Distribution of some neuropeptides in the porcine inferior mesenteric ganglion

: The occurrence and distribution of vasoactive intestinal polypeptide, substance P, and bombesin/gastrin-releasing peptide in neuronal cell bodies and nerve fibers of the porcine inferior mesenteric ganglion were studied with the indirect immunohistochemical technique. Of all substances studied only vasoactive intestinal polypeptide was found in principal ganglionic neurons. The presence of nerve fibers immunoreactive to vasoactive intestinal polypeptide, bombesin/gastrin-releasing peptide, and substance P was also found in the ganglion. There were differences in the pattern of distribution and density of the nerve fibers immunoreactive to the particular peptides. Fibers containing vasoactive intestinal polypeptide and bombesin/gastrin-releasing peptide were numerous, while fibers containing substance P were comparatively scarce. The present results revealed both similarities and specific differences in the occurrence and localisation of various neuropeptides in the porcine inferior mesenteric ganglion in comparison with that of other mammalian species.