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目的 观察广枣总黄酮对大鼠心室肌细胞L 型钙通道电流 (ICa)和瞬时外向钾通道电流 (Ito)以及对心肌细胞内游离钙浓度 ([Ca2 + ]i)的影响 ,探讨其抗心律失常作用机制。方法 全细胞膜片钳记录大鼠心室肌细胞ICa、Ito,激光共聚焦显微镜观察细胞 [Ca2 + ]i 的变化。结果 在钳制电压- 4 0mV ,实验电压 - 4 0～ +5 0mV时 ,广枣总黄酮 10 0mg·L-1对心室肌细胞ICa无显著影响 ;在钳制电压 - 6 0mV ,实验电压 - 4 0～ +5 0mV时显著抑制瞬时外向钾通道Ito(P <0 0 5 ) ;而激光共聚焦显微镜结果显示广枣总黄酮在 5 0、10 0、2 0 0mg·L-1却降低缺氧复氧心肌细胞收缩期和静息期[Ca2 + ]i 的浓度。结论 广枣总黄酮对心肌细胞ICa无显著影响 ,可显著抑制瞬时外向钾通道Ito,并可明显降低心肌细胞收缩期和静息期细胞 [Ca2 + ]i 浓度。这可能是其抗心律失常和保护缺血心肌的主要作用机制。
Objective To observe the effects of total flavonoids from Choerospondias axillaris on L-type calcium channel current (ICa), transient outward potassium channel current (Ito), and intracellular free calcium concentration ([Ca2 + ]i) in rat ventricular myocytes. Arrhythmia mechanism of action. Methods Ica and Ito of rat ventricular myocytes were recorded by whole-cell patch clamp. The changes of [Ca2 + ]i were observed by confocal laser scanning microscope. Results When the clamping voltage was -40 mV and the experimental voltage was between -40 and +50 mV, the total flavonoids of Guangzao 100 mg·L-1 had no significant effect on ICa in ventricular myocytes; the clamp voltage was -60 mV, and the experimental voltage was -40. Significant inhibition of transient outward potassium channel Ito was observed at +5 mV (P < 0.05), whereas laser confocal microscopy showed that total flavonoids of H. jujuba were decreased at 50, 100, and 200 mg L -1 but decreased by hypoxia. The systolic and resting [Ca2+]i concentrations of oxygenated myocardial cells. Conclusion The total flavonoids of Fructus Choerospondiatis had no significant effect on the ICa of cardiomyocytes, which could significantly inhibit transient outward potassium channel Ito, and significantly reduced the [Ca2 + ]i concentration in systolic and resting cells of cardiomyocytes. This may be its main anti-arrhythmic and protective mechanism of ischemic myocardium.