Abstract
The spinal cord, especially the thoracic and sacral lateral horn cells and their fiber connections of the dog were studied with the fluorescence method for catecholamine developed by FALCK and HILLARP. The thoracic and sacral rhizotomy, and the treatment with drugs that interfere with catecholamine metabolism, were also performed in order to clarify the possibility of catecholamine-biosynthesis in the preganglionic neurons.
The thoracic and sacral lateral horn cells are unable to produce or take up catecholamines. The thoracic preganglionic neurons are bilaterally innervated by monoaminergic nerve fibers originating from some supraspinal locus; the fibers descending mainly in the lateral funiculus. The sacral parasympathetic nuclei are also similarly innervated with the monoaminergic fibers. Several unmyelinated fluorescent fibers originating from supraspinal locus descend in the lateral funiculus, and appear in the anterior roots of the thoracic and sacral segments without any relays on the interneurons in the spinal cord.
