Galanin-immunoreactive nerve terminals innervating the striated muscle fibers of the rat esophagus.

Galanin (GAL) immunohistochemistry combined with acetylcholinesterase (AChE) histochemistry was applied to demonstrate the innervation of the rat esophageal muscle coats. GAL immunoreactivity was found in a number of nerve cell bodies in the myenteric ganglia and in numerous varicose and non-varicose nerve fibers in the myenteric plexus and around blood vessels. Many GAL-positive varicose fibers ran in the internodal strands and along the striated muscle fibers. They often ramified and terminated on the muscle fibers to form arborizing structures, which were most abundant in the thoracic portion of the esophagus. Such GAL-positive terminals were localized in most (87.7%) of AChE-reactive motor endplates on the esophageal striated muscles. Left supranodose vagotomy caused a significant decrease of the GAL-arborizing terminals on the striated muscles of the esophagus. This suggests that they are terminals of efferent fibers in the vagus nerve.