DISTRIBUTION OF NADPH-DIAPHORASE-POSITIVE NEURONS IN THE ENTERIC NERVOUS-SYSTEM OF THE HUMAN COLON

Recent investigations have demonstrated the colonization of NOS-immuno reactivity and NADPH-diaphorase staining in central and peripheral neu rons. The current study investigates the presence and distribution of NADPH-diaphorase-stained nerve cells and fibres in wholemount preparat ions of the enteric nervous system of the human colon. Numerous NADPH- diaphorase-stained nerve cell bodies were found in the plexus myenteri cus and in the plexus submucosus externus. In contrast, we found but v ery few NADPH-diaphorase-stained nerve cells in the plexus submucosus internus. The majority of the NADPH-diaphorase-stained nerve cells had morphological characteristics similar to those of the Dogiel type I n euron, i.e. possessing broad flat dendrites and one major axonal proje ction. NADPH-diaphorase-stained nerve fibres can be observed in all th ree ganglionic networks and in the aganglionic plexus of the circular muscle layer.