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..