Regulation of Neurotransmission in the Retina

描述(申请人提供)：本提案的目标是描述一种基本的钙信号机制，该机制调节细胞内对光刺激的长期适应性反应，当异常时，导致光感受器退化。我们将确定细胞内钙库的耗尽如何通过光感受器质膜上由钙库操作的钙通道来触发钙内流。将确定储存操作通道的分子异构体，并确定它们在调节自发突触反应和光诱发反应的幅度和频率中的作用。通过商店操作的通道的病理性钙内流杀死光感受器的机制将在遗传性视网膜变性的小鼠模型系统和缺乏商店操作(TRPC)通道亚型的小鼠中表征。 提出了两个具体目标： 具体目标1：表征钙离子通道进入在光感受器钙稳态和神经传递中的作用 特定目标2：确定视网膜中瞬时受体电位通道(TRPC)的表达，并确定它们在储存操作的钙内流和视觉信号中的作用 在分离细胞、视网膜切片和TRPC基因敲除小鼠上进行的实验将结合高分辨率钙成像技术与膜片钳电生理学、免疫细胞化学、RT-PCR、基因芯片和RNAi技术。钙库的耗尽和功能失调的钙内流杀死了感光器。因此，拟议的研究将帮助我们了解光感受器如何调节其钙水平以维持最佳的信号范围，也将帮助我们识别潜在的候选细胞靶点，用于视网膜疾病期间的治疗干预。

DESCRIPTION (provided by applicant): The objective of this proposal is to characterize a fundamental calcium signaling mechanism that regulates long lasting intracellular adaptive responses to light stimulation and, when abnormal, causes photoreceptor degeneration. We will determine how depletion of intracellular calcium stores triggers calcium influx through store-operated calcium channels in the plasma membrane of photoreceptors. The molecular isoforms of store-operated channels will be identified and their role in regulating the amplitude and frequency of spontaneous synaptic responses and light-evoked responses, determined. The mechanisms, through which pathological calcium influx through store-operated channels kills photoreceptors will be characterized in mouse model systems for inherited retinal degeneration and in mice lacking store-operated (TRPC) channel isoforms. Two Specific Aims are proposed: Specific Aim 1: To characterize the roles of store-operated calcium channel entry in photoreceptor calcium homeostasis and neurotransmission Specific Aim 2: To identify expression of transient receptor potential channels (TRPCs) in the retina, and to determine their role in store-operated calcium entry and visual signaling The experiments in isolated cells, retinal slices and TRPC knockout mice will combine high-resolution calcium imaging techniques with patch clamp electrophysiology, immunocytochemistry, RT-PCR, gene chip and RNAi technology. Depletion of calcium stores and dysfunctional calcium influx kill photoreceptors. Thus, the proposed studies will help us understand how photoreceptors adjust their calcium levels to maintain optimal signaling range and will also help us identify potential candidate cellular targets for therapeutic interventions during retinal disease.