An alternative pathway for rod signals in the rodent retina:: Rod photoreceptors, cone bipolar cells, and the localization of glutamate receptors
An alternative pathway for rod signals in the rodent retina:: Rod photoreceptors, cone bipolar cells, and the localization of glutamate receptors
复制标题
DOI：
10.1073/pnas.96.24.14130
复制
发表时间：
1999-11-23
影响因子：
11.1
通讯作者：
Brandstätter, JH
中科院分区：
文献类型：
--
作者：
Hack, I;Peichl, L;Brandstätter, JH
在哺乳动物的视网膜中，时空和色彩信息进行广泛的处理。通过视网膜传输信号的一项关键原则是并行处理。其中两个平行路径是传输光信号和暗信号的开通道和关通道。这个双系统是在外丛状层中创建的，是视网膜信号传输的第一个中继站。光感受器将谷氨酸释放到 ON 型和 OFF 型双极细胞上，这些细胞在功能上通过不同类型谷氨酸受体（即离子型和代谢型谷氨酸受体）的突触后表达来区分。在当前概念中，辐射光感受器仅与视杆双极细胞（ON型）连接，视锥光感受器仅与视锥双极细胞（ON型和OFF型）连接。我们通过免疫电子显微镜和连续切片重建研究了（RS）-α-氨基羟基-5-甲基-4-异恶唑丙酸（AMPA）谷氨酸受体亚基在啮齿动物视网膜原丛状层突触处的分布。我们报告了视网膜中的非经典突触接触和杆状信号的替代途径。视杆光感受器与假定的离锥体双极细胞形成突触接触，这些细胞在树突上表达 AMPA 谷氨酸受体亚基 GluR1 和 GluR2。因此，在小鼠和大鼠的视网膜中，存在视杆信号的替代途径，其中视杆光感受器绕过视杆双极细胞并通过保存AMPA谷氨酸受体的离子型信号直接激发离视锥双极细胞。
In the mammalian retina, extensive processing of spatiotemporal and chromatic information occurs. One key principle in signal transfer through the retina is parallel processing. Two of these parallel pathways are the ON- and OFF-channels transmitting light and dark signals. This dual system is created in the outer plexiform layer, the first relay station in retinal signal transfer. Photoreceptors release glutamate onto ON- and OFF-type bipolar cells, which are functionally distinguished by their postsynaptic expression of different types of glutamate receptors, namely ionotropic and metabotropic glutamate receptors. in the current concept, rad photoreceptors connect only to rod bipolar cells (ON-type) and cone photoreceptors connect only to cone bipolar cells (ON- and OFF-type). We have studied the distribution of (RS)-alpha-aminoJhydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor subunits at the synapses in the auter plexiform layer of the rodent retina by immunoelectron microscopy and serial section reconstruction. We report a non-classical synaptic contact and an alternative pathway for rod signals in the retina. Rod photoreceptors made synaptic contact with putative OFF-cone bipolar cells that expressed the AMPA glutamate receptor subunits GluR1 and GluR2 on their dendrites. Thus, in the retina of mouse and rat, an alternative pathway for rod signals exists, where rod photoreceptors bypass the rod bipolar cell and directly excite OFF-cone bipolar cells through an ionotropic sign conserving AMPA glutamate receptor.