ANALYSIS OF THE RETINAS AND OPTIC NERVES OF ACHIASMATIC BELGIAN SHEEPDOGS
ANALYSIS OF THE RETINAS AND OPTIC NERVES OF ACHIASMATIC BELGIAN SHEEPDOGS
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DOI：
10.1002/cne.903520305
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发表时间：
1995-02-13
影响因子：
2.5
通讯作者：
WILLIAMS, RW
中科院分区：
文献类型：
--
作者：
HOGAN, D;WILLIAMS, RW
在一个黑色比利时牧羊犬家族中携带的常染色体隐性突变消除了视交叉--所有视网膜神经节细胞轴突直接延伸到同侧视束。我们试图解决的一个关键问题是，视网膜或交叉是突变基因作用的主要部位。在这项研究中，我们检查了突变动物的视网膜，以发现视网膜结构的任何相关变化。突变动物的视网膜相对正常。内核层和外核层在性质上与正常犬的核层没有什么区别。主要区别是突变体的中央面积较小，峰值神经节细胞密度低于正常犬(8,100比10,500/mm(2)，P<；0.05)。这种突变表型与暹罗猫和白化雪貂的视网膜相似。在中央区以外，突变型神经节细胞密度的中心到外周的梯度是正常的。视神经的大小、轴突密度和轴突总数在突变犬和正常犬之间没有差异。三只突变犬中有一只有轻微的异常视交叉。神经节细胞的逆行标记表明，残留的交叉投射来自鼻视网膜广泛区域的细胞，而不是像抗白化病所预期的那样仅来自鼻周区域。尽管我们的分析不排除视网膜是突变基因作用的部位，但突变视网膜和正常视网膜之间的微小差异表明，突变要么作用于视网膜外，要么仅对神经节细胞的轨迹产生高度特异性的影响。(C)1995年Wiley-Liss公司
An autosomal recessive mutation carried in a family of black Belgian sheepdogs eliminates the optic chiasm-all retinal ganglion cell axons extend directly into the ipsilateral optic tract. One key issue we are trying to resolve is whether the retina or the chiasm is the principal site of mutant gene action. In this study, we have examined retinas of mutants to discover any associated changes in retinal structure.Retinas of mutant animals are relatively normal. Inner and outer nuclear layers are qualitatively indistinguishable from those of normal dogs. The principal difference is that the area centralis of mutants is smaller and has a lower peak ganglion cell density than that of normal dogs (8,100 vs. 10,500/mm(2), P < 0.05). This mutant phenotype is similar to that seen in retinas of Siamese cats and albino ferrets. Beyond area centralis, the central-to-peripheral gradient in ganglion cell density is normal in mutants. The size of the optic nerves, density of axons, and total number of axons do not differ between mutant and normal dogs.One of three mutant dogs had a small abnormal optic chiasm. Retrograde labeling of ganglion cells demonstrated that the residual crossed projection originated from cells in a widespread region in nasal retina and not solely from the peripheral nasal region, as might be expected of an anti-albino.Although our analysis does not rule out the retina as a site of mutant gene action, the modest differences between mutant and normal retinas suggest that the mutation either acts outside the retina or exerts a highly specific effect on ganglion cell trajectories alone. (C) 1995 Wiley-Liss, Inc.