Zhang Yu, Zeng Xiao-rong, Yang Yan, Zhang Biao, Liu Zhi-fei, Li Miao-ling, Zhou Wen, Pei Jie
Institute of Myocardium Electrophysiology, Luzhou Medical College, Luzhou 646000, Sichuan, China.
Zhonghua Xin Xue Guan Bing Za Zhi. 2006 Jan;34(1):33-7.
To compare the changes of both inward rectifying K(+) (Kir) current(I(k1)) density and mRNA expression level of Kir2.1, a major subfamily of Kir in chronic human atrial fibrillation (CAF) with those in normal sinus rhythm (NSR).
I(k1) density was measured with whole-cell patch clamp technique in single myocyte isolated by an enzymatic dissociation method from right atrial appendages in patients with CAF (n = 8) and those with NSR (n = 12). The mRNA expression levels of Kir2.1 was determined in right atrial appendages from CAF (n = 19) and NSR (n = 18) by semiquantitative reverse-transcription polymerase chain reaction (RT-PCR).
The average resting membrane potentials were similar between CAF and NSR (-78.95 mV +/- 4.67 mV and -70.22 mV +/- 11.08 mV, P>0.05). I(k1) density in single myocyte significantly increased at hyperpolarized potential level (-100 mV) in CAF compared to that in NSR (-9.59 pA/pF +/- 2.47 pA/pF vs. -5.58 pA/pF +/- 2.52 pA/pF, P<0.01). The mRNA level of Kir2.1 was also significantly higher in CAF than that of NSR (0.50+/-0.16 vs. 0.34+/-0.09, P<0.05).
The data suggest that Kir2.1 up-regulation and I(k1) current increase might contribute to the electrical remodeling in CAF patients.
比较慢性持续性心房颤动（CAF）患者与正常窦性心律（NSR）者内向整流钾（K(+)）电流（I(k1)）密度及Kir主要亚家族Kir2.1的mRNA表达水平的变化。
采用全细胞膜片钳技术，测量通过酶解法从CAF患者（n = 8）和NSR患者（n = 12）右心耳分离的单个心肌细胞的I(k1)密度。采用半定量逆转录聚合酶链反应（RT-PCR）测定CAF患者（n = 19）和NSR患者（n = 18）右心耳中Kir2.1的mRNA表达水平。
CAF组和NSR组的平均静息膜电位相似（-78.95 mV ± 4.67 mV和-70.22 mV ± 11.08 mV，P>0.05）。与NSR组相比，CAF组单个心肌细胞在超极化电位水平（-100 mV）时I(k1)密度显著增加（-9.59 pA/pF ± 2.47 pA/pF 对 -5.58 pA/pF ± 2.52 pA/pF，P<0.01）。CAF组Kir2.1的mRNA水平也显著高于NSR组（0.50±0.16对0.34±0.09，P<0.05）。
数据表明，Kir2.1上调和I(k1)电流增加可能促成了CAF患者的电重构。
