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 th e rat esophageal muscle coats. GAL immunoreactivity was found in a num ber of nerve cell bodies in the myenteric ganglia and in numerous vari cose 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 mot or endplates on the esophageal striated muscles. Left supranodose vago tomy caused a significant decrease of the GAL-arborizing terminals on the striated muscles of the esophagus. This suggests that they are ter minals of efferent fibers in the vagus nerve.