Schneeberger E E, McCormack J M
Anat Rec. 1984 Nov;210(3):421-33. doi: 10.1002/ar.1092100303.
The structure of intercellular tight junctions of rat airway submucosal glands was examined by freeze fracture techniques and their permeability assessed by the use of colloidal lanthanum. The submucosal glands were organized into three distinct regions: a) serous tubules and b) mucous tubules lined, respectively, by serous and mucous cells, and c) ducts lined by cuboidal epithelial cells, containing few secretory granules, and some ciliated cells. The mean number of parallel fibrils constituting the tight junctions between serous cells was 3.6 +/- 0.4, which was significantly smaller than those between any of the other cell types. Colloidal lanthanum permeated the tight junctions between serous cells up to the level of the acinar lumen. There was a progressive increase in the mean number of parallel fibrils of tight junctions between mucous (5.1 +/- 0.6), ductal (5.4 +/- 0.5), and ciliated cells (8.5 +/- 0.7); none of these junctions was permeated by colloidal lanthanum. These results imply that tight junctions between serous cells are more permeable to small water-soluble solutes than those present in the more proximal portions of the gland. Gap junctions were observed between serous cells and between mucous cells, suggesting that these secretory cells may be electotronically and metabolically coupled.
采用冷冻断裂技术研究大鼠气道黏膜下腺细胞间紧密连接的结构，并用胶体镧评估其通透性。黏膜下腺分为三个不同区域：a）浆液小管；b）黏液小管，分别由浆液细胞和黏液细胞衬里；c）导管，由立方上皮细胞衬里，含少量分泌颗粒及一些纤毛细胞。构成浆液细胞间紧密连接的平行纤维平均数量为3.6±0.4，明显少于其他任何细胞类型之间的平行纤维数量。胶体镧可透过浆液细胞间的紧密连接直至腺泡腔水平。黏液细胞（5.1±0.6）、导管细胞（5.4±0.5）和纤毛细胞（8.5±0.7）间紧密连接的平行纤维平均数量逐渐增加；胶体镧均未透过这些连接。这些结果表明，浆液细胞间的紧密连接对小的水溶性溶质的通透性高于腺体近端部分细胞间的紧密连接。在浆液细胞之间以及黏液细胞之间观察到了缝隙连接，提示这些分泌细胞可能存在电偶联和代谢偶联。
