人心房肌细胞钠通道的增龄性变化

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.

Sodium channel changes in human atrial cells isolated from various ages

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 ≥160 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 (I_(Na)) of right auricle myocytes. Results Both current density and time-dependent recovery of I_(Na). were similar in the cells from the 2 groups. Voltage-dependent inactivation of I_(Na) of myocytes in the aged atria was shifted to more positive voltages. Conclusion Current density of I_(Na) 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.