运动抑制高血压血管平滑肌细胞MaxiK通道电学重构

Exercise Inhibits Maxi K Channels Remolding of Vascular Smooth Muscle Cell in Rats with Hypertension

目的:研究有氧运动对自发性高血压大鼠(SHR)血管平滑肌细胞(VSMC)大电导钙激活钾通道(MaxiK)电生理特性的影响。方法:选用3月龄雄性SHR(n=24)与同龄雄性WKY大鼠(n=12),将SHR随机分为高血压安静组(SHR,n=12)和高血压运动组(SHR-EX,n=12),运动组进行8周的有氧运动。在全细胞膜片钳技术记录VSMC钾电流以及MaxiK电流;在内面向外模式下观察MaxiK门控特性。结果:1)SHR-EX收缩压和舒张压显著低于SHR;2)SHR组MaxiK电流密度显著高于WKY组,SHR-EX组MaxiK电流密度显著低于SHR组;3)SHR组MaxiK通道标准化开放概率(Po)、通道平均开放时间(To)、钙敏感性均显著高于WKY组,通道平均关闭时间(Tc)显著低于WKY;SHR-EX组MaxiK的标准化Po、To和钙敏感性均显著低于SHR组,Tc显著高于SHR组。结论:长期有氧运动抑制由高血压诱导VSMC的MaxiK通道电学重构。

Objective： The purpose of this study was to investigate the effects of aerobic exercise on electrophsiology properties of the large-conductance Ca2 ＋-activated K＋（ MaxiK） channels in vascular smooth muscle cells（ VSMC） of spontaneously hypertensive rats（ SHR）. Methods： Three-month old male SHRs（ n = 24） were randomly assigned to a sedentary control group（ SHR,n = 12） and an exercise training group（ SHR-EX,n = 12）.Male Wistar-Kyoto rats（ WKY,n = 12） with the same age were used as normotensive control group. Rats of SHREX group participated in 8 weeks exercise. The potassium and MaxiK currents of VSMC were recorded by patch clamp,and the characteristics of MaxiK gating were observed in the inside-out model. Result： 1） The basal systolic blood pressure and diastolic blood pressure were higher in SHR than in SHR-EX; 2） The current density of MaxiK channel in SHR was higher than in WKY,but WKY＇s was higher than those in SHR-EX＇s; 3） NPo,the mean open time（ To） and calcium sensitivity in SHR were higher than those in WKY. The mean close time（ Tc）was lower compared with WKY. NPo,To and calcium sensitivity of SHR-EX after exercise training significantly decreased compared with SHR. Tc of SHR-EX was significantly higher than that of SHR. Conclusion： Regular aerobic exercise can inhibit VSMC＇s MaxiK channels remolding induced by hypertension.