Integration between myogenic response and neurovegetative activity in the regulation of the coronary flow.

In the anaesthetized dog a 10 s increase in the coronary perfusion pressure was obtained by constriction of the descending thoracic aorta. At the release of the constriction, the pressure fell abruptly below the control and about 10 s later was followed by a transient myogenic reduction of the coronary vascular resistance. The reduction occurred to about the same extent in the animals with the intact vagi, after vagotomy and after vagotomy plus beta blockade, showing that changes in the basal vasomotor tone do not affect the amplitude of the myogenic vasodilation.