槲皮素对人肠系膜动脉平滑肌细胞钙激活钾通道的激活作用

Activation of quercetin to calcium-activated potassium channel in human mesenteric artery smooth muscle cell

目的:观察槲皮素对人肠系膜动脉平滑肌细胞钙激活钾通道(KCa)的影响,以探讨槲皮素在分子水平扩张血管的作用机制。方法:选取需择期行腹部手术并且血压正常的患者14例,取肠系膜动脉小分支,用急性酶消化法获得单个肠系膜动脉平滑肌细胞。然后应用单通道细胞膜片钳技术观察不同浓度槲皮素对肠系膜动脉平滑肌细胞KCa通道开放概率(NPo)、电流幅度值(Am)、平均开放时间(To)、平均关闭时间(Tc)等各指标的影响。结果:在内面向外式方式下,随着浴液中槲皮素浓度的增高,通道NPo明显增高:槲皮素浓度100μmol/L时,NPo由用药前(即0μmol/L)的0.028 62±0.011 99增高到0.147 03±0.058 17(P<0.01);通道Am、To变化不大(P>0.05);而通道Tc明显缩短:由用药前(477.650±376.650)ms缩短到(112.643±114.365)ms(P<0.01)。结论:槲皮素能直接激活人类血管平滑肌细胞KCa通道而实现降血压效应。

Objective：To explore the vasodilatation mechanism of quercetin at molecular level by investigating the effect of quercetin on calcium activated potassium channels （Kca） in human mesenteric artery smooth muscle （MASM） cells. Method,The mesenteric artery branches were excised from fourteen normotensive abdominal surgery patients with normal blood pression. Single MASM cell was obtained after digesting by enzyme. All experiments performed on single smooth muscle cell and recorded by patch clamp single channel recording technique. Open probability （Po）, current amplitude（Am）, mean open time （To） and mean close time（Tc） of Kca were observed at different quercertin concentration （0,12.5,25,50,100 μmol/L）. Result： In inside-out patch, quercertin enhanced human MASM Kca Po with the increasing of quercertin concentration in the bath solution： at quercertin from 0 to 100 μmol/L Po increased from 0. 028 62±0. 011 99 to 0. 147 03±0. 058 17 （quercertin 100 μmol/L）, n =10,P〈0.01; Tc was shortened from （477. 650±376. 650）ms to （112. 643±114. 365）ms （n= 10, P〈0.01） ; the change in Am or To was not significant（n = 10, P〉0.05）. Conclusion.-Quercertin can decrease blood pressure by activating directivelv Kca channels of human MASM.