虎杖甙对大鼠细动脉平滑肌细胞ATP敏感钾通道的影响

Effects of Polydatin on ATP Sensitive Potassium Channels of Arteriolar Smooth Muscle Cells

目的 :探讨中药虎杖提取物 -虎杖甙扩张休克动物细动脉、改善微循环灌流的作用机制。方法 :应用膜片钳技术的细胞贴附式观察虎杖甙对大鼠肠系膜细动脉平滑肌细胞 ATP敏感钾通道 ( KATP)的影响。结果 :细胞外液加入 0 .2 m mol/L虎杖甙后 ,通道电流幅度无明显改变 ,说明虎杖甙不影响 KATP通道电导 ;但加入虎杖甙后KATP通道动力学发生了明显变化 ,通道开放时间短成分 τ0 1 和长成分τ0 2 增大 ,通道开放时间 Tom延长 ,通道开放概率 Po提高 ,提示KATP通道激活。结论 :虎杖甙具有激活 KATP通道的作用 ,它可能通过使细动脉平滑肌超极化而扩张细动脉 ,从而改善休克动物微循环。

Objective: To study the mechanism of arteriolar dilation and microcirculation improvement induced by polydatin(PD) purified from a Chinese traditional herb medicine Polygonum Cuspidatum in shock Rats. Methods: Effects of PD on single K ATP channel currents of arteriolar smooth muscle cells(ASMCs) were studied with cell attached recording of patch clamp technique. Results: PD with a concentration of 0.2 mmol/L added to the bath solution had little effect on the current amplitude of K ATP channel. It suggested that PD did not change the channels conductance. However, PD changed the K ATP channel kinetics with τ o1 and τ o2 , T om and Open probability(P o) increased significantly. The results suggested that K ATP channels were activated. Conclusion: Polydatin has the effect of activating K ATP channels of ASMCs, which might contribute to arteriolar dilation and microcirculation improvement by hyperpolarizing arteriolar smooth muscle cells.