Electrophysiological and molecular biological studies on axotomized and regenerating cat retinal ganglion cells

1.再生猫视神经纤维的视觉功能：将一段周围神经移植到成年猫视神经节段上。60~90天后，从移植的PN中再生的RGC轴突中记录单个单位，并检测它们的感受野特性。这些单位记录中的大多数可以被识别为Y、X或W细胞，尽管Y细胞是最频繁的采样。2.再生视网膜节细胞的形态鉴定：细胞内注射HRP后，根据再生视网膜节细胞树突状突起在IPL内的延伸程度，将其分为视网膜区视网膜区和视网膜区视网膜区。在β和γ细胞中，中心型细胞的比例高于偏心型细胞，这与生理取材的预期一致。然而，在一个偏离中心的细胞样本中，细胞数量超过了细胞，这是相当出人意料的。3.环境光对CAT…存活和再生的影响视网膜神经节细胞增多：在完全黑暗条件下饲养的PN移植猫，再生的视网膜节细胞数量少于在正常光/暗环境中饲养的猫，并且经常遇到死亡或退化的视网膜节细胞，这表明环境光对猫视网膜节细胞的存活和再生是必不可少的。4.神经营养因子对猫视网膜节细胞存活和轴突再生的促进作用：眼内注射脑源性神经营养因子、神经营养因子和神经营养因子后14天的猫视网膜节细胞的存活率均较未处理的对照组增加，其中以β细胞作用最为明显。在神经营养因子和CNTF中加入Forsklin进一步促进PN移植后视网膜节细胞的再生率。5.视神经切断后2周内猫视网膜节细胞存活及感受野特性：在细胞内注射染料的形态学研究中，近80%的β细胞在视神经切断后7天死亡，而甚至有70%的细胞在视神经切断后14天存活。在存活5天的视网膜节细胞的生理记录中，我们记录了X细胞和Y细胞，尽管其中一些细胞的感受野比正常小，但在存活14天时，几乎只采集了Y细胞，再次表明在猫的视网膜中，Y细胞比X细胞对轴突切断的抵抗力更强。较少

1. Visual functions of regenerated cat optic nerve fibers : A piece of peripheral nerve (PN) was grafted to the sectioned optic nerve of adult cats. 60-90 days later, single unit recordings were made from regenrated RGCs axons in the PN graft and their receptive field properties were examined. Most of these unit recordings could be identified as Y, X or W cells, though Y cells were being most frequently sampled. 2. Morphological identifications of regenerated cat RGCs into ON center or OFF center types : After intracellular HRP injections and vertical sections of regenerated RGCs, we identified them into ON center or OFF center types according to the level of their dendritic extensions within the IPL. Proportions of ON center types were higher than OFF center types among β and γ cells, as expected from physiological samplings. However, in the sample of a cells OFF center cells outnumbered, which was quite unexpected. 3. Effects of environmental light on survival and regeneration of cat … More RGCs : In PN grafted cats, reared in complete darkness, we found that the number of regenerated RGCs were less than those reared in normal light/dark environment and that dying or degenerating RGCs were frequently encountered, indicating that environmental light is essential for the survival and regeneration of cat RGCs. 4. Facilitatory effects of neurotrophins on the survival and axonal regeneration of cat RGCs : After intraocular injections of each of the BDNF, CNTF and GDNF, the survival of cat RGCs, evaluated at 14 days after axotomy, increased as compared with the untreated controls, the effect being most significant among β cells. Addition of forskolin to BDNF and CNTF further facilitated regeneration ratios of axotomized RGCs after PN graft. 5. Cell survival and receptive field properties of axotomized cat RGCs within 2 weeks after optic nerve sections : In morpohological studies with intracellular dye injections we noted that almost 80% of β cells died at 7 days after axotomy, while even 70% of a cells survived at 14 days after axotomy. In physiological recordings from axotomized RGCs at 5 days survival, we recorded X cells as well as Y cells though some of them having smaller receptive fields than normal, at 14 days survival, on the other hand, almost exclusively Y cells were sampled, indicating again that Y cells are more resistant to axotomy than X cells in the cat retina. Less