OCCLUDING JUNCTIONS IN CULTURED EPITHELIAL MONOLAYERS
OCCLUDING JUNCTIONS IN CULTURED EPITHELIAL MONOLAYERS
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DOI：
10.1152/ajpcell.1981.240.3.c96
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发表时间：
1981-01-01
影响因子：
--
通讯作者：
MARTINEZPALOMO, A
中科院分区：
文献类型：
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作者：
CEREIJIDO, M;MEZA, I;MARTINEZPALOMO, A
当[犬肾] MDCK细胞在单层培养时，它们合成、组装和密封限制细胞旁途径的闭塞连接。这些过程可能会受到蛋白质合成抑制剂的损害，但不会受到RNA合成抑制剂的损害。一旦建立，闭塞连接赋予单层80-600 Ω的总电阻。. cntdot. cm2.在微观水平上，单个结的电阻沿给定单元的周界沿着具有大的变化。这与冷冻断裂EM的图像一致，其中连接的网络从1-10股突然变化。该连接对大分子示踪剂是不可渗透的，具有9比1的Na+/Cl-区分，并且具有以下顺序的阳离子选择性：K+ > Na+ > Rb+ > Cs+ > Li+。封闭需要细胞外Ca 2+，但当细胞质中Ca 2+浓度增加时，连接打开。细胞骨架的结构成分（微管和微丝）似乎参与了连接事件，如免疫荧光特异性抗体染色所示。如果用细胞松弛素B处理细胞，肌动蛋白微丝就会紊乱，连接处打开，单层的电阻福尔斯下降。这种药物抑制紧密连接的重新密封。
When [canine kidney] MDCK cells are cultured in monolayers, they synthesize, assemble and seal occluding junctions that limit the paracellular route. These processes may be impaired by inhibitors of the protein synthesis but not by inhibitors of the synthesis of RNA. Once established, the occluding junctions confer to the monolayer an overall electrical resistance of 80-600 .OMEGA. .cntdot. cm2. At the microscopic level, the resistance of individual junctions have large variations along the perimeter of a given cell. This agrees with the images of freeze-fracture EM where the network of the junction varies abruptly from 1-10 strands. The junctions are impermeable to macromolecular tracers, have a 9 to 1 Na+/Cl- discrimination and have a cation selectivity following the order: K+ > Na+ > Rb+ > Cs+ > Li+. Sealing requires extracellular Ca2+, but the junctions open when the concentration of Ca2+ in the cytoplasm increases. The structural components of the cytoskeleton (microtubules and microfilaments) seem to be involved in the junctional events as revealed by staining with immunofluorescent specific antibodies. If the cells are treated with cytochalasin B, actin microfilaments disorganize, the junctions open and the electrical resistance across the monolayers falls. The resealing of the tight junction is inhibited by this drug.