in its stably transfected HEK 293 cell lines.
abstract: 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±7% (n=5, P<0.01) after 200s barium application. In the meanwhile, a higher barium concentration did block the outward currents by 17.5±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).
authors.affiliation: Cardiovascular Division, Zhejiang Province People׳s Hospital, 158 Shangtang Road, Hangzhou 310014, PR China.
authors.forename: Naiji
authors.initials: N
authors.lastname: Shen
authors.affiliation: Cardiovascular Division, Jiaxing No. 2 Hospital, 1882 Central Circle Road South, Jiaxing 314001, PR China.
authors.forename: Jifeng
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Chinese Herb Medicine Division, The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang Agriculture and Forestry University, 88 North Circle Road, Lin'an 311300, PR China.
authors.forename: Hualiang
authors.initials: H
authors.lastname: Liu
authors.affiliation: Safety Pharmacology Division, Olivepharmasolutions Ltd., 333 Changhong Road, Wukang 313200, PR China.
authors.forename: Kai
authors.initials: K
authors.lastname: Xu
authors.affiliation: Safety Pharmacology Division, Olivepharmasolutions Ltd., 333 Changhong Road, Wukang 313200, PR China.
authors.forename: Qingmao
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Pathophysiolog department, Medical School, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Pathophysiolog department, Medical School, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Yueliang
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Cardiovascular Division, Jiaxing No. 2 Hospital, 1882 Central Circle Road South, Jiaxing 314001, PR China.
authors.forename: Liqing
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Chinese Herb Medicine Division, The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang Agriculture and Forestry University, 88 North Circle Road, Lin'an 311300, PR China. Electronic address: ychen@zafu.edu.cn.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Chen
mesh_terms: D017609:Barium Compounds / Q000494:pharmacology*; D002712:Chlorides / Q000494:pharmacology*; D055724:Electrophysiological Phenomena / Q000187:drug effects*; D057809:HEK293 Cells; D006801:Humans; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics* / Q000378:metabolism*; D014162:Transfection
chemical_list: D017609:Barium Compounds; D002712:Chlorides; C489461:Kir2.1 channel; D024661:Potassium Channels, Inwardly Rectifying; C024986:barium chloride
keywords: Barium; Cardiac action potential; Inward rectify; Kir2.1; Outward current