Differrent changes of cardio- and hemodynamics following electrical stimulation of the right and left vagus nerves

In acute experiments on the anesthetized mongrel cats the changes of the right atrial pressure, superior and inferior vena cava flow and venous return were investigated following electrical simulation of the right and left vagus nerves in intact animals and after vagotomy. In intact animals stimulation of both nerves vagus caused the equal decreasing of heart rate, however, right atrial pressure increased more, if right vagus nerve were stimulated comparing with left vagus nerve stimulation. Right ventricular myocardial contractility, superior and inferior vena cava flow and venous return in the first case also decreased more in the first case. Vagotomy caused different (increasing and decreasing) changes of the right atrial pressure, increasing of right ventricular myocardial contractility and insignificant changes of the venous return. Electrical stimulation of the right and left vagus nerves after vagotomy caused equal negative chrono- and inotropic cardiac effects and decreasing of superior and inferior vena cava flow and venous return. However, even in these conditions right atrial pressure increased more, if right vagus nerve were stimulated comparing with left vagus nerve stimulation. Thus we have concluded, that character of the changes and values of the shits of the right atrial pressure following cardiac parasympathetic nerves stimulations have no linear dependence with venous return and they are determined in the case of equal changes of the venous return by the changes of the intracardiac hemodynamics.