Neurotensin-containing neurons in the canine enteric innervation.

The intrinsic innervation of the gastrointestinal tract has been demonstrated to contain numerous peptidergic neurons. Neurotensin, originally isolated from bovine hypothalamus, has been localized in intestinal epithelial endocrine cells but not convincingly in the enteric innervation. The present study demonstrates the presence of neurotensin-immunoreactive neurons and nerve fibers in the canine submucous and myenteric ganglia. The peptide was characterized as neurotensin 1-13 by high pressure liquid chromatography and there was a mean concentration of 18.4 +/- 3.9 pmol (+/- S.E.M., n = 3) per g wet weight of submucosal extract. These neurons were a separate population from the vasoactive intestinal peptide- and somatostatin-immunoreactive cell bodies. These results demonstrate that neurotensin is present in significant amounts in the canine submucous plexus.