Glycine subunit specific inhibition and ganglion cell visual responses

甘氨酸亚基特异性抑制和神经节细胞视觉反应

• 批准号: 10622520
• 负责人: RONALD G GREGG
• 金额: $ 46.56万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10622520
• 关键词: Address; Amacrine Cells; Biological Assay; Brain Stem; Categories; Cells; Central Nervous System; Color; Cre driver; Data; Electrophysiology (science); Feedback; Glycine; Glycine Receptors; Goals; Individual; Injections; Interneurons; Kinetics; Knock-out; Knockout Mice; Light; Location; Masks; Mediating; Morphology; Mus; Neurotransmitters; Object Attachment; Output; Pharmacology; Process; Property; Publishing; Reaction Time; Reporter; Rest; Retina; Retinal Ganglion Cells; Role; Shapes; Signal Transduction; Size Perception; Spinal Cord; Stimulus; Stream; Structure; Strychnine; Synapses; System; Time; Vision; Visual; Visual Pathways; Work; biophysical properties; cell type; gamma-Aminobutyric Acid; ganglion cell; knock-down; novel; object motion; parallel processing; pharmacologic; postsynaptic; presynaptic; receptor; response; retrograde transport; small hairpin RNA; spatial vision; spatiotemporal; superior colliculus Corpora quadrigemina; synaptic inhibition; vector; visual control

Retinal ganglion cells (GCs) integrate excitatory and inhibitory inputs and perform computations that encode diverse features of the visual scene. The output of these functionally and morphologically diverse GCs establish visual signaling streams, maintained throughout the visual pathway. Ultimately, they create our perception of the size, shape and color of objects and their relationships in space. They establish relationships of objects in time, so that we know when it is stationary or moving, and when moving, its direction and velocity. To this end, there is a general division of labor between the retina's inhibitory neurotransmitter systems. GABA, and its receptors, modulate spatial vision, whereas glycine, and its receptors, modulate temporal vision. There are five glycine receptor subunits (one β and 4αs). The GlyRα subunits combine with a single β subunit to make functional receptors with diverse biophysical properties. Our work shows that all GCs expresses one or more GlyRα’s and the composition differs across GC type. We hypothesize that variety enhances the diversity of inhibitory functions across and within GC types and are used to encode the visual scene. However, the specific function of GlyRα subunits is almost completely unknown. We know that the responses (and transmitter release) of the GABA and glycinergic amacrine cells presynaptic to GCs are modulated by other glycinergic amacrine cell input. This means that until GlyRs can be selectively eliminated in GCs or ACs, we cannot disambiguate the role of direct GlyRα inhibition to GCs from GlyRα modulation in the upstream circuit that provides input to the GCs. We developed a novel AAV-shRNA knockdown (KD) approach that eliminates expression of individual G lyRα subunits in GCs, while leaving their upstream expression intact. We propose to use this approach to define the role of GlyRα direct inhibition in 7 identified GC types and by extension the role of isolated GABA inputs in those same GCs. In Aim 1 we ask if a single GlyRα, GlyRα1 expressed by the 4 functionally diverse αGCs modulates the same or different aspects of their visual responses. In aim 2 we ask if two different GlyRα subunits, expressed in the same GC, increase the diversity of inhibition to modulate different aspects of the visual response in a single GC type. We use electrophysiological assays to characterize the spiking responses of the GCs, underlying currents and the relationships between the kinetics of excitatory and inhibitory input with the postsynaptic response. This proposal addresses the novel concept: that diverse glycine subunit specific inhibition interacts with presynaptic inputs to controls visual computation.

视网膜神经节细胞（GC）整合兴奋性和抑制性输入，并执行编码 视觉场景的多样性。这些功能和形态多样的GC的输出建立了 视觉信号流，维持整个视觉通路。最终，他们创造了我们对 物体的大小、形状和颜色以及它们在空间中的关系。它们在时间上建立对象的关系， 我们知道它是静止的还是运动的，以及运动时的方向和速度。为此，有一个 视网膜的抑制性神经递质系统之间的一般分工。GABA及其受体， 调节空间视觉，而甘氨酸及其受体调节时间视觉。有五个甘氨酸 受体亚单位（1个β和4个α）。GlyRα亚基联合收割机与单个β亚基结合， 具有不同生物物理特性的受体。我们的工作表明，所有的GC都表达一个或多个GlyRα， 不同GC类型的组成不同。我们假设，多样性增强了抑制功能的多样性， 并且在GC类型内，并且用于对视觉场景进行编码。然而，GlyRα亚基的特定功能是 几乎完全未知。 我们知道，GABA和甘氨酸能无长突细胞的反应（和递质释放） 对GC的影响受其他甘氨酸能无长突细胞输入的调节。这意味着，直到GlyR可以被选择性地 在GC或AC中消除，我们不能从GlyRα调节中消除GlyRα对GC的直接抑制作用 在向GC提供输入的上游电路中。我们开发了一种新的AAV-shRNA敲低（KD） 这种方法消除了GC中单个G lyRα亚基的表达，同时保留其上游表达， 完整我们建议使用这种方法来确定GlyRα直接抑制在7种已鉴定的GC类型中的作用， 在这些相同的GC中，单独的GABA输入的作用。在目的1中，我们询问由4种功能不同的α GC表达的单个GlyRα，GlyRα1是否调节其视觉反应的相同或不同方面。在目标2中，我们问， 两种不同的GlyRα亚基，在同一GC中表达，增加了抑制的多样性，以调节不同的 在一个单一的GC类型的视觉响应方面。我们使用电生理分析来表征 GC的反应，潜在电流和兴奋性和抑制性动力学之间的关系 突触后反应的输入。 这一提议提出了新的概念：不同的甘氨酸亚基特异性抑制与 控制视觉计算的突触前输入。