Study on the Mechanism of Enhanced Contractility of Ventricular Myocytes in Rats with Treatment Concentration of Ouabain

ZHOU Xiaohui; CAI Yue; GUO Shanshan; WANG Shumei; WANG Na; ZHANG Bo; WU Qing-hua; WANG Lingjiao

doi:10.3969/j.issn.1002-3429.2023.09.029

Abstract：Objective To investigate the effect of treatment concentration(10-8 mol/L)of Ouabain on contractile function of acutely isolated ventricular myocytes of rats and to study whether the signal transduction pathway activated by sodi-um and potassium pump is involved in the cardiac strengthening effect of Ouabain.Methods Ventricular cardiomyocytes of rats were acutely isolated by enzymolysis and supplemented with calcium.The systolic function of single rat cardiomyocytes were detected by visual single-cell moving edge detection system.The effect of 10-9-10-4 mol/L Ouabain on contractility of acutely isolated rat cardiomyocytes was observed.10-8 mol/L Ouabain was co-irrigated with 1 μmol/L PP2,100 μmol/L NAC,1 μmol/L U73122 and1 μmol/L Xestospongin C,and50 μmol/L PD98059,respectively.The effect of 5 kinds of sig-nal transduction pathway inhibitors on cardiotonic effect of 10-8 mol/L Ouabain was observed and recorded.Results The contractility of acutely isolated ventricular myocytes of rats was enhanced by 10-9～10-4 mol/L Ouabain(P＜0.01)in a concentration-dependent manner.1 μmol/L PP2,100 μmol/L NAC,1 μmol/L U73122 and 1 μmol/L Xestospongin C could partly inhibit the cardiotonic effect of 10-8 mol/L Ouabain(P＜0.05,P＜0.01).However,there was no significant differ-ence in the contraction amplitude of ventricular myocytes between 50 μmol/L PD98059 + 10-8 mol/L Ouabain and 10-8 mol/L Ouabain(P＞0.05).Conclusion 10-9 to10-4 mol/L Ouabain can increase the contractility of acutely isolated ventricular myocytes of rats.The cardiotropic effect of 10-8 mol/L Ouabain is most likely related to the Src/EGFR/Ras/ROS signal transduction pathway and the Src/EGFR/PLC/PIP2/IP3 signal transduction pathway activated by the sodium potassium pump.