The cholinergic innervation of the aorta

The cholinergic innervation of the aorta has been studied in some mammalian species. Cholinergic nerve fibers (CNF) are organized in the aorta of the rabbit, kid, lamb, and guinea pig in 2 plexuses. The plexuses of CNF consist of a superficial plexus localized in the adventitial layer and a deep one localized in the adventitial-medial transitional zone. Some CNF reach the outer layers of the media. In the aorta of the dog, mouse and rat CNF are organized in a single plexus localized in the adventitial layer. This nerve plexus is formed of CNF that for the most part are distributed to the vasa vasorum. The chemical sympathectomy don't alters the pattern of the cholinergic innervation of the aorta, indicating that stained CNF are parasympathetic in nature. The meaning of a cholinergic innervation of the aortic wall is discussed.