Araki M, Sato F, Saito T
Department of Anatomy, Jichi Medical School, Tochigi, Japan.
Histochem J. 1987 Oct-Nov;19(10-11):579-88. doi: 10.1007/BF01687366.
In the matured chick retina, alkaline phosphatase (ALPase) activity is specifically localized in the outer plexiform layer and in horizontal and Müller cells. In the developing chick retina, ALPase activity is first recognized in growing neurites from horizontal cells during the 13th day of incubation, when synaptogenesis begins in the outer plexiform layer. Intraocular administration of ALPase inhibitors to developing chick embryos resulted in developmental disturbances in differentiation of the outer plexiform layer and also of photoreceptor cells. We have now extended these studies to an in vitro system. ALPase activity was studied by ultracytochemistry in cultured retinal cells from chick embryos, and the effects of specific ALPase inhibitor on retinal development were also analyzed. Two cell types showed intense ALPase activity: 1) flat glial cell, which formed a multi-layered epithelial sheet and 2) neuronal cell found within cell aggregates. Some cellular processes forming a neuropil-like structure within these aggregates also showed ALPase activity. When the ALPase inhibitor bromotetramisole was present in the culture medium, there was delay in aggregate formation and the development of neuritic processes was also affected. Moreover, this treatment also caused a considerable reduction in the number of photoreceptor cells present in the culture. The present results indicate that ALPase activity plays a significant role in retinal cell differentiation.
在成熟的雏鸡视网膜中，碱性磷酸酶（ALPase）活性特异性地定位于外网状层以及水平细胞和穆勒细胞中。在雏鸡视网膜发育过程中，在孵化第13天，当外网状层开始突触形成时，首次在水平细胞生长的神经突中检测到ALPase活性。对发育中的雏鸡胚胎进行眼内注射ALPase抑制剂，导致外网状层以及光感受器细胞分化出现发育障碍。我们现在已将这些研究扩展到体外系统。通过超微细胞化学研究了雏鸡胚胎培养视网膜细胞中的ALPase活性，并分析了特异性ALPase抑制剂对视网膜发育的影响。有两种细胞类型显示出强烈的ALPase活性：1）扁平胶质细胞，其形成多层上皮片；2）在细胞聚集体中发现的神经元细胞。在这些聚集体中形成类似神经毡结构的一些细胞突起也显示出ALPase活性。当培养基中存在ALPase抑制剂溴四咪唑时，聚集体形成延迟，神经突的发育也受到影响。此外，这种处理还导致培养物中存在的光感受器细胞数量显著减少。目前的结果表明，ALPase活性在视网膜细胞分化中起重要作用。
