Preliminary immunohistochemical new findings in the myenteric plexus of patients with intestinal neuronal dysplasia type B.

In order to investigate the causes of abnormal peristalsis of the colon in intestinal neuronal dysplasia (IND), we studied the structure of the myenteric plexus of IND colon using silver-impregnation (Suzuki's method) as well as the innervation of both IND colons and normal colons using immunofluorescence technique with monoclonal antibodies to synaptic vesicles, and antisera to vasoactive intestinal polypeptide (VIP), substance P (SP), methionine-enkephalin (Met-Enk), and gastrin-releasing peptide (GRP). The following results were obtained. 1) In the IND colon, the number of identifiable myenteric ganglia was decreased. In a few cases of IND, irreversible neuron degeneration can be involved in the pathogenesis of IND. 2) In the IND colon, the distribution and fluorescence intensity of synaptic vesicles coincided with those of peptidergic nerve fibers. In the normal colon, synaptic vesicles were much more numerous in the circular muscle layers than in the longitudinal muscle layers, and the fluorescence intensity of those in the circular muscle layers was stronger than that of those in the longitudinal muscle layers. On the other hand, in IND colon, there were fewer synaptic vesicles in the circular muscle layers, and their fluorescence intensity was weak, while there were many synaptic vesicles in the longitudinal muscle layers, and their fluorescence intensity was strong. 3) Morphological abnormalities may exist in synaptic vesicles in the circular muscle layers of the IND colon. 4) Regarding the peptidergic nerve fibers, in the IND colon, innervation of circular muscle layers by Met-Enk-, GRP- and SP-immunoreactive fibers was reduced, and longitudinal muscles were more strongly innervated by immunoreactive fibers than those in the normal colon. 5) Disturbed innervation of non-adrenergic non-cholinergic excitatory nerves may cause the disturbance of muscle contractions in the IND colon. In addition, an imbalance of peptidergic and synaptic vesicle's innervations in both muscle layers may be related to the abnormal peristalsis of IND colon. Also, morphological abnormalities of synaptic vesicles may be concerned with its abnormal peristalsis.