Role of vasa vasorum in nourishment of the aortic wall

ment of the aortic z.uaZZ. Am. J. Physiol. 240 (Heart Circ. Physiol. 9): H781-H787, 1981.-Vasa vasorum are present in the middle and outer layers of media in the thoracic aorta of dogs and humans. To examine the role of vasa vasorum in nourishment of the aorta, we ligated four contiguous pairs of intercostal arteries in anesthetized dogs. These arteries are the source of vasa to the descending aorta but not the aortic arch. Blood flow through vasa vasorum was measured with micro-spheres. Acute intercostal ligation did not reduce conductance in the aortic arch but reduced conductance in the middle third of the descending aorta from 7 t 1 to 3 I~I 0.7 (SE) ml. min. 100 g- ’. mmHg- ’ (P < 0.05). After intercostal ligation, infusion of adenosine (5,umol = kg- ’ l min- ’ iv) increased conductance in the aortic arch 3- to 4-fold but did not increase conductance in the descending aorta. Six to ten days after intercostal ligation