[Effect of blockade and stimulation of adrenoreceptors on the pumping function of the heart in animals adapted and unadapted to physical loading].

Experiments with blockade of beta-adrenoceptors in rats revealed chronotropic effects of adrenaline and noradrenaline, as well as action of noradrenaline on systolic blood volume. The influence of adrenaline on systolic blood volume increases in that case, whereas combined blockade of both types of adrenoceptors sharply lowers it. In case of separate blockade of alpha-adrenoceptors, the action of adrenaline changes slightly. In physical exercise, adaptation of chronotropic and systolic effects of catecholamines are changed reciprocally. In condition of beta-adrenoceptor blockade and prior to it, the influence of adrenaline on systolic blood volume is much higher in adapted animals than in the control ones.