Receptors for neurotransmitters in Auerbach's plexus of Hirschsprung's disease ; A comparison with animal models

本实验观察了先天性无神经节细胞增多症(AR)大鼠模型肠壁内皮素(EL)和P物质(SP)等神经递质受体的变化与大肠运动功能障碍的关系。我们用我们新开发的方法来分析受体的动力学；定量受体-成像系统包括三种实验技术，1)受体功能部位的体外放射配基结合技术，2)受体蛋白成熟部位的定量放射免疫组织化学技术，3)35S-cRNA探针的受体产生部位的原位杂交技术。结果发现，患者和AR大鼠结肠的主要主细胞(胆碱能神经元胞体)、结肠小肠节内均有ET_B受体的存在。用我们的方法证实了ET_B受体的选择性放射性配基^1^2^5IRL162O仅与1例先天性巨结肠症患者的结肠Aucrbach‘s丛结合。在这例患者中，我们使用我们的方法未能检测到P物质受体的代偿性增加。有趣的是，在另一例先天性巨结肠症患者中，未观察到^1^2^5I-1RL1620的异常结合，而P物质受体在神经丛中的表达非常低。因此，我们证实了ETB受体在先天性巨结肠症发病中的病理生理学意义，以及该病可能存在的另一个基因缺陷。调节P物质受体功能的因子可能有助于发现先天性巨结肠症的异质性。

We examined the changes in receptors of neurotransmitters such as endothelin (EL) and substance P in the intestinal wall related to the dysfunction of large-intestinal motility in Hirselisprung disease and its animal model of congenital aganglionosis (AR) rat, the rat with a mutant endothelin ET_B receptor. We used our newly-developed method for analyzing the receptor dynamics ; the quantitative receptor-imaging system with three experimental techniques, 1) in vitro radioligand-binding technique for functional sites of receptors, 2) quantilative radioimnunohistochernical technique for sites of receptor proteins maturation, and 3) in situ hybridization technique for production sites of receptors with 35S-cRNA probes. We found the existence of ET_B receptors in the main principal cell (cholinergic neuronal cell body) in Auerbach's plexus, and small enteroglia in the colon of patients and AR rats. With the use of our methods, we confirmed the finding that ^1^2^5IRL162O, a selective radioligand for the ET_B receptor, merely bound to the section of colon with Aucrbach's plexus isolated from a patient with Hirschsprung's disease. In this case of patient, we failed to detect a compensatory increase of substance P receptor, using our method. Interestingly, in another patient with Hirschsprung's disease no abnormal binding of ^1^2^5I-1RL1620 was observed, however, a very lower amount of the expression of substance P receptor in Anerbach's plexus. Thus, we confirmed the pathopliysiological significance of the ETB receptor in the onset of Hirschsprung disease, and the possible another gene-defect in this disease. A factor regulating substance P receptor function may shed some light on the discovery of the heterogeneity of Hirschsprung's disease.