Graydon M L, Giorgi P P
J Anat. 1984 Aug;139 ( Pt 1)(Pt 1):145-57.
Cell distribution in the retinal ganglion cell layer of Xenopus laevis was studied by electron microscopy and the retinal wholemount method. Unlike the familiar stratification of the retina, the ganglion cell perikarya and their axons were localised in the same layer, but strictly segregated in alternate rows converging in a radial pattern on the optic disc. Rows of perikarya (retinal cords) were two to ten cells wide and clearly defined for a little more than half the distance between the optic disc and the ora serrata. Detailed analysis of 25% of the retinal surface showed higher cell density (about 3500 cells/mm2) in the centrodorsal region than in the periphery (about 2000 cells/mm2). The higher density regions represent a weak visual streak having no nasotemporal asymmetry. After staining with cresyl violet, the majority of cells appeared to be small (10 micron diameter) with very little Nissl substance. The cytoplasm was scant; this was confirmed by electron microscopy. The difference between the total cell count (68470 +/- 7360) and the total axon count in the optic nerve (Wilson, 1971) suggests a population of 15% non-ganglionic cells (glia and amacrine cells) in the retinal ganglion cell layer. Retinal ganglion cell topography in Xenopus may have relevance to studies on retinal growth and retinotopy. The functional significance of the weak visual streak in Xenopus is consistent with a limited need for visual acuity.
采用电子显微镜和视网膜铺片法研究了非洲爪蟾视网膜神经节细胞层中的细胞分布。与常见的视网膜分层不同，神经节细胞的胞体及其轴突位于同一层，但在向视盘呈放射状汇聚的交替行中严格分离。胞体行（视网膜索）宽2至10个细胞，在视盘与锯齿缘之间距离的略超过一半处清晰可辨。对25%的视网膜表面进行详细分析显示，中央背侧区域的细胞密度（约3500个细胞/mm²）高于周边区域（约2000个细胞/mm²）。高密度区域代表一条微弱的视带，没有鼻颞侧不对称性。经甲酚紫染色后，大多数细胞似乎较小（直径10微米），尼氏体很少。细胞质稀少；这一点通过电子显微镜得到了证实。细胞总数（68470±7360）与视神经中轴突总数之间的差异（Wilson，1971）表明，视网膜神经节细胞层中有15%的非神经节细胞（神经胶质细胞和无长突细胞）。非洲爪蟾视网膜神经节细胞的拓扑结构可能与视网膜生长和视网膜拓扑学研究相关。非洲爪蟾中微弱视带的功能意义与对视敏度的有限需求相一致。
