Substance P-like immunoreactive innervation of the human colon and coeliac, superior mesenteric and inferior mesenteric ganglia.

The localization of substance P is studied in the human prevertebral sympathetic ganglia and descending colon by the indirect immunofluorescence technique. Strongly immunoreactive axons reach the coeliac, superior mesenteric and inferior mesenteric ganglia. The sympathetic postganglionic neurones are surrounded by a meshwork of positive beaded fibers and terminals. Varicose nerve fibers are variously distributed in all nonepithelial layers of the colon. A close network of fibers and terminal surrounds the ganglionic cells in the mienteric and submucous plexuses. Substance P-like immunoreactive perikarya are present in these structures.