人动脉平滑肌钙激活钾通道与遗传因素的关系探讨

目的探讨高血压病(Essentialhypertension ,EH)患者及正常血压者肠系膜动脉平滑肌钙激活钾通道(Ca2+activated K+ channel ,Kca)的功能活动及其与遗传因素的相关性.方法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(Mesentericarterial smooth muscle,MASM)细胞的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.结果内面向外式膜片下,Nf组、Ef组MASM细胞Kca的Po、To、Tc与Nn组和En组比较,无显著性差异;细胞贴附式膜片下,当胞外Ca2+浓度≥1.8×10-3mmol/L时,Nf组和Ef组的MASM细胞Kca的Po分别低于Nn组,En组,To缩短和Tc延长.结论人MASM细胞Kca对胞内Ca2+的敏感性与遗传因素无关;人MASM细胞Kca对胞外Ca2+的敏感性降低与遗传因素有关,Kca对胞外Ca2+的敏感性降低可能是EH的发生机制之一.

ASSOCIATION OF Ca2+ ACTIVATED K+ CHANNEL IN HUMAN ARTERIES WITH GENETIC FACTOR

Objective:To investigate the association of Ca2+ activated K+ channel(Kca)in the mesenteric artery smooth muscle cells of essential hypertensive and normotensive with genetic factor.Methods:The standard patch clamp technique was used to record the single Kca channel current in inside-out and cell-attached patch clamp.Results:In inside-out patch, there was no significant difference in Po, To, Tc of Kca in EH with familial history(Ef) and EH without familial history (En); the same results were found in normotensive without familial history (Nn) and normotensive with familial history(Ns).In cell-attached patch, the extracellular Ca2+concentration was≥1.8×10-3 mmol/L, Po were significantly lower in Es and Nf groups than in the control individually, with To decreasing and Tc increasing.Conclusions:The sensitivity of Kca to intracellular Ca2+ was not associated with genetic factor. The decreased sensitivity to extracellular Ca2+ of Kca was associated with genetic factor, which may play a role in the pathogenesis of EH.