高血压病患者肠系膜动脉平滑肌细胞钙激活钾通道研究

STUDY ON CALCIUM-ACTIVATED POTASSIUM CHANNEL OF MESENTERY ARTERY SMOOTH MUSCLE CELLS OF HYPERTENSION PATIENTS

目的:研究高血压病患者肠系膜动脉平滑肌细胞钙激活钾通道(KCa)的功能活动。方法:应用膜片钳制技术内面向外式单通道记录方法。结果:①人肠系膜动脉平滑肌细胞KCa开放具有电压依赖性。KCa通道电导在高血压组、正常组分别为191.4pS、197.7pS。胞内侧应用TEA可阻断通道。②增加浴液中Ca2+浓度(从0增至10-8、10-7、5×10-7、10-6mol/L),各组KCa开放概率(Po)均呈浓度依赖性增加,高血压组Po从0.016增至0.023、0.031、0.053、0.094,正常组Po从0.004增至0.023、0.041、0.072、0.184。通道平均开放时间延长,平均关闭时间缩短。③Ca2+浓度为0时,高血压组KCa开放概率明显高于正常组,在其它Ca2+浓度下高血压组KCa开放概率等于或低于正常组。结论:高血压病患者肠系膜动脉平滑肌细胞KCa的Ca2+敏感性较低,可能促进高血压的发生。

To study the functional activity of KCa on human mesenteric artery smooth muscle cells（SMC） from essential hypertension （EH） patients. Methods： Patch clamp technique with Inside-out mode was used for recording channel activity. Results： （1）KCa from human mesenteric artery SMC was voltage dependent. Single channel conductance was 191.4pS and 197.7pS in EH group and normal group respectively. The channel activity was blocked by TEA in cytoplastic side. （2）Withthe increasing of Ca^2＋ concentration in the bath solution（from 0 to 10^-8,10^-7,5 × 10^- 7, 10^-6mol/L）, the KCa channel open probability（Po） of two groups were increased, Po of EH group increased from 0.016 to 0.023, 0.031,0.053, 0.094, Po of normal group increased from 0.004 to 0.023, 0.041, 0.072, 0. 184. The mean open time lengthened and the mean close time shortened. （3）Po of KCa of EH group was higher than that of normal group when Ca^2＋ concentreation was 0, but it was equal with or lower than normal group at the other Ca^2＋ concentreations. Conclusion： KCa of mesenteric artery SMC from EH group has a lower Ca^2＋ sensitivity than that of nomal person. This might be an active factor for the onset of EH.