Gipson I K, Anderson R A
Invest Ophthalmol Vis Sci. 1979 Jun;18(6):547-61.
With subfragment-one of myosin used as the histochemical marker, actin filament distribution was mapped in cells of the aqueous outflow pathway. In uveal, corneal-scleral and juxtacanalicular meshwork cells, bundles of actin filaments were present along the basal cytoplasm. Some of these bundles terminated at adhesion plaques. Juxtacanalicular meshwork cells contained, in addition to bundles, randomly oriented actin filaments at the end of cell extensions. Giant vacuoles in the inner wall of Schlemm's canal did not have actin filaments associated with their membranes; there were, however, intermediate filaments present along the membrane. Bundles of actin filaments were also found within the cells of both inner and external walls of Schlemm's canal. Cells of both the meshwork and inner wall of Schlemm's canal had actin filaments extending out into the cytoplasm from cell junctions. In all areas of the meshwork and especially in the area external to Schlemm's canal, cells were observed which had a cytoplasm, very rich in actin filaments. These cells had characteristics common to smooth muscle cells. The actin filaments of cells of the aqueous outflow pathway could have any or all of several functions. Bundles of filaments in the meshwork could contract to lift and separate trabecular sheets and/or, through their association with adhesion plaques, they could stabilize cells on their collagen substrate, thus acting as cytoskeletal struts. Randomly oriented actin filaments, noted particularly in cells of the juxtacanalicular meshwork, may play a role in phagocytosis. Actin filaments found in association with junctions may be important structures for maintaining cell-to-cell contacts. Lack of actin filaments around giant vacuoles in Schlemm's canal indicates that they do not play a role in shuttling aqueous across the endothelium of the canal. The significance of "actin-rich" cells in the meshwork and those external to Schlemm's canal is unknown.
以肌球蛋白亚片段-1作为组织化学标记物，绘制了房水流出途径细胞中肌动蛋白丝的分布。在葡萄膜、角膜巩膜和小梁网细胞中，肌动蛋白丝束沿基底细胞质存在。其中一些丝束终止于黏着斑。除了丝束外，小梁网细胞在细胞突起末端还含有随机排列的肌动蛋白丝。施莱姆管内壁的巨大液泡膜上没有肌动蛋白丝；然而，沿膜存在中间丝。在施莱姆管内外壁细胞内也发现了肌动蛋白丝束。小梁网和施莱姆管内壁细胞都有肌动蛋白丝从细胞连接处延伸到细胞质中。在小梁网的所有区域，尤其是在施莱姆管外部区域，观察到一些细胞，其细胞质中富含肌动蛋白丝。这些细胞具有平滑肌细胞的共同特征。房水流出途径细胞的肌动蛋白丝可能具有以下几种功能中的任何一种或全部。小梁网中的丝束可以收缩以提起和分开小梁薄片，和/或通过它们与黏着斑的关联，它们可以将细胞稳定在其胶原基质上，从而充当细胞骨架支柱。特别是在小梁网细胞中发现的随机排列的肌动蛋白丝可能在吞噬作用中起作用。与连接处相关的肌动蛋白丝可能是维持细胞间接触的重要结构。施莱姆管中巨大液泡周围缺乏肌动蛋白丝表明它们在房水穿过管内皮的穿梭过程中不起作用。小梁网和施莱姆管外部“富含肌动蛋白”细胞的意义尚不清楚。
