高血压病患者动脉平滑肌细胞钙激活钾通道变化及意义

目的　研究高血压病 (essential hypertension,EH )患者肠系膜动脉平滑肌 (mesenteric arterial sm oothmuscle,MASM)细胞钙激活钾通道 (Ca2 + activated K+ channel,KCa)改变及意义。方法　利用膜片钳单通道记录技术记录胞内和胞外 Ca2 +对无 EH家族史的正常血压者 (Nn 组 ) ,有 EH家族史的正常血压者 (Nf组 ) ,无 EH家族史的 EH患者 (En 组 ) ,有 EH家族史的 EH患者 (Ef组 )肠系膜动脉平滑肌 (MASM)细胞 KCa开放概率 (Po) ,平均开放时间 (To) ,平均关闭时间 (Tc)及电流幅值 (Am)的影响。结果　 (1)人动脉平滑肌 KCa开放具有明显的电压和 Ca2 +依赖性 ,其电导值大。 (2 )胞内 Ca2 + 浓度≥ 5× 10 - 7m ol/ L时 ,En 组、Ef 组 MASM细胞 KCa的 Po 分别低于 Nn 组、Nf组 ,To 缩短。(3)胞外 Ca2 +浓度≥ 1.8× 10 - 3m ol/ L 时 ,En 组、Ef 组 MASM细胞 KCa的 Po 分别高于 Nn 组、Nf组 ,To延长 ,Tc缩短。结论　 (1) EH患者 MASM细胞 KCa对胞内 Ca2 + 敏感性降低 ,这可能是促进高血压发生的机制之一。(2 ) EH患者 MASM细胞对胞外 Ca2 +敏感性增加 ,可能与胞外 Ca2 +内流增加导致胞内 Ca2 +增加有关

Changes and significance of Kca in arteries of essential hypertension

Objective To investigate the changes and Significance of Ca 2+ activated K + channel(K Ca) in mesenteric arterial smooth muscle(MASM) cells of essential hypertension. Methods The standard patch clamp technique was used to record the single K Ca channel current in inside-out and cell-attached patch clamp. Results (1) K Ca in MASM cells of human has significant voltage and Ca 2+ dependence, the conductance is high.(2)when intracellular Ca 2+ concentration was 5×10 -7, P o in E n and E f group was lower than that in control groups, with T c decreasing. (3) When extracellular Ca 2+ concentration was 1.8×10 -3, P o in E n and E f groups was higher than that in control groups, with T o increasing and T c decreasing. Conclusion The sensitivity to intracellular Ca 2+ of K Ca in MASM cells of EH decreased, which may play a role in etiopathology of EH. The sensitivity to extracellular Ca 2+ of K Ca in MASM cells of EH increased, which may be caused by the increased extracellular Ca 2+ influx.