Fujisawa H, Morioka H, Watanabe K, Nakamura H
J Cell Sci. 1976 Dec;22(3):585-96. doi: 10.1242/jcs.22.3.585.
Ultrastructural studies of thin-sectioned and freeze-cleaved materials were performed on developing retinal tissues of 3- to 9-day-old chick embryos to clarify the junctional structures between neural retinal cells and between neural retinal cells and cells of the pigmented epithelium. Frequency, size and position of gap junctions in developing neural retina are different at each stage of development. In 3-day-old embryos, some cells adhere to each other by gap junctions immediately below the outer limiting membrane of neural retinae. The size and number of gap junctions increase remarkably during 5-6 days of incubation. In this period of development, well developed gap junctions consisting of subcompartments of intramembrane particles are found between cell surfaces at both the outer limiting membrane region and the deeper portion of the neural retina. Gap junctions disappear thereafter, and at 7-5 days of incubation, small gap junctions are predominant between cell surfaces at the outer limiting membrane region, while the frequency of gap junctions in the deeper portion is very low. At 9 days of incubation, gap junctions are rarely found. Typical gap junctions are always found between neural retinal cells and those of the pigmented epithelium in embryos up to 7-5 days of incubation. Tight junctions are not found in the neural retina or between neural retina and pigmented epithelium throughout the stages examined.
对3至9日龄鸡胚发育中的视网膜组织进行了超薄切片和冷冻蚀刻材料的超微结构研究，以阐明神经视网膜细胞之间以及神经视网膜细胞与色素上皮细胞之间的连接结构。发育中的神经视网膜中缝隙连接的频率、大小和位置在发育的每个阶段都有所不同。在3日龄胚胎中，一些细胞通过神经视网膜外限制膜下方紧邻的缝隙连接相互粘附。在孵化5至6天期间，缝隙连接的大小和数量显著增加。在这个发育阶段，在神经视网膜外限制膜区域和较深部分的细胞表面之间发现了由膜内颗粒亚区组成的发育良好的缝隙连接。此后缝隙连接消失，在孵化7至5天，外限制膜区域细胞表面之间以小缝隙连接为主，而较深部分缝隙连接的频率非常低。在孵化9天时，很少发现缝隙连接。在孵化至7至5天的胚胎中，神经视网膜细胞与色素上皮细胞之间总是能发现典型的缝隙连接。在所检查的整个阶段，在神经视网膜或神经视网膜与色素上皮之间均未发现紧密连接。
