Glutamate receptors in the rod pathway of the mammalian retina
Glutamate receptors in the rod pathway of the mammalian retina
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DOI：
10.1523/jneurosci.21-21-08636.2001
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发表时间：
2001-11-01
影响因子：
5.3
通讯作者：
Wässle, H
中科院分区：
文献类型：
--
作者：
Ghosh, KK;Haverkamp, S;Wässle, H
哺乳动物视网膜的视杆双极（RB）细胞以分级的、光依赖的方式从20至40个带状突触（二分体）释放谷氨酸。在二分体中，两类无长突细胞，AI和AII细胞，是突触后伴侣。我们研究了谷氨酸受体（GluRs）的表达AI和AII细胞使用免疫细胞化学与特异性抗体对GluR亚基。用共聚焦显微镜观察猕猴和兔视网膜切片。所有II无长突细胞被选择性标记为calretinin，而兔AI细胞被标记为5-HT摄取。因此，这些标记和GluR亚基的双重和三重标记是可能的。电镜下用免疫细胞化学和双标记法显示突触中GluRs的表达。我们还研究了两个突触后密度蛋白PSD-95和谷氨酸受体相互作用蛋白（GRIP）的突触定位。我们发现，AII无长突细胞表达的AMPA受体亚基GluR 2/3和GluR 4在RB细胞二分体，它们聚集在一起与PSD-95。相比之下，AI无长突细胞表达似乎与红藻氨酸受体亚基相关的δ 1/2亚基，并与GRIP聚集在一起。因此，RB细胞二分体是启动两个功能和分子上不同的途径的突触：基于AMPA受体的“通过传导”途径和由δ 1/2亚基和红藻氨酸受体的组合介导的调节途径。
Rod bipolar (RB) cells of the mammalian retina release glutamate in a graded, light-dependent fashion from 20 to 40 ribbon synapses (dyads). At the dyads, two classes of amacrine cells, the AI and AII cells, are the postsynaptic partners. We examined the glutamate receptors (GluRs) that are expressed by AI and AII cells using immunocytochemistry with specific antibodies against GluR subunits. Sections of macaque monkey and rabbit retina were examined by confocal microscopy. AII amacrine cells were selectively labeled for calretinin, and AI cells in rabbits were labeled for 5-HT uptake. Thus, double- and triple-labeling for these markers and GluR subunits was possible. Electron microscopy using postembedding immunocytochemistry and double-labeling was applied to show the synaptic expression of GluRs. We also studied the synaptic localization of the two postsynaptic density proteins PSD-95 and glutamate receptor-interacting protein (GRIP). We found that AII amacrine cells express the AMPA receptor subunits GluR2/3 and GluR4 at the RB cell dyads, and they are clustered together with PSD-95. In contrast, AI amacrine cells express the delta1/2 subunits that appear to be associated with kainate receptor subunits and to be clustered together with GRIP. The RB cell dyad is therefore a synapse that initiates two functionally and molecularly distinct pathways: a "through conducting" pathway based on AMPA receptors and a modulatory pathway mediated by a combination of delta1/2 subunits and kainate receptors.