Zhang Jian, Wu Samuel M
Cullen Eye Institute, Baylor College of Medicine, Houston, Texas 77030, USA.
J Comp Neurol. 2003 Jun 23;461(2):276-89. doi: 10.1002/cne.10704.
By using double-label immunocytochemistry and confocal microscopy, we studied rod and cone synaptic contacts, photoreceptor-bipolar cell convergence, and patterns of axon terminal ramification of ON bipolar cells in the tiger salamander retina. An antibody to recoverin, a calcium-binding protein found in photoreceptors and other retinal neurons in various vertebrates, differentially labeled rods and cones by lightly staining rod cell bodies, axons, and synaptic pedicles and heavily staining cone cell bodies and pedicles. An antibody to G(oalpha) labeled most ON bipolar cells, with axon terminals ramified mainly in strata 6-9 and a minor band in stratum 3 of the inner plexiform layer (IPL). Stratum 10 of the IPL was G(oalpha) negative, and previous studies showed that axon terminals of rod-dominated ON bipolar cells are monostratified in that stratum. The axonal morphology of G(oalpha)-positive cells resembled that of the cone-dominated (DBC(C)) or mixed rod and cone ON (DBC(M)) bipolar cells. The G(oalpha)-positive dendritic processes made close contact with all cone pedicles and superficial contact with some rod pedicles, consistent with the idea that G(oalpha) subunits are present in DBC(C)s and DBC(M)s. The size and density of these cells were analyzed, and their spatial distributions were determined. To our knowledge, this is the first study to characterize photoreceptor inputs and axon terminal morphology of a population of ON bipolar cell with the use of a G(oalpha) antibody as an immunomarker in the salamander retina.
通过使用双标记免疫细胞化学和共聚焦显微镜技术，我们研究了虎螈视网膜中视杆和视锥突触连接、光感受器 - 双极细胞汇聚以及ON双极细胞轴突终末分支模式。恢复蛋白是一种在各种脊椎动物的光感受器和其他视网膜神经元中发现的钙结合蛋白，针对它的抗体通过轻度染色视杆细胞体、轴突和突触小足以及重度染色视锥细胞体和小足来区分标记视杆和视锥。针对G(oα)的抗体标记了大多数ON双极细胞，其轴突终末主要在内部网状层（IPL）的第6 - 9层分支，在第3层有一小条带分支。IPL的第10层为G(oα)阴性，先前的研究表明，视杆主导的ON双极细胞的轴突终末在该层呈单分层。G(oα)阳性细胞的轴突形态类似于视锥主导的（DBC(C)）或视杆和视锥混合的ON（DBC(M)）双极细胞。G(oα)阳性的树突状突起与所有视锥小足紧密接触，与一些视杆小足有表面接触，这与DBC(C)和DBC(M)中存在G(oα)亚基的观点一致。我们分析了这些细胞的大小和密度，并确定了它们的空间分布。据我们所知，这是首次在蝾螈视网膜中使用G(oα)抗体作为免疫标记物来表征一群ON双极细胞的光感受器输入和轴突终末形态的研究。
