Métin C, Irons W A, Frost D O
Institut Alfred Fessard, CNRS UPR 2212, Gif-sur-Yvette, France.
J Comp Neurol. 1995 Mar 6;353(2):179-99. doi: 10.1002/cne.903530203.
We examined the number, spatial distribution, and size of ganglion cells in the retinae of normal Syrian hamsters and hamsters with retinal projections to the auditory and somatosensory nuclei of the thalamus, induced by neonatal surgery. As revealed by retrograde filling with horseradish peroxidase, there are about 64,600 contralaterally projecting retinal ganglion cells (RGCs) and 1,700 ipsilaterally projecting RGCs in the retinae of normal adult hamsters. Contralaterally projecting RGCs are distributed throughout the retina and have two local density peaks located within a central streak of high RGC density that is oriented approximately along the nasal-temporal axis. RGC density falls above and below the central streak, with a steeper gradient towards the upper retina. Ipsilaterally projecting RGCs are diffusely distributed within a crescent at the inferotemporal retinal periphery and are most dense at the internal border of the crescent. The soma diameter of contralaterally projecting RGCs ranges from 6 to 25 microns; the diameter distribution is unimodal, with a peak in the 10-13 microns range and is skewed toward smaller values, with an elongated tail towards higher values. Contralaterally projecting RGCs tend to be smaller in regions of higher density. Ipsilaterally projecting RGCs tend to be larger than contralaterally projecting RGCs both globally and within the temporal crescent, and their size distributions tend to be less regular and less well related to local density. The retinae of neonatally operated hamsters with novel retinal projections to the auditory. and somatosensory systems contain about one-fourth the normal number of contralaterally projecting RGCs, whose relative density distribution is approximately normal despite the drastic reduction of absolute RGC density. The range and distribution of RGC soma diameters are similar in normal and neonatally operated hamsters, and, in operated as in normal hamsters, contralaterally projecting RGC somata tend to be smaller in regions of higher density. Our results in normal hamsters suggest a role for intraretinal mechanisms in the determination of RGC size. Our findings in neonatally operated hamsters suggest that, despite the reduced number of RGCs in these animals, the same types of RGCs are found in the retinae of normal and neonatally operated hamsters.
我们研究了正常叙利亚仓鼠以及经新生儿手术诱导视网膜投射至丘脑听觉和躯体感觉核的仓鼠视网膜中神经节细胞的数量、空间分布和大小。用辣根过氧化物酶逆行填充显示，正常成年仓鼠视网膜中有约64,600个对侧投射的视网膜神经节细胞（RGC）和1,700个同侧投射的RGC。对侧投射的RGC分布于整个视网膜，在一条大致沿鼻颞轴排列的高RGC密度中央条纹内有两个局部密度峰值。RGC密度在中央条纹上方和下方下降，朝向上方视网膜的梯度更陡。同侧投射的RGC分散分布在颞下视网膜周边的一个新月形区域内，在新月形区域的内边界处最为密集。对侧投射的RGC的胞体直径范围为6至25微米；直径分布呈单峰，在10 - 13微米范围内有一个峰值，且向较小值倾斜，有一个朝较高值延伸的长尾。对侧投射的RGC在高密度区域往往较小。同侧投射的RGC在整体上以及在颞侧新月形区域内往往比对侧投射的RGC大，并且它们的大小分布往往不太规则，与局部密度的相关性也较差。经新生儿手术且视网膜有新的投射至听觉和躯体感觉系统的仓鼠视网膜中，对侧投射的RGC数量约为正常数量的四分之一，尽管绝对RGC密度大幅降低，但其相对密度分布大致正常。正常仓鼠和经新生儿手术的仓鼠中RGC胞体直径的范围和分布相似，并且与正常仓鼠一样，在经手术的仓鼠中，对侧投射的RGC胞体在高密度区域往往较小。我们在正常仓鼠中的研究结果表明视网膜内机制在RGC大小的决定中起作用。我们在经新生儿手术的仓鼠中的研究结果表明，尽管这些动物中的RGC数量减少，但在正常仓鼠和经新生儿手术的仓鼠视网膜中发现了相同类型的RGC。
