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有研究表明白藜芦醇甙(polydatin)具有抗缺血性心律失常作用,但其电生理学机制尚未明了。本研究旨在应用细胞内记录和全细胞膜片钳方法,探讨白藜芦醇甙对大鼠心室乳头状肌动作电位的影响及其离子机制。结果显示:(1)白藜芦醇甙(50和100μmol/L)可剂量依赖性地缩短正常乳头状肌动作电位复极化50%时间(APD50)和90%时间(APD90)(P<0.01)。白藜芦醇甙对正常乳头状肌静息电位(resting potential,RP)、动作电位幅值(amplitude of action potential,APA)、超射值(overshoot,OS)和0期最大上升速度(Vmax)无影响(P>0.05)。(2)对部分去极化的乳头状肌,白藜芦醇甙(50μmol/L)不但缩短APD50和APD90,而且还降低动作电位OS、APA和Vmax(P<0.05)。(3)ATP敏感钾通道阻断剂格列本脲(10μmol/L)可部分阻断白藜芦醇甙(50μmol/L)的电生理效应。(4)一氧化氮合酶抑制剂L-NAME(1 mmol/L)对白藜芦醇甙的上述效应无影响。(5)白藜芦醇甙(25、50、75、100μmol/L)可浓度依赖性降低L-型钙电流。(6)白藜芦醇甙(50μmol/L)可增加ATP敏感钾电流。以上结果提示,白藜芦醇甙可浓度依赖性缩短正常乳头状肌动作电位复极化过程,抑制部分去极化乳头状肌动作电位,此作用与L-型钙通道阻断、ATP敏感钾通道开放有关。
Studies have shown that polydatin has anti-ischemic arrhythmia, but the electrophysiological mechanism is not yet clear. The aim of this study was to investigate the effect of polydatin on the action potential of ventricular papillary muscles in rats and its ionic mechanism using intracellular recording and whole-cell patch-clamp method. The results showed that: (1) Polydatin (50 and 100 μmol / L) could dose-dependently shorten the APD50 and APD90 of normal papillary muscles (P <0.01) ). The effects of polydatin on resting potential (RP), amplitude of action potential (APA), overshoot (OS) and maximal rate of rise of phase 0 (Vmax) No effect (P> 0.05). (2) For partially depolarized papillary muscles, polydatin (50 μmol / L) not only shortened APD50 and APD90, but also decreased the action potentials OS, APA and Vmax (P <0.05). (3) The ATP-sensitive potassium channel blocker glibenclamide (10 μmol / L) partially blocked the electrophysiological effects of polydatin (50 μmol / L). (4) L-NAME (1 mmol / L), a nitric oxide synthase inhibitor, had no effect on the above effects of polydatin. (5) Polydatin (25,50,75,100μmol / L) could decrease L-type calcium current in a concentration-dependent manner. (6) Polydatin (50μmol / L) increased the ATP-sensitive potassium current. The above results suggest that polydatin can shorten the process of normal papillary muscle action potentials repolarization in a concentration-dependent manner, and inhibit the partial depolarization of papillary muscles. This effect is related to the blockade of L-type calcium channel, ATP-sensitive potassium Channel open related.