人心房肌细胞钠通道的增龄性变化

Sodium channel changes in human atrial cells isolated from various ages

目的通过观察人心房肌细胞钠通道的增龄性变化，探讨心房颤动（房颤）发病率随年龄增加的原因。方法23例接受换瓣手术的患者按年龄分为成年组和老年组，所有患者均为正常窦性心律，采用全细胞膜片钳技术记录右心耳细胞的钠电流。结果两组的钠电流密度和时间依赖性恢复动力学差异均无统计学意义，但老年组电压依赖性失活曲线向更正的方向偏移。结论增龄对钠通道电流和恢复动力学无影响，老年组患者房颤发病率增高可能与钠通道无关。

Objective To investigate if the increased incidence of atrial fibrillation with age was associated with changes of Na^＋ channel in atrial myocytes. Methods Twenty-three patients underwent valve replacement operations were divided into adult [ 〈 60 years, n = 15, 9 males, mean age（42. 1 ±7.1 ） years ] and aged group [ ≥60 years, n = 8, 5 males, mean age （ 63. 3 ±3.1 ） years ]. All patients were in normal sinus rhythm. Whole cell patch clamp techniques were used to record the Na^＋ currents （INa） of right auricle myocytes. Results Both current density and time-dependent recovery of INa were similar in the cells from the 2 groups. Voltage-dependent inactivation of INa of myocytes in the aged atria was shifted to more positive voltages. Conclusion Current density of INa was similar between the 2 age groups, and Na ^＋ channel might not be an important determinant for the increased incidence of atrial fibrillation in aged patients.