ROD AND CONE SIGNALING PATHWAYS IN MAMMALIAN RETINA

描述(申请人提供)：在这个竞争性的更新申请中，我们建议继续并扩大我们在暗适应小鼠视网膜的双极细胞(BC)、无长突细胞(AC)和神经节细胞(GC)水平上的视杆细胞和视锥细胞信号通路的研究。我们将集中精力研究BC和AC突触回路介导杆状突触、M视锥和M/S视锥信号向三种类型的α神经节细胞的传递，并确定甘氨酸能和GABA能AC是如何通过AC视锥BC GC反馈通路和AC GC前馈突触来调节αGCs中的光诱发信号的。有三个具体的目的：(1)将三个字母GC回路中的生理BC类型与解剖BC类型联系起来，并确定杆/锥与BCS之间以及BCS与αGC之间可能的突触接触：(2)通过分析野生型、Tra-/-和Gnat2cplf3小鼠BCS和αGC的光诱发阳离子电流(IC)，确定杆/锥介导的BCS和αGC的相对强度和信号在三个αGC回路中的整合机制；(3)用双标记和双电压钳技术测定甘氨酸能和GABA能AC对αGCs光诱导抑制和BC突触输入的相对贡献，以及GABA能AC和AlphaGC之间可能的突触连接。我们研究的目标是了解哺乳动物视网膜网络如何处理视觉图像，这是NEI的一个基本研究重点，并提供有关单个视网膜神经元和突触在疾病状态下如何功能障碍的关键信息，例如先天性静止性夜盲和青光眼，这是NEI的翻译研究重点。此外，了解健康和疾病眼睛中特定的哺乳动物视网膜回路将有助于开发治疗视网膜疾病的新基因/药物疗法，如视网膜色素变性和青光眼，以及设计有效的视网膜假体设备。

DESCRIPTION (provided by applicant): In this competing renewal application, we propose to continue and extend our investigations on rod and cone signaling pathways at the bipolar cell (BC), amacrine cell (AC) and ganglion cell (GC) levels in the dark-adapted mouse retina. We will focus our efforts to study the BC and AC synaptic circuitries mediating rod, M-cone and M/S-cone signal transmission to three types of alpha ganglion cells (alphaGCs), and to determine how glycinergic and GABAergic ACs regulate light-evoked signals in alphaGCs via the AC cone BC GC feedback pathways and the AC GC feedforward synapses. There are three specific aims: (1) to correlate physiological BC types with anatomical BC types in the three alphaGC circuitries and to identify possible synaptic contacts between rods/cones and BCs and between BCs and alphaGCs; (2) to determine the relative strengths of rod- and cone-mediated inputs to BCs and alphaGCs and mechanisms of signal integration in the 3 alphaGC circuitries by analyzing BCs' and alphaGCs' light-evoked cation currents ( IC) in wildtype, Tralpha-/- and Gnat2cplf3 mice; and (3) to determine relative glycinergic and GABAergic AC contributions to alphaGCs' light-evoked inhibitory and BC synaptic inputs and possible synaptic connectivity between individual GABAergic ACs and alphaGCs by double label and dual voltage clamp techniques. The goal of our research is to understand how mammalian retinal networks process visual images, a basic research priority of the NEI, and to provide crucial information on how individual retinal neurons and synapses dysfunction in disease states, such as congenital stationary night blindness and glaucoma, a translational research priority of the NEI. Moreover, knowledge of specific mammalian retinal circuitries in healthy and diseased eyes will be useful for developing new gene/drug therapies for retinal disorders, such as retinitis pigmentosa and glaucoma, as well as for designing effective retinal prosthetic devices.