Peptide-containing nerve in the rat stomach: an immunohistochemical study.

The distribution of peptide-containing nervous systems in the rat glandular stomach was studied immunohistochemically by use of the cryostat sections and whole mount preparations. A variety of peptide-containing nerve fibers made a dense network in the mucosa, submucosa, smooth muscle layers and intramural ganglia. Distribution density was the highest for nerve fibers containing vasoactive intestinal peptide (VIP) followed by calcitonin gene-related peptide, bombesin, and substance P. Peptide histidine isoleucine was detected in a few VIP-containing nerve fibers. Galanin, beta-endorphin and neuropeptide Y were also found in a variable density, mainly in the muscle layers. Somatostatin and gastrin were localized in the gut endocrine cells in contrast to their absence in the nervous systems. Truncal vagotomy did not affect the density nor distribution of various peptide-containing nerve fibers. In view of their distribution, the possible physiological roles of these peptides in the nervous systems on the regulation of the rat stomach were discussed.