[Interaction of inotropic effects on acetylcholine, adrenaline and increase of atrium stimulation frequency in rats adapted and non-adapted to physical exercise].

It is shown in experiments carried out on the isolated strips of the left and right atria of the rat that adrenaline decreases the inotropic effect of acetylcholine while interatrial differences of chrono-inotropy are elevated by acetylcholine and adrenaline. Training of animals changes interaction of regulatory effects in such a way that an increase of the negative chrono-inotropy is compensated and efficiency of the cardiac muscle regulation grows.