Mechanism of controlling blood-cell passage between the sinus endothelial cells

采用冻裂法和清洗剂萃取法对大鼠脾窦内皮细胞间的连接进行了电镜观察。观察到粘附和紧密连接。粘附连接是内皮细胞之间主要的连接结构，位于基底外侧和外侧表面。在基底外侧粘附连接处，肌动蛋白丝与连接膜相连，并与应力纤维中的肌动蛋白丝连续。在粘附结点的间隙存在交叉桥，桥的间距较为规则。在内皮细胞之间也观察到一种紧密连接的形式，斑斑闭塞，但并非在每个细胞相邻处都观察到。电子密集的物质，在紧密连接的细胞膜细胞质表面，将连接膜与大量的细丝分开。在基底外侧紧密连接处，肌动蛋白丝与应力纤维中的肌动蛋白丝连续。基于这些观察，这两个细胞间连接被认为在鼻窦功能中起重要作用。

Junctions between the sinus endothelial cells of rat spleen were examined by electron microscopy, using both freeze-fracture and detergent-extraction techniques. Adherens and tight junctions were observed. Adherens junctions were the predominant junctional structures between endothelial cells and were located on basolateral and lateral surfaces. At the basolateral adherens junctions, actin filaments were associated with the junctional membrane and were continuous with actin filaments in stress fibers. Cross-bridges were present in the interspaces of the adherens junctions, and spacings of the bridges were fairly regular. A form of tight junction, macula occludens, was also observed between the endothelial cells, it was not observed at every cellular apposition. Electron-dense material, adjoiningthe cytoplasmic surfaces of membranes in the tight junctions, separated the junctional membranes from masses of thin filaments. At basolateral tight junctions, the actin filaments were continuous with those in the stress fibers. Based on these observations, these two intercellular junctions were considered to play important roles in sinus functions.