Résumé
Objective:To study the neuromuscular junction of the colon in patients with Hirschsprung’s disease by immunohistochemical methods.Methods:The distribution of the neuromuscular junction in the muscle layers of bowel from 10 normal controls and 20 Hirschsprung’s disease patients was studied by synaptophysin immunohistochemistry.Antimouse synaptophysin serum was used for visualization of neuromuscular junction.Results:In the colon of the control cases,synaptophysin-immunoreactivity was widely distributed in the circular muscle layer.In the dilated colon with Hirschsprung’s disease cases,synaptophysin-immunoreactivity was moderately distributed within normal ganglion cell and scarcely in constricted segment within degenerated ganglion cell.In contrast to the high degree of synaptophysin-immunoreactivity in the controls and dilated colon,the synaptophysin-immunoreactivity in the constricted segment were nil in the circular muscle layer.Conclutions:Dense synaptophysin-immunoreactivity nerve endings were prominent in the circular muscle layer in the control and there was almost no synaptophysin imm-unoreactivity activity in the circular muscle layer in the constricted segment.The circular muscle layer from the constricted segment is confirmed to be a region with poor innervation including extrinsic and intrinsic nerve. Based on the Cannon’s Law of Denervation,the muscles that are supplied by these nerves shorten and tighten,resulting in muscle spasm and stiffness.The constricted segment which was denervated,is incapable of transmitting normal propulsive peristaltic waves and therefore acts as a physiologic obstruction.