运动对大鼠血管平滑肌大电导钾通道生物物理特性的影响

Effect of Different Intensities of Exercise on Biophysical Property of BK Channel

对大鼠进行不同强度的游泳训练以建立动物模型,应用膜片钳技术分析训练1～4周以及对照组的大鼠血管平滑肌细胞大电导钾通道(BK通道)的门控.实验结果显示,BK通道的开放概率在游泳训练第2、3周时明显升高,到第4周趋于稳定;游泳训练后,通道对膜电位、胞内钙离子的敏感性显著增加,通道的平均开放时间常数增大,关闭时间常数减小.实验结果还显示,由游泳训练导致的被动牵张并不改变通道的电导.BK通道在被动牵张力作用下生物物理特性的变化,可能有缓解由于游泳训练而导致血压升高的作用,进而使机体保持正常的生理状态.

We used exercise training rat as animal model, and investigated the effect of exercise training on the property of large-conductance Ca2＋ voltage-activated K＋ （BK） channels in VSMCs using patch clamp technique. The results showed that the open probability of channels increased significantly during the second and third week of exercise training, then became stable in the fourth week. After the exercise training, the sensitivity of channels to voltage and intracellular Ca2＋ was enhanced, and its mean opening time got longer while the mean closed time got shorter. Our results also showed that the exercise training had no effect on channel conductance. These changes in biophysical properties of BK channels after exercise training could be considered to prevent membrane depolarization and vasoconstriction.