Nurcombe V, Bennett M R
Exp Brain Res. 1981;44(3):249-58. doi: 10.1007/BF00236562.
When HRP is injected into the optic tecta of embryonic or newly hatched chicks, the ganglion cells in the contralateral retina can be successfully dissociated into culture and identified at any time by appropriate histochemical staining. Histological examination of whole mounts of retinae both ipsilateral and contralateral to an injection site indicated that no HRP diffused out of an injected tectum, and that the only reaction product that could be visualized was restricted to the ganglion cell layer of the contralateral eye. Because retinal ganglion cells are the only retinal neurons to project to the optic tectum, the intraxonal retrograde transport of HRP to these cells allows their unequivocal identification from amongst the heterogeneous population of retinal neurons present after dispersal into single cells in monolayer culture. The presence of HRP in the cell bodies did not appear to impair their ability to survive, grow or express neurites. Counts of labeled cells from progressively aged birds confirmed that the peak number of generated ganglion cells occurs on embryonic day 10,and that is a 40% decline in the number these neurons over the following 3 days. However, when labelled ganglion cells from 10 day embryos were grown in culture with optic tectum, all the ganglion cells survived over the following 4 days, including those destined to die in vivo. This trophic effect cannot be induced by cerebellum, but is partly induced by media first conditioned over tectal cells. The trophic effect exerted by optic tectum appears therefore to be specific and chemically mediated. We suggest that the death of retinal ganglion cells in vivo may be a consequence of the inability of some cells to establish adequate supplies of a growth factor from the optic tectum.
当将辣根过氧化物酶（HRP）注入胚胎期或新孵出小鸡的视顶盖时，对侧视网膜中的神经节细胞能够成功地解离出来进行培养，并可随时通过适当的组织化学染色加以识别。对注射部位同侧和对侧视网膜的整装标本进行组织学检查表明，没有HRP从注射的视顶盖中扩散出来，并且唯一能观察到的反应产物局限于对侧眼的神经节细胞层。由于视网膜神经节细胞是视网膜中唯一投射到视顶盖的神经元，HRP向这些细胞的轴内逆行运输使得在分散为单层培养中的单细胞后，能够从视网膜神经元的异质群体中明确识别出它们。细胞体中HRP的存在似乎并未损害它们存活、生长或长出神经突的能力。对不同年龄鸟类标记细胞的计数证实，神经节细胞生成的峰值出现在胚胎第10天，并且在接下来的3天里这些神经元的数量下降了40%。然而，当将来自10日龄胚胎的标记神经节细胞与视顶盖一起在培养中生长时，所有神经节细胞在接下来的4天里都存活了下来，包括那些在体内注定会死亡的细胞。这种营养作用不能由小脑诱导，但部分可由首先在顶盖细胞上条件化的培养基诱导。因此，视顶盖施加的营养作用似乎是特异性的且由化学物质介导。我们认为，体内视网膜神经节细胞的死亡可能是一些细胞无法从视顶盖建立充足生长因子供应的结果。
