【摘要】 目的观察低浓度(1×10^-8mol·L^-1)哇巴因（OUA）对大鼠心肌细胞的收缩作用,并研究低浓度哇巴因发挥正性肌力作用有关的钠钾泵（NKA）信号转导通路。方法在急性分离的大鼠心室肌细胞上,利用全细胞膜片钳技术记录钠钾泵电流（Ip）,并观察低浓度哇巴因对Ip作用的影响。利用细胞动缘探测系统测定心肌细胞的长度及收缩力的大小。①观察并比较1×10^-81×10^-3mol·L^-1浓度哇巴因增强大鼠心室肌细胞收缩力的作用。②分别用信号转导抑制剂PP2(1μmol·L^-1)、NAC(100μmol·L^-1)及PD98059(50μmol·L^-1)与1×10^-8mol·L^-1哇巴因共同灌流,记录信号转导抑制剂对1×10^-8mol·L^-1哇巴因增强大鼠心室肌细胞收缩力的影响。结果 1×10^-81×10^-3mol·L^-1的哇巴因均能增加大鼠心室肌细胞收缩力（P<0.01）;1μmol·L^-1PP2+1×10^-8mol·L^-1哇巴因组与1×10^-8mol·L^-1哇巴因组相比心肌细胞收缩力减小（P<0.05）,100μmol·L^-1NAC+1×10^-8mol·L^-1哇巴因组与1×10^-8mol·L^-1哇巴因组相比心肌细胞收缩力也明显减小（P<0.01）;而50μmol·L^-1PD98059+1×10^-8mol·L^-1哇巴因与1×10^-8mol·L^-1哇巴因组相比信息及细胞收缩力没有显著性差异（P>0.05）。结论 1×10^-81×10^-3mol·L^-1的哇巴因均能增加大鼠心室肌细胞收缩力,且具有浓度依赖性。低浓度哇巴因的正性肌力作用与离子转运功能无关而与钠钾泵的信号转导功能有关,其中Src/ROS信号途径参与调节了1×10^-8mol·L^-1的哇巴因的正性肌力作用。更多还原

【Abstract】 OBJECTIVE To observe whether low concentration(1×10^-8 mol · L^-1) of ouabain（OUA） can increase the contractility in rat cardiocytes and investigate the Na/K pump signal transduction pathways related to positive inotropic action following the low concentration of OUA.METHODS On enzymatic isolation of rats ventricular myocytes,the Na⁺/K⁺ pump current（Ip） was by whole-cell patch-clamp,in order to observe the low concentration of OUA on Ip.The contraction of a single myocyte was assessed by a video-based motion edge-detection system.①To detect and compare the potentiations of 1×10^-8-1×10^-3 mol · L^-1 OUA on the contractility in rat cardiocytes.②The cardiocytes were pre-treated with PP2(1 μmol · L^-1),NAC(100 μmol · L^-1),PD98059(50μmol · L^-1) for 5 min,and the effects of the signals transduction inhibitors on the positive inotropic effect of 1×10^-8 mol · L^-1 OUA was recorded.RESULTS The 1×10^-8- 1×10^-3 mol · L^-1 OUA increased the contractility of rat cardiocytes（P <0.01）.Compared 1 μmol · L^-1 PP2 + 1×10^-8 mol · L^-1 OUA group with 1×10^-8 mol · L^-1 OUA group,the contraction amplitude decreased（P<0.05）,and compared 100 μmol · L^-1 NAC +1×10^-8 mol · L^-1 OUA group with 1 × 10^-8mol · L^-1 OUA group,the contraction amplitude also decreased（P <0.01）,no significant difference in contraction amplitudes between 50 μmol · L^-1 PD98059 + 1×10^-8 mol · L^-1 OUA group and 1 × 10^-8mol · L^-1 OUA group（P>0.05）.CONCLUSION The 1×10^-8-1 ×10^-3mol · L^-1OUA could increase the contraction amplitude of cardiocytes in rats in concentration-dependent manner.Positive inotropic effect of OUA in low concentration is related to Na/K pump signal transduction.Multiple signal pathways regulate the positive inotropic effect of1×10^-8mol · L^-1 of OUA,including the Src/ROS signal pathway.更多还原