Distribution of bipolar input to midget and parasol ganglion cells in marmoset retina
Distribution of bipolar input to midget and parasol ganglion cells in marmoset retina
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DOI：
10.1017/s0952523808080073
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发表时间：
2008-01-01
影响因子：
1.9
通讯作者：
Grunert, Ulrike
中科院分区：
文献类型：
--
作者：
Erikoz, Bahar;Jusuf, Patricia R.;Grunert, Ulrike
不同类型的视网膜神经节细胞在其响应特性上表现出差异。在这里，我们调查的问题，这些差异是否与分布的突触输入的树突树。我们测量了一只新大陆猴（绒猴，Callithrix jacchus）视网膜中侏儒和阳伞神经节细胞树突的突触输入的分布和密度。神经节细胞逆行标记染料注射到小细胞或大细胞区域的外侧膝状体核，随后光填充。假定的双极细胞突触进行了鉴定，免疫细胞化学使用的带状蛋白CtBP 2或AMPA受体的GluR4亚基的抗体。对于所有的细胞，共定位的免疫反应斑点分布在整个树突状树。两种突触标记物的假定的双极输入到侏儒神经节细胞的密度是相当的，这表明AMPA受体GluR4亚基在侏儒双极和侏儒神经节细胞之间的所有突触处表达。侏儒神经节细胞每100 μ m（2）树突表面平均有9个共定位的免疫反应点，而梧桐细胞每100 μ m（2）树突表面平均有7个共定位的免疫反应点。树突树的不同区域的密度是相当的，并且不受细胞相对于中央凹的位置的影响。我们的研究结果表明，侏儒和阳伞细胞的反应特性的差异不是由于突触输入到树突树的密度的差异。
Different types of retinal ganglion cell show differences in their response properties. Here we investigated the question of whether these differences are related to the distribution of the synaptic input to the dendritic tree. We measured the distribution and density of synaptic input to the dendrites of midget and parasol ganglion cells in the retina of a New World monkey, the marmoset, Callithrix jacchus. Ganglion cells were retrogradely labeled by dye injection into parvocellular or magnocellular regions of the lateral geniculate nucleus and subsequently photo-filled. Presumed bipolar cell synapses were identified immunocytochemically using antibodies against the ribbon protein CtBP2 or the GluR4 subunit of the AMPA receptor. For all cells, colocalized immunoreactive puncta were distributed across the entire dendritic tree. The density of the presumed bipolar input to midget ganglion cells was comparable for both synaptic markers, suggesting that the AMPA receptor GluR4 subunit is expressed at all synapses between midget bipolar and midget ganglion cells. Midget ganglion cells had an average of nine colocalized immunoreactive puncta per 100 mu m(2) dendritic surface, and parasol cells had an average of seven colocalized immunoreactive puncta per 100 mu m(2) dendritic surface. The densities were comparable in different regions of the dendritic tree and were not influenced by the location of the cells with respect to the fovea. Our findings suggest that the differences in the response characteristics of midget and parasol cells are not due to differences in the density of synaptic input to their dendritic tree.