Segmental differentiations of cell junctions in the vascular endothelium. Arteries and veins
Segmental differentiations of cell junctions in the vascular endothelium. Arteries and veins
复制标题
血管内皮细胞连接的节段分化。
作者：
M. Simionescu;N. Simionescu;G. Palade
在大鼠中，使用冷冻裂解制剂对弹性（主动脉）和肌性（肠系膜）动脉以及中等（肾和肠系膜）和大（下腔）静脉中的内皮连接进行了系统研究。动脉内皮具有闭塞连接和交通连接（缝隙连接）的复合体，与小动脉中描述的复合体相当，但不如小动脉中描述的复合体详细。闭塞连接的颗粒表现为“单个单元”颗粒，并且在膜裂解时倾向于保留在B面上。在静脉内皮中，连接采取长闭塞连接的形式，几乎没有相关的交通连接（交通斑）。与动脉内皮细胞一样，在裂解的标本中，连接颗粒优先出现在B面上。这些结构虽然在长距离上是连续的，但局部被连接元件类似于小静脉中发现的连接元件的区域中断：脊和槽短、不连续、沿着细胞接触的总线随机分布，并且通常无颗粒。在肌性动脉中，会遇到两种不寻常的连接类型。两者都沿着电池的周边沿着短距离地布置成环。一种类型似乎是动脉内皮的闭塞和交通连接的通常组合的拉伸版本（这种类型偶尔也会在静脉内皮中遇到）。另一种类型让人想起无脊椎动物上皮中发现的分隔连接，但明显的相似性仍有待进一步的工作来验证。
A systematic survey of endothelial junctions in elastic (aorta) and muscular (mesenteric) arteries and in medium (renal and mesenteric) and large (cava inferior) size veins has been carried out in the rat using freeze-cleaved preparations. The arterial endothelium is provided with a complex of occluding and communicating junctions (gap junctions) comparable to, though less elaborate than, that described in arterioles. The particles of the occluding junctions behave like "single unit" particles and have the tendency to remain on B faces upon membrane cleavage. In the venous endothelium the junctions take the form of long occluding junctions with few associated communicating junctions (maculae communicantes). As in arterial endothelium, the junctional particles appear preferentially on B faces in cleaved preparations. These structures, although continuous over long distances, are interrupted focally by areas in which the junctional elements are similar to those found in venules: the ridges and grooves are short, discontinuous, randomly distributed along the general line of cell contact, and often particle-free. In muscular arteries two unusual types of junctions are encountered. Both are disposed in loops over short distances along the perimeter of the cell. One type appears to be a strectched-out version of the usual combination of occluding and communcating junctions of the arterial endothelium (this type is also occasionally encountered in the venous endothelium). The other type is reminiscent of the septate junctions found in the epithelia of invertebrates but the apparent similarity remains to be checked by further work.