[Effect of adrenaline on the contractility of different portions of the myocardium of homeotherms].

The contractility of myocardial strips from the atrium and ventricle of rabbit heart had some differences in the parameters of single contraction, interval--tension relationship, and transitional process. These differences were eliminated by increasing the concentration of epinephrine in bath solution. Epinephrine changed the mode of time--force relation of contraction and induced appearance of extremum in all the parts of the heart. The linear relation between the force of atrium contraction and that of ventricle contraction (homochromity) during change of contraction frequency in normal solution, was shown. The homochromity of atrium and ventricle was broken by high epinphrine concentrations. The level of endogenous catecholamines which modulate the excitation--contraction relations, is believed to determine the differences in the physiological reactions of atrial and ventricular strips. The use of atrium of the heart as a transducer for management of artificial heart is proposed.