Retinal horizontal cells use different synaptic sites for global feedforward and local feedback signaling.
Retinal horizontal cells use different synaptic sites for global feedforward and local feedback signaling.
复制标题
DOI：
10.1016/j.cub.2021.11.055
复制
发表时间：
2022-02-07
期刊：
影响因子：
--
通讯作者：
Schubert T
中科院分区：
文献类型：
--
作者：
Behrens C;Yadav SC;Korympidou MM;Zhang Y;Haverkamp S;Irsen S;Schaedler A;Lu X;Liu Z;Lause J;St-Pierre F;Franke K;Vlasits A;Dedek K;Smith RG;Euler T;Berens P;Schubert T
在哺乳动物视网膜的外丛状层（OPL）中，视锥光感受器（视锥）向十几种类型的视锥双极细胞（CBC）提供输入。在小鼠中，这种传输由单个水平细胞（HC）类型调制。HC在其横向耦合的网络内执行全局信令，但也提供局部的、视锥特定的反馈。然而，它是未知的HC如何提供局部反馈锥在同一时间作为全球前向信号CBCs和潜在的突触位于何处。为了评估HC如何同时执行不同的信号模式，我们重建了5个HC的树突树以及锥轴突终末和CBC树突在一个连续的块面电子显微镜体积，并分析了它们的连接。除了细HC树突尖端内陷锥体轴突终末，我们还确定了“灯泡”，短节的增加树突直径的初级树突的HC。这些球位于锥体轴突终末基底下方的OPL层中，并与其他HC和CBCs接触。我们的免疫标记，电子显微镜和谷氨酸成像的结果表明，HC灯泡代表GABA能突触，不接受任何直接的光感受器输入。总之，我们的数据表明，存在两个突触层在小鼠OPL，空间分离锥特异性反馈和前馈信号到CBCs。HC树突分支的生物物理模型和电压成像支持这样的假设：突触接触的这种空间排列允许HC同时进行局部反馈和全局前馈信号传导。在哺乳动物视网膜中，水平细胞如何同时向光感受器提供局部反馈和向双极细胞提供全局前向信号还不清楚。Behrens等人鉴定了小鼠视网膜外层的第二个突触层，在空间上将视锥光感受器特异性反馈和前馈信号传递到双极细胞。
In the outer plexiform layer (OPL) of the mammalian retina, cone photoreceptors (cones) provide input to more than a dozen types of cone bipolar cell (CBC). In the mouse, this transmission is modulated by a single horizontal cell (HC) type. HCs perform global signaling within their laterally coupled network, but also provide local, cone-specific feedback. However, it is unknown how HCs provide local feedback to cones at the same time as global forward signaling to CBCs and where the underlying synapses are located. To assess how HCs simultaneously perform different modes of signaling, we reconstructed the dendritic trees of five HCs as well as cone axon terminals and CBC dendrites in a serial block-face electron microscopy volume and analyzed their connectivity. In addition to the fine HC dendritic tips invaginating cone axon terminals, we also identified “bulbs”, short segments of increased dendritic diameter on the primary dendrites of HCs. These bulbs are in a OPL stratum well below the cone axon terminal base and make contacts with other HCs and CBCs. Our results from immunolabeling, electron microscopy and glutamate imaging suggest that HC bulbs represent GABAergic synapses that do not receive any direct photoreceptor input. Together, our data suggests the existence of two synaptic strata in the mouse OPL, spatially separating cone-specific feedback and feedforward signaling to CBCs. A biophysical model of a HC dendritic branch and voltage imaging support the hypothesis that this spatial arrangement of synaptic contacts allows for simultaneous local feedback and global feedforward signaling by HCs. In the mammalian retina, it is unclear how horizontal cells provide both local feedback to photoreceptors and global forward signaling to bipolar cells simultaneously. Behrens et al. identify a second synaptic stratum in the outer mouse retina, spatially separating cone photoreceptor-specific feedback and feedforward signaling to bipolar cells.
登录
查看更多内容
DOI：
10.1085/jgp.67.6.639
发表时间：
1976-06
期刊：
The Journal of general physiology
影响因子：
--
作者：
Miller RF;Dacheux RF
通讯作者：
Dacheux RF
影响因子：
16.2
作者：
DeVries, Steven H.;Li, Wei;Saszik, Shannon
通讯作者：
Saszik, Shannon
影响因子：
2.5
作者：
Hartveit, E
通讯作者：
Hartveit, E
影响因子：
7.7
作者：
Behrens, Christian;Schubert, Timm;Berens, Philipp
通讯作者：
Berens, Philipp
影响因子：
9.8
作者：
Grove, James C. R.;Hirano, Arlene A.;Barnes, Steven
通讯作者：
Barnes, Steven