Fukuda Y, Watanabe M
Departament of Physiology, Osaka University Medical School, Japan.
Rev Bras Biol. 1996 Dec;56 Su 1 Pt 1:69-78.
The optic nerve of adult mammals can regenerate when a permissive environment is provided with a peripheral nerve (PN) graft. Using this method of PN transplantation, we have studied regeneration of the optic nerve in adult cats. Number of retinal ganglion cells (RGCs) which regenerated their axons through the PN graft corresponds to 3-4% of the total RGC population. The RGCs with regenerated axons distributed widely from central to peripheral retinas. Of the known cell types of cat's RGCs, alpha, beta, gamma and other cells, alpha cells revealed the greatest capacity to regenerate their axons. Dendritic field diameters of most RGCs with regenerated axons were preserved. These regenerated axons were, however, mostly unmyelinated when surveyed by electron microscopy at two months after the transplantation surgery. The regenerated axons revealed normal physiological properties in response to visual stimuli and were classifiable into Y, X or W cells. In accordance with morphological data, Y cells (morphological alpha cells) were more frequently sampled than in normal retinas, whereas the occurrences of X cells (morphological beta cells) and other cells were unchanged or decreased. These results suggest that RGCs retain their physiological function during axonal regeneration, and RGCs with large soma and large dendritic field (Y or alpha cells) have the greatest capacity to regenerate their axons.
当提供一个允许性环境并植入外周神经（PN）移植物时，成年哺乳动物的视神经能够再生。利用这种PN移植方法，我们研究了成年猫视神经的再生情况。通过PN移植物再生轴突的视网膜神经节细胞（RGC）数量相当于RGC总数的3%-4%。轴突再生的RGC从视网膜中央到周边广泛分布。在猫已知的RGC细胞类型中，α、β、γ及其他细胞类型中，α细胞显示出最强的轴突再生能力。大多数轴突再生的RGC的树突野直径得以保留。然而，在移植手术后两个月通过电子显微镜观察发现，这些再生轴突大多没有髓鞘。再生轴突在对视觉刺激的反应中显示出正常的生理特性，并且可分为Y、X或W细胞。与形态学数据一致，Y细胞（形态学上的α细胞）比正常视网膜中更频繁地被检测到，而X细胞（形态学上的β细胞）和其他细胞的出现频率未变或有所降低。这些结果表明，RGC在轴突再生过程中保留了它们的生理功能，并且具有大胞体和大树突野的RGC（Y或α细胞）具有最强的轴突再生能力。
