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（PN）移植到成年猫的视神经切片上。60-90天后，从PN移植物中再生的RGCs轴突进行单单位记录，并检查其感受野特性。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细胞被最频繁地采样。2.再生猫视网膜神经节细胞ON中心型和OFF中心型的形态学鉴定：细胞内注射HRP后，将再生的视网膜神经节细胞垂直切片，根据其在IPL内的树突延伸水平将其分为ON中心型和OFF中心型。在β和γ细胞中，ON中心类型的比例高于OFF中心类型，正如生理采样所预期的那样。然而，在细胞样本中，偏离中心的细胞数量超过了，这是相当出乎意料的。3.环境光对猫存活和再生的影响 关于我们 RGC：在PN移植猫中，在完全黑暗中饲养，我们发现再生的RGCs的数量比在正常光/暗环境中饲养的少，并且经常遇到死亡或退化的RGCs，表明环境光对猫RGCs的存活和再生是必不可少的。4.神经营养因子对猫RGCs存活和轴突再生的促进作用：眼内注射BDNF、CNTF和GDNF后，在轴突切断后14天评估的猫RGCs存活率与未处理的对照组相比增加，该作用在β细胞中最显著。在BDNF和CNTF中加入forskolin进一步促进了PN移植后轴突切断的RGCs的再生率。5.视神经切片后2周内轴突切断的猫RGCs的细胞存活和感受野特性：在细胞内染料注射的形态学研究中，我们注意到几乎80%的β细胞在轴突切断后7天死亡，而甚至70%的α细胞在轴突切断后14天存活。在存活5天的轴突切断的RGC的生理记录中，我们记录了X细胞以及Y细胞，尽管它们中的一些具有比正常更小的感受野，另一方面，在存活14天时，几乎仅Y细胞被取样，再次表明在猫视网膜中Y细胞比X细胞对轴突切断更具抗性。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