Gotow T, Hashimoto P H
J Neurocytol. 1982 Jun;11(3):363-79. doi: 10.1007/BF01257983.
The permeability of intercellular junctions in specialized ependymal cells in the rat subcommissural organ (SCO) has been studied ultrastructurally by freeze-fracturing and tracer experiments with horseradish peroxidase (HRP). In addition to normal smooth membrane, areas which could be classified as a leaky tight junction are found within the ependymal junctional region. This consists of only one or two relatively continuous strands but with interruptions in the apical portion. Some strands are perpendicular to the apical membrane surface and often form hairpin-like bends in the basal portion of the junction. The junctional region also shows areas with no strands but only a rippled membrane structure which may be equivalent to very close appositions without fusion of adjacent ependymal cell membranes. The relative proportions of normal smooth membrane, strands and rippled structure in the junctional region is approximately 3:4:6 including two parts overlapping of the strands and rippled structure. Intraventricularly infused HRP passes through many junctions but is occasionally stopped, leaving unstained intercellular spaces of various lengths between membrane fusions of tight junctions. Even when it is stopped, the intercellular space below the junction is densely stained by the enzyme. Orthogonal arrays of intramembrane particles are found to be distributed on the basal and lateral cell membranes below the junctional region in the SCO ependyma.
通过冷冻断裂和辣根过氧化物酶（HRP）示踪实验，对大鼠连合下器官（SCO）中特化室管膜细胞间连接的通透性进行了超微结构研究。除了正常的光滑膜外，在室管膜连接区域内还发现了可归类为渗漏紧密连接的区域。这仅由一两条相对连续的链组成，但在顶端部分有中断。一些链垂直于顶端膜表面，并且在连接的基部经常形成发夹状弯曲。连接区域还显示出没有链但只有波纹状膜结构的区域，这可能相当于相邻室管膜细胞膜非常紧密贴靠但未融合的情况。连接区域中正常光滑膜、链和波纹状结构的相对比例约为3:4:6，其中链和波纹状结构有两部分重叠。脑室内注入的HRP穿过许多连接，但偶尔会受阻，在紧密连接的膜融合之间留下不同长度的未染色细胞间隙。即使它受阻，连接下方的细胞间隙也被该酶密集染色。发现膜内颗粒的正交阵列分布在SCO室管膜连接区域下方的基底和侧细胞膜上。
