Cx43基因敲除小鼠心室肌细胞动作电位及钾离子通道电流的变化

Connexin43 gene knockout mice lead to decrease of action potential duration and increase of the potassium current

目的研究缝隙连接蛋白43(Cx43)基因敲除对心室肌细胞钾离子通道电流的影响。方法选用2～3月大的Cx43基因敲除杂合子小鼠和相匹配的野生小鼠作对照,应用膜片钳全细胞记录技术记录小鼠心室肌细胞动作电位和钾离子流;电流钳状态下,记录心室肌细胞静息电位和动作电位;电压钳状态下,用钾离子通道外液灌流5min,依次记录内向整流性钾电流(IK1)和4-氨基吡啶不敏感的外向钾电流(ISS)。结果Cx43基因敲除小鼠心室心肌细胞动作电位复极到50%和90%的时间缩短,IK1离子流没有变化,而ISS离子流增加。结论Cx43基因敲除导致心室肌细胞动作电位时程缩短,ISS离子流增加。

Objective To investigate action potential and potassium current of ventficular myocardium on connexin 43 （ Cx43 ） gene knockout mice. Methods Mice with half level of Cx43 gene were used. Action potential were recorded using current-clamp technique, while inward rectifier potassium currents （ IK1 ） and 4-AP insensitive potassium currents （Iss） were recorded using volatage-clamp technique. Results Action potential duration at 50% and 90% repolarization were shorter and the Iss increased in Cx43^＋/- mouse compared with the Cx43^＋/＋ mouse. Conclusion Cx43 gene knockout lead to decrease of action potential duration and increase of the potassiun current.