Leventhal A G, Schall J D, Ault S J
Department of Anatomy, University of Utah School of Medicine, Salt Lake City 84132.
J Neurosci. 1988 Jun;8(6):2028-38. doi: 10.1523/JNEUROSCI.08-06-02028.1988.
The degree to which a retinal ganglion cell's environment can affect its morphological development was studied by manipulating the distribution of ganglion cells in the developing cat retina. In the newborn kitten there is an exuberant ganglion cell projection from temporal retina to the contralateral lateral geniculate nucleus (LGNd) (Leventhal et al., 1988) and from nasal retina to the ipsilateral LGNd. Neonatal, unilateral optic tract section results in the survival of many of these ganglion cells (Leventhal et al., 1988). The morphology of ganglion cells which survive in regions of massively reduced ganglion cell density was studied. As reported previously (Linden and Perry, 1982; Perry and Linden, 1982; Ault et al., 1985; Eysel et al., 1985), we found that the dendritic fields of all types of ganglion cells on the border of an area depleted of ganglion cells extended into the depleted area. The cell bodies and dendritic fields of alpha and beta cells within depopulated areas, as well as on the borders of the depopulated areas, were larger than normal. The dendritic fields of these cells also exhibited abnormal branching patterns. For alpha and beta cell types the relative increase in size tended to be greatest where the relative change in density was the greatest. In fact, isolated beta cells within the cell-poor area centralis region resembled normal central alpha cells in the cell-rich region of the area centralis in the same retina. Interestingly, in the same regions of reduced density where alpha and beta cells were dramatically larger than normal, the cell body and dendritic field sizes of other cell types (epsilon, g1 and g2 were unchanged. These results indicate that neuronal interactions during development contribute to the morphological differentiation of retinal ganglion cells and that different mechanisms mediate the morphological development of different classes of cells in cat retina.
通过操纵发育中的猫视网膜中神经节细胞的分布，研究了视网膜神经节细胞的环境对其形态发育的影响程度。新生小猫中，存在从颞侧视网膜到对侧外侧膝状体核（LGNd）（Leventhal等人，1988年）以及从鼻侧视网膜到同侧LGNd的旺盛神经节细胞投射。新生期单侧视神经切断会导致许多这些神经节细胞存活（Leventhal等人，1988年）。研究了在神经节细胞密度大幅降低区域中存活的神经节细胞的形态。如先前报道（Linden和Perry，1982年；Perry和Linden，1982年；Ault等人，1985年；Eysel等人，1985年），我们发现神经节细胞缺失区域边界上所有类型神经节细胞的树突野延伸到了缺失区域。细胞缺失区域内以及缺失区域边界上的α和β细胞的胞体和树突野比正常的大。这些细胞的树突野还表现出异常的分支模式。对于α和β细胞类型，密度相对变化最大的地方，其大小的相对增加往往最大。实际上，细胞贫乏的中央凹区域内的孤立β细胞类似于同一视网膜中细胞丰富的中央凹区域中的正常中央α细胞。有趣的是，在α和β细胞比正常大得多的相同密度降低区域，其他细胞类型（ε、g1和g2）的胞体和树突野大小没有变化。这些结果表明，发育过程中的神经元相互作用有助于视网膜神经节细胞的形态分化，并且不同的机制介导了猫视网膜中不同类型细胞的形态发育。
