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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 investigate the effect of quercetin on calcium-activated potassium channel (KCa) in human mesenteric artery smooth muscle cells to investigate the mechanism of quercetin dilating blood vessels at the molecular level. METHODS: We selected 14 patients who had undergone elective abdominal surgery and had normal blood pressure. Small mesenteric artery branches were obtained. Single mesenteric artery smooth muscle cells were obtained by acute enzymatic digestion. Then single-channel patch-clamp technique was used to observe the Kpa channel open probability (NPo), current amplitude (Am), mean opening time (To), and mean closure time (Tc) of mesenteric artery smooth muscle cells with different concentrations of quercetin. Impact. RESULTS: Under the internal-outer configuration, the channel NPo was significantly increased with the increasing concentration of quercetin in the bath. When the quercetin concentration was 100 μmol/L, the NPO was 0.028 62± before the administration (ie, 0 μmol/L). 0.011 99 increased to 0.147 03±0.058 17 (P<0.01); channel Am and To did not change significantly (P>0.05); and channel Tc shortened significantly: from before treatment (477.650±376.650) ms to (112.643±114.365) Ms (P<0.01). CONCLUSION: Quercetin can directly activate KCa channels in human vascular smooth muscle cells to achieve hypotensive effect.