PHILPOTT C W, COPELAND D E
J Cell Biol. 1963 Aug;18(2):389-404. doi: 10.1083/jcb.18.2.389.
Fundulus heteroclitus which can survive in a wide range of salinities, and F. similis and F. chrysotus which are usually restricted to salt water and fresh water environments, respectively. Gills were removed from F. heteroclitus which had been laboratory adapted to either sea water or pond water. For a comparison, gills were also removed from the marine F. similis and the fresh water F. chrysotus which had been adapted to their natural environments. Gill-filaments were fixed in Millonig's phosphate buffered (pH 7.4), 1 per cent osmium tetroxide and were embedded in Epon. Thin sections of filaments were stained with lead hydroxide. The cytoplasm of chloride cells of all three species of Fundulus is heavily populated with mitochondria and is filled with tubules of the agranular endoplasmic reticulum (ER). An orderly secretory cycle was indicated for chloride cells of salt water adapted F. heteroclitus and the marine F. similis. An amorphous material is observed in the agranular ER. Its density increases towards the apical end of the cell. In the apical cytoplasm, tubules of the agranular ER appear to converge and to discharge the amorphous material into an apical cavity. Except for the actual opening of the apical cavity, the distal end of salt water adapted chloride cells is characteristically shielded from the hypertonic environment by thin cytoplasmic flanges projecting from the neighboring epithelial cells. Chloride cells of the fresh water F. chrysotus resemble chloride cells of pond water adapted F. heteroclitus, in that these cells do not have apical cavities with the functional appearance of those in the sea water adapted forms. The distal end of fresh water adapted chloride cells is typically exposed to the free surface of the gill-filament. The possible function of the cell type is discussed.
通过比较三种鱼类鳃上皮中氯离子细胞的精细结构，研究了硬骨鱼渗透压调节的形态学基础：能在广泛盐度范围内生存的杂色底鳉，以及通常分别局限于咸水和淡水环境的相似底鳉和金眼底鳉。从实验室适应海水或池塘水的杂色底鳉中取出鳃。作为比较，还从适应其自然环境的海洋相似底鳉和淡水金眼底鳉中取出鳃。鳃丝固定在pH值为7.4的米隆尼氏磷酸盐缓冲液中，1%的四氧化锇中，并包埋在环氧树脂中。鳃丝的薄切片用氢氧化铅染色。所有三种底鳉的氯离子细胞的细胞质中都富含线粒体，并充满了无颗粒内质网（ER）的小管。适应海水的杂色底鳉和海洋相似底鳉的氯离子细胞显示出有序的分泌周期。在无颗粒内质网中观察到一种无定形物质。其密度向细胞顶端增加。在顶端细胞质中，无颗粒内质网的小管似乎汇聚并将无定形物质排入顶端腔。除了顶端腔的实际开口外，适应海水的氯离子细胞的远端通常由相邻上皮细胞伸出的薄细胞质凸缘与高渗环境隔开。淡水金眼底鳉的氯离子细胞类似于适应池塘水的杂色底鳉的氯离子细胞，因为这些细胞没有具有适应海水形式的功能性外观的顶端腔。适应淡水的氯离子细胞的远端通常暴露于鳃丝的自由表面。讨论了这种细胞类型的可能功能。
