机械牵拉对胚胎鸡心肌细胞大电导钾通道生物物理特性的影响

Effects of mechanical strain on the properties of large conductance K^+ channels cloned from chick ventricular myocytes

为了研究鸡心肌细胞BK通道对持续外加牵拉力的生物物理敏感性,从而了解心肌肥大和心力衰竭的发病机制,试验采用基底牵拉装置,对表达有克隆于胚胎鸡心肌细胞BK通道α亚基和共表达α、β亚基的胚胎鸡心肌细胞CHO-K1分别持续施加10%的拉伸应变24 h,应用单通道记录分析β亚基和钙离子在拉伸应变对BK通道生物物理特性影响中的作用。结果表明:拉伸应变作用于CHO-K1细胞后使通道的力敏感性明显增加,但牵拉对通道的钙离子依赖性影响不明显,而在此过程中β亚基并不起显著的作用。说明心脏在收缩、舒张时,心肌细胞由于遭受大的变形而产生力学作用,当这个力的作用超负荷时,会造成心肌肥大、心率不齐等一系列病变。

In order to study the chicken myocardial cell BK channel for constant plus pull biophysical sensitivity, so as to understand the patho- genesis of myocardial hypertrophy and heart failure. This study investigated the effects of mechanical strain on properties of BK channels cloned from chick ventricular myocytes. ClIO - K1 cells expressed α - subunits or co - expressed α and β suhunits of BK channels were exposed to mechanical strain of 10% for 24 hours. Application of single channel records, analysis beta snbunits and calcium ion in the tensile strain of bio- physical characteristics affect the role of BK channels. The results showed that the tensile strain in CHO - K1 cells after force sensitivity of channel significantly increased, but pull effect on the calcium ion dependence of the channel was not obvious, and in this process, the beta was not significant role. It was concluded that the contraction and relaxation of the heart, myocardial cells due to large deformation and mechanical action, when the role of the force was overwhelmed , occurred myocardial hypertrophy, irregular heartbeat and a series of pathological changes.