Localization of acetylcholine receptor in Hirschsprung's disease

点击翻译按钮获取中文摘要

It is not clearly defined why the aganglionic colon in Hirschsprung's disease remains contracted. Our electronmicroscopic study on acetylcholinesterase activity in Hirschsprung's disease revealed localization of the enzyme in the interspace between extrinsic nerve terminals and smooth muscle cells.Our research was aimed to clarify if the acetylcholine receptors exist on the smooth muscle cells to receive innervation of the extrinsic nerve fibers.Method: Localization of muscarinic acetylcholine receptors in the intestine of normal rats and Hirschsprung's rats was studied by autoradiography using [3H] quinuclidinyl benzilate.Results: Silver grains representing acetylcholine receptors were shown to distribute diffusely in the mucosa and submucosa, and linearly on the surface of muscular layers in normal rats. The grains were not recognized in the atropine-treated rats, indicating specificity of the grains to muscarinic acetylcholine receptors. Muscarinic acetycholine receptors were demonstrated also in the aganglionic colon of Hirschsprung's rats. The density of silver grains in the aganglionic colon did not differ much from that in the normal colon.Conclusions: Muscarinic acetylcholine receptors were present in the aganglionic colon of Hirschsprung's rat as in the normal rat colon. This finding indicates that smooth muscles of the aganglionic colon of Hirschsprung's disease may be directly innervated by the proliferated extrinsic nerves.