Harmatina O. Investigation of expression and activity of nitric oxide synthases and heart function during ischemia/reperfusion of myocardium

Dissertation is devoted to investigation of NO-system role in the development of cardial dysfunction during ischemia/reperfusion of myocardium. In experiments on isolated perfused rat hearts under Langendorff preparation and homogenat of rat myocardium was investigation influence of NO on cardial function. In experiments was shown difference of expression and activity of NOS in tissues of ventricles myocardium during total ischemia and reperfusion of the heart. Expression and activity of iNOS in the right ventricle were higher then in the left one. Activation of NO-system by lipopolysacсharid (0,25 мг/кг) significantly increased expression and activity of iNOS in both ventricles and decreased of difference between of them and adduced to disturbances of cardiodynamics. Specific inhibition of iNOS activity by PBIT decreased expression and activity of iNOS in myocardium and increased myocardium contractilе function and decreased HR alterations. The similar effects on expression iNOS have been obtained inexperiments under the influence of cyclooxygenase modulators - indomethacin and prostaglandin E2. These results demonstrated that disturbances of cardiac function were connected with higher activation of iNOS during ischemia-reperfusion. One of the pathological mechanisms may be increased accumulation Ca2+ in cytosol of cardiomyocytes by nitric oxide and superoxide action during ischemia/reperfusion of myocardium.