Okumiya K, Matsubayashi K, Maeda T, Fujimiya M
Department of Medicine and Geriatrics, Kochi Medical School, Japan.
Peptides. 1996;17(2):225-32. doi: 10.1016/0196-9781(95)02138-8.
The present study provides morphological evidence to support the contention of exocrine secretion from duodenal gastrin-containing cells. The isolated vascularly perfused duodenal preparation with or without carbachol stimulation was used. At the end of perfusion, tissue was fixed and prepared for electron microscopic examination. For immunoelectron microscopic study for gastrin, postembedding immunogold reaction combined with preembedding DAB staining was used. In saline-treated controls, DAB reaction was restricted to the basal cytoplasm and immunogold labeling was concentrated over electron-dense cores of secretory granules packed at the basal cytoplasm. However, in carbachol-stimulated animals, immunogold labeling as well as DAB reactions were accumulated at the apical portion of the cytoplasm, suggesting that a high concentration of gastrin was involved in the apical cytoplasm. In carbachol-stimulated cells, aggregation of small vesicles was observed beneath the microvilli, and most of these vesicles had no cores but were similar in size to the basal secretory granules. Immunogold particles were diffusely scattered at the cytoplasm outside these vesicles. These findings suggest that the gastrin-like immunoreactivity was pooled at the matrix of apical cytoplasm in carbachol-stimulated cells, which might be derived from the secretory granules migrated from the basal cytoplasm into apical portion of the cells. In conclusion, the present study demonstrated the change in subcellular localization of gastrin-like immunoreactivity in intestinal gastrin cells after stimulation with carbachol. Aggregation of immunoreactivity at the apical portion of the cells suggests that gastrin may be released into the intestinal lumen.
本研究提供了形态学证据，以支持十二指肠含胃泌素细胞存在外分泌的论点。使用了有或没有卡巴胆碱刺激的离体血管灌注十二指肠标本。灌注结束时，将组织固定并准备进行电子显微镜检查。对于胃泌素的免疫电子显微镜研究，采用了包埋后免疫金反应结合包埋前DAB染色的方法。在生理盐水处理的对照组中，DAB反应局限于基底细胞质，免疫金标记集中在基底细胞质中堆积的分泌颗粒的电子致密核心上。然而，在卡巴胆碱刺激的动物中，免疫金标记以及DAB反应都聚集在细胞质的顶端部分，表明顶端细胞质中存在高浓度的胃泌素。在卡巴胆碱刺激的细胞中，在微绒毛下方观察到小泡聚集，这些小泡大多没有核心，但大小与基底分泌颗粒相似。免疫金颗粒分散在这些小泡外的细胞质中。这些发现表明，在卡巴胆碱刺激的细胞中，胃泌素样免疫反应性聚集在顶端细胞质的基质中，这可能源自从基底细胞质迁移到细胞顶端部分的分泌颗粒。总之，本研究证明了卡巴胆碱刺激后肠嗜铬样细胞中胃泌素样免疫反应性亚细胞定位的变化。细胞顶端部分免疫反应性的聚集表明胃泌素可能释放到肠腔中。
