Noradrenergic nerves in human small intestine. Distribution and ultrastructure

Abstract

Noradrenergic nerves in human jejunum and distal ileum were identified at the light microscopic level by fluorescence histochemistry and at the ultrastructural level by 5-hydroxydopamine loading in vitro and by the chromaffin reaction. The myenteric and submucous ganglia contained dense arrays of varicose noradrenergic fibers; the muscularis externa, muscularis mucosae, intestinal glands, and villi were sparsely supplied. Enteric axon profiles that had taken up 5-hydroxydopamine contained variable proportions of flattened, small round, and pleomorphic large vesicles all containing electron-dense material. Chromaffin-reactive enteric axon profiles and some enteric profiles in conventionally f..