Homeostasis of gastric mucosa and effects of peptidergic nerve on mucus metabolism

1)组织化学结果表明，包括CGRP在内的神经肽免疫反应阳性物质分布于大鼠胃黏膜固有层和粘膜下层的神经纤维。虽然CGRP免疫反应神经纤维主要分布于粘膜下微血管，但在固有层中有一部分纤维与胃腺平行并靠近胃腺，其中一些接近胃表面上皮细胞。2)大鼠胃组织与[~3H]氨基葡萄糖孵育5h后，获得放射性标记的粘蛋白。在培养的胃粘膜中，CGRP刺激[~3H]氨基葡萄糖掺入粘蛋白中。3)详细研究各种坏死剂对胃粘膜损伤的修复过程对胃粘膜的动态平衡具有重要意义。为了阐明这一问题，我们制备了与存在于胃肠道粘膜特定区域和层的粘蛋白分子反应的单抗。用Wistar大鼠制作醋酸性胃溃疡模型。禁食24小时后，分别于酸刺激后20、30、50天处死动物，立即取胃。在冰醋酸诱导的胃损伤愈合过程中，一种被HCM31特异性染色的唾液酸粘蛋白在再生上皮细胞中有明显但短暂的表达。4)这些发现提示CGRP作用于胃体表面上皮细胞，并参与大鼠胃粘膜的维护。

In this study, we examined the maintenance of gastric mucosa and the role of peptidergic nerve on epithelium.1) Our histochemical findings indicate that immunoreactivity for neuropeptides including CGRP distributes in the nerve fibers of the lamina propria and submucosal layer of rat gastric mucosa. Although CGRP-immunoreactive nerve fibers mainly innervate the submucosal microvasculature, a certain part of these fibers is shown to run parallel and close to the gastric glands in the lamina propria, some of which approach the surface epithelial cells of the rat stomach.2) Radiolabeled mucin was obtained from the tissue of the rat stomachs incubated for 5 h with [3H]glucosamine. The incorporation of [3H]glucosamine into the mucin was stimulated by CGRP in the cultured corpus mucosa.3) Detailed research on the healing process of gastric mucosa from injury due to various necrotizing agents is important for homeostasis of gastric mucosa. To elucidate this issue, we prepared monoclonal antibodies reacting with mucin molecules present in the specific region and layer of the gastrointestinal mucosa. Acetic acid-induced gastric ulcers were prepared in Wistar rats. Following 24-h fasting, the animals were killed at 20, 30 and 50 days after acid insult and their stomachs were removed immediately. A notable but temporary expression of a kind of sialomucin specifically stained with HCM31 was observed in the regenerating epithelia during the healing stage of acetic acid-induced gastric damage.4) These findings suggest that CGRP acts on the corpus surface epithelial cells and participates in the maintenance of the rat gastric mucosa.