论文部分内容阅读
目的 :记录并研究急性分离小鼠心肌细胞容积敏感性氯通道电流的电生理学特征。方法 :采用全细胞膜片钳记录方法 ,记录急性分离的小鼠心肌细胞暴露于低渗溶液时 ,细胞体积增大后 ,出现的容积敏感性氯通道电流(volume_sensitivechloridechannelcurrent,ICl,Vol)。结果 :小鼠心肌细胞容积敏感性氯通道电流以外向电流占优势 ,在去极化正电压时有时间依赖性失活 ,电流_电压曲线显示其反转电位 [(_34.5± 0 .8)mV]接近氯离子平衡电位的理论值 (ECl=_38.6mV) ,且反转电位随细胞外氯离子浓度的改变而改变 ,Nerst方程常数为 4 3.9。电流的激活依赖于细胞内ATP。该通道的阴离子选择性为I_>Br_>Cl_,相对通透比为 2 .32∶1 .2 8∶1。结论 :小鼠心肌细胞具有明显的容积敏感性氯通道电流 ,且该电流具有外向整流性及时间依赖性失活特性
OBJECTIVE: To record and study the electrophysiological characteristics of cardiomyocyte volume-sensitive chloride channel currents in acutely isolated mice. Methods: Whole-cell patch-clamp recording was used to record volume-sensitive chloride channel current (ICl, Vol) after the acutely isolated mouse cardiomyocytes were exposed to hypotonic solution. Results: Myocardial cell volume-sensitive chloride channel current was dominated by outward current and deactivated in a time-dependent manner at depolarization positive voltage, with a current-voltage curve showing its reversal potential [(-34.5 ± 0.8 ) mV] is close to the theoretical value of chloride equilibrium potential (ECl = _38.6 mV), and the reversal potential changes with changes in extracellular chloride concentration, with a Nerst equation constant of 3.9. Current activation depends on intracellular ATP. The anion selectivity of this channel is I_> Br_> Cl_ and the relative permeability ratio is 2.32: 1 .2 8:1. CONCLUSION: The mouse cardiomyocytes have a volume-sensitive chloride channel current with outward rectification and time-dependent inactivation