Heterogeneous Expression of Potassium Currents and Pacemaker Currents Potentially Regulates Arrhythmogenesis of Pulmonary Vein Cardiomyocytes
Heterogeneous Expression of Potassium Currents and Pacemaker Currents Potentially Regulates Arrhythmogenesis of Pulmonary Vein Cardiomyocytes
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DOI：
10.1111/j.1540-8167.2009.01480.x
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发表时间：
2009-09-01
影响因子：
2.7
通讯作者：
Chen, Shih-Ann
中科院分区：
文献类型：
--
作者：
Chen, Yao-Chang;Pan, Nan-Hung;Chen, Shih-Ann
简介：肺静脉（PV）起搏心肌细胞的决定因素和搏动率之间的关系尚未完全阐明。本研究旨在比较PV快、慢起搏心肌细胞的电生理特性。采用全细胞膜片钳技术检测动作电位、瞬时外向钾电流（I-to）、持续外向钾电流（I-Ksus）、快速延迟整流钾电流（I-Kr）、内向整流钾电流（I-K1）、起搏电流（I-f）、兔离体肺静脉单快电流和瞬时内向电流（>= 2.5 Hz）和慢速（<2.5 Hz）起搏心肌细胞。快速PV起搏心肌细胞（n = 66）具有较小的负最大舒张电位（-53 +/-1 mV vs-59 +/-1 mV，P <0.001）和舒张期去极化斜率（0.31 +/-0.02 V/sec vs 0.09 +/-0.01 V/sec，P <0.001）大于慢PV起搏心肌细胞（n = 65）。此外，PV搏动率与舒张期除极斜率和最大舒张期电位呈线性回归关系。与慢PV起搏心肌细胞相比，快PV起搏心肌细胞具有较小的I-to和I-K1，较大的I-f，但具有相似的I-Ksus，I-I-Kr和瞬时内向电流。然而，只有少数快（2/34）和慢（1/23）PV起搏心肌细胞含有钡敏感超极化激活的时间依赖性电流（I-KH）。结论：快、慢肺静脉起搏器具有不同的电生理特性。I-to、I-K1和I-f可能调节PV起搏心肌细胞的搏动频率。（J.E. Vasc Electrophysiol，第20卷，第100页）。1039 - 1045）。
Introduction: The relationship between the determining factors and beating rates of pulmonary vein (PV) pacemaker cardiomyocytes has not been fully elucidated. The purposes of this study were to compare the electrophysiological characteristics between PV fast and slow pacemaker cardiomyocytes.Methods: Whole-cell patch clamp was used to investigate the action potentials, transient outward currents (I-to), sustained outward potassium currents (I-Ksus), rapid delayed rectifier potassium currents (I-Kr), inward rectifier potassium current (I-K1), pacemaker currents (I-f), and transient inward currents in isolated rabbit PV single fast (>= 2.5 Hz) and slow (< 2.5 Hz) pacemaker cardiomyocytes.Results: The fast PV pacemaker cardiomyocytes (n = 66) had lesser negative maximum diastolic potential (-53 +/- 1 mV vs -59 +/- 1 mV, P < 0.001) and larger slope of diastolic depolarization (0.31 +/- 0.02 V/sec vs 0.09 +/- 0.01 V/sec, P < 0.001) than slow PV pacemaker cardiomyocytes (n = 65). Moreover, the PV beating rates correlated well with the slope of diastolic depolarization and maximum diastolic potential with a linear regression. As compared to those in slow PV pacemaker cardiomyocytes, the fast PV pacemaker cardiomyocytes had smaller I-to and I-K1, and larger I-f but with similar I-Ksus,I- I-Kr, and transient inward currents. However, only few fast (2/34) and slow (1/23) PV pacemaker cardiomyocytes contained barium-sensitive hyperpolarization-activated time-dependent current (I-KH)(.)Conclusions and Implications: The fast and slow PV pacemaker had different electrophysiological characteristics. I-to, I-K1, and I-f may regulate the beating rates of PV pacemaker cardiomyocytes.(J Cardiovasc Electrophysiol, Vol. 20, pp. 1039-1045).