THE RELATIONSHIP BETWEEN VESSEL WALL TENSION AND THE MAGNITUDE AND FREQUENCY OF OSCILLATION IN RAT AORTA

Aortic rings from adult normotensive rats display spontaneous rhythmic activity that is enhanced by vasoconstricting agents. Graded doses of norepinephrine as well as combinations of norepinephrine and vasodila tors produced levels of tension that were inversely related to the mag nitude of oscillation and directly related to the frequency. A similar result occurred with KCl stimulation. Oscillations were only slightly affected by removal of the endothelium. These results, when combined with other reported studies, suggest that the oscillations in rat aort a are a manifestation of feedback control that may involve the cyclic release of one or more agents affecting calcium channels.