RETINAL CROWDING ALTERS THE MORPHOLOGY OF ALPHA-GANGLION CELLS
RETINAL CROWDING ALTERS THE MORPHOLOGY OF ALPHA-GANGLION CELLS
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DOI：
10.1002/cne.902510408
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发表时间：
1986-09-22
影响因子：
2.5
通讯作者：
CHALUPA, LM
中科院分区：
文献类型：
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作者：
KIRBY, MA;CHALUPA, LM
已经假设单个视网膜神经节细胞的树突区域大小在发育早期通过邻近细胞之间的相互作用来调节(Wassle和Reiman，Proc.R.Soc.Lond.B.200：441-461，1978)。产前摘除导致剩余视网膜中神经节细胞密度增加的后果提供了检验该假设的机会（Chalupa 等人，Neuroscience 12：1139-1146，1984）。在本研究中，我们将正常视网膜中α神经节细胞的树突野直径与出生前（胚胎第42天和第51天）和出生后6天单眼摘除的成年猫的树突野直径进行了比较。在每只动物中，神经节细胞都被辣根过氧化物酶的中心感染标记。根据改进的 Hanker-Yates 程序孵育视网膜并进行整体安装。所有细胞均沿着由穿过视盘和中央区域绘制的线建立的走廊从颞视网膜取样。 α细胞基于其在内丛状层中的分层水平被分化成ON和OFF亚型(Peichl和Wassle，Proc.R.Soc.Lond.B.212：139-156，1981)。通过计算两个最长正交直径的平均值，从完整的细胞图中确定树突域和胞体直径。我们的主要发现是：1）早期单核摘除不会破坏成年动物剩余视网膜中 ON 和 OFF α 神经节细胞的镶嵌。 2)在采样的视网膜走廊内，在除远周边之外的所有偏心率处的产前去核的剩余视网膜中，α细胞的密度显着大于正常值。 3）在同等偏心率下，除最外周外，产前去核动物的树突野直径显着小于正常值。然而，当在同等细胞密度下进行比较时，发现产前去核动物和正常动物的树突区域尺寸相似。 4）在产前去核中，这些神经元的体细胞也明显小于正常细胞。 5）然而，如果单眼摘除是出生后的，则α细胞的密度和树突状区域直径与正常情况没有明显差异。这些结果表明，视网膜神经节细胞的形态可以通过增加发育中的神经节细胞的密度来影响。产前去核动物剩余视网膜中树突状区域和体细胞尺寸的减小可能反映了由于神经节细胞“拥挤”而导致的细胞相互作用的增加。这表明视网膜内的相互作用和轴突末端之间的竞争都有助于建立成人视网膜神经节细胞组织。
It has been hypothesized that the dendritic field size of individual retinal ganglion cells is regulated early in development by interactions among neighboring cells (Wassle and Reiman, Proc. R. Soc. Lond. B. 200:441-461, 1978). An opportunity to test this hypothesis is provided by the consequences of prenatal enucleation that results in an increased density of ganglion cells in the remaining retina (Chalupa et al., Neuroscience 12:1139-1146, 1984). In the present study we compared dendritic field diameters of alpha ganglion cells in normal retinas to those of adult cats that were monocularly enucleated before birth (on embryonic days 42 and 51) and 6 days after birth. In each animal ganglion cells were labeled by central infections of horseradish peroxidase. The retinas were incubated according to a modified Hanker-Yates procedure and whole-mounted. All cells were sampled from the temporal retina along a corridor established by a line drawn through the optic disk and the area centralis. Alpha cells were differentiated into ON and OFF subtypes on the basis of their level of stratification in the inner plexiform layer (Peichl and Wassle, Proc. R. Soc. Lond. B. 212:139-156, 1981). Dendritic field and soma diameters were determined from complete cell drawings by calculating the mean of the two longest orthogonal diameters. Our main findings are: 1) Early mononuclear enucleation does not disrupt the mosaics of ON and OFF alpha ganglion cells in the remaining retina of adult animals. 2) Within the retinal corridor sampled, the density of alpha cells was substantially greater than normal in the remaining retina of the prenatal enucleates at all eccentricities except the far periphery. 3) Except at the far periphery, the dendritic field diameters of the prenatally enucleated animals were significantly smaller than normal when compared at equivalent eccentricities. However, when compared at equivalent cell densities, dendritic field dimensions in the prenatally enucleated and normal animals were found to be similar. 4) In the prenatal enucleates the somas of these neurons were also significantly smaller than normal. 5) If the monocular enucleation was postnatal, however, the density and the dendritic field diameters of alpha cells did not differ appreciably from normal. These results indicate that the morphology of retinal ganglion cells can be influenced by increasing the density of developing ganglion cells. The reduced size of dendritic fields and somas in the remaining retina of prenatally enucleated animals may reflect increased cellular interactions due to ganglion cell "crowding." It is suggested that both intraretinal interactions and competition among axon terminals contribute to establishing the adult retinal ganglion cell organization.