[Characteristics of load dependent relaxation of normal and hypertrophied myocardium in male and female rats].

Under monocrotaline treatment of rat right ventricle myocardium preparations significant changes in morphometric indices for male, but not for female preparations are adduced as compared to the control group. Peculiarities of adaptation of mechanocalcium uncoupling mechanism, one of important regulation mechanisms of rat myocardial contractility, were first revealed. Myocardial pressure overload results in the increase of time to peak force without alteration of characteristic time of isometric tension, relaxation for male rats under myocardial hypertrophy compared with control group rats. In addition, the decrease of the load dependent relaxation index in the male rats was obtained. Characteristics of myocardial contractility of female rats have not significant changes as compared to the control group.