【摘要】 目的:观察薯蓣皂苷（Dio）对大鼠心肌收缩作用以及胞内Ca²⁺浓度的影响,并初步探讨其作用机制与Na⁺-Ca²⁺交换体（NCX）的关系。方法:采用Langendorff逆行主动脉灌流法对大鼠离体心脏进行灌流,利用压力感受器插管法测定左心室相关心功能参数,记录及其在应用NCX选择性抑制剂SEA0400情况下对左心室收缩压（LVSP）、左心室舒张末期压（LVEDP）、左心室内压最大上升/下降速率(±dp/dt_max)以及心率（HR）的影响;利用激光共聚焦显微观察薯蓣皂苷及SEA0400对大鼠心肌细胞H9c2细胞内Ca²⁺浓度的影响。结果:离体心脏灌流结果显示,1μmol/L Dio可显著增加LVSP,增加约19.7%（P<0.01）;增加左室内压最大上升速率(+dp/dt_max),增加约9.6%;激光共聚焦测定Ca²⁺荧光强度实验结果显示:1μmol/L Dio可使H9c2细胞中Ca²⁺相对荧光强度增加（P<0.01）;而在SEA0400存在的情况下,1μmol/L的Dio使细胞内Ca²⁺相对荧光强度变为（17.09±0.63）,给予Dio后差异有显著性（P<0.01）。在细胞液中无Ca²⁺或无Na⁺时,给予1μmol/L的Dio使Ca²⁺相对荧光强度减小,与给予1μmol/L的Dio差异有显著性（P<0.01）。结论:Dio可增加左心室收缩压和最大上升速率,表现正性肌力作用;Dio可使细胞内Ca²⁺浓度增加,其作用机制与增加Na⁺内流,促进NCX反向转运有关。更多还原

【Abstract】 Objective: To investigate the inotropic effects of dioscin（Dio）in rat isolated-heart and intracellular free calcium concentration in isolated rat ventricular myocytes and to explore its mechanism preliminarily. Methods: Left ventricle contractile function was measured using the Langendorff non-recirculating mode of isolated rat heart perfusion. Effects of dioscin and dioscin + SEA0400,sodium-calcium exchanger（ NCX） inhibitor,were investigated by measuring left ventricular systolic pressure（ LVSP） and left ventricular end diastolic pressure（ LVEDP）. Also,heart rate（ HR）,peak rate of rise / fall of left ventricular pressure( ± dp / dt_max) of isolated rat heart were calculated; Effects of dioscin and SEA0400 on intracellular free calcium concentration in rat H9c2 cells were measured by Fluo3-AM and then detected the fluorescence intensity with confocal microscopy. Results: With 1 μmol / L dioscin,LVSP was significantly increased by 19. 7%（ P < 0. 01） and dp / dt_maxwas increased by 9. 6%; With 1 μmol / L dioscin,the relative fluorescence intensity of intracellular free calcium concentrations were strong significantly（ P < 0. 01）. While in presence of SEA0400,the relative fluorescence intensity was changed to 17. 09 ± 0. 63（ P < 0. 01） by 1 μmol / L dioscin. With 1 μmol / L dioscin,the relative fluorescence intensity was weak（ P < 0. 01） without calcium or sodium in the extracellular fluid. Conclusion: Dioscin shows positive inotropic effect on isolated rat heart,enhancing the LVSP and + dp / dt_max; Dioscin increases the intracellular concentration of Ca²⁺ in the cardiac myocytes by increasing Na⁺influx and facilitating the reverse mode of the sodium-calcium exchanger.更多还原