Aminergic and cholinergic innervations of the spinal cord blood vessels of cats. A histochemical study.

The distribution patterns of aminergic and cholinergic nerve fibers in the feline spinal cord blood vessels were studied by means of amine histofluorescence and acetylcholinesterase (AChE) staining. These patterns were compared with those of the cerebral blood vessels. The anterior spinal artery had a dense network of aminergic and AChE-positive (probably cholinergic) nerve fibers. The posterior spinal vein, in contrast, exhibited only aminergic nerve fibers. Small intraparenchymal blood vessels in the spinal cord also had strongly fluorescent (probably peripheral) aminergic nerve fibers, as well as pial spinal blood vessels. This was a characteristic feature in the spinal cord. The distribution pattern and the density of these two sorts of nerve fibers in the anterior spinal artery varied widely with the individual segment of the spinal cord. The thoracic spinal cord had the lowest number of these nerve fibers of any part of the spinal cord. This fact may explain why the thoracic spinal cord is most susceptible to ischemic change.