Calcium Signaling in Suprachiasmatic Nucleus Neurons

视交叉上核神经元中的钙信号传导

• 批准号: 8059339
• 负责人: Charles N Allen
• 金额: $ 33.6万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-01 至 2014-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8059339
• 关键词: Action Potentials; Animal Model; Calcium Signaling; Cells; Circadian Rhythms; Complex; Coupled; Data; Disease; Ensure; Environment; Funding; GABA Receptor; Gene Expression; Genes; Glutamate Receptor; Glutamates; Goals; Human Activities; Image; Individual; Light; Mediating; Membrane Potentials; Methods; Modeling; Monitor; Neurons; Nitric Oxide; Pathway interactions; Physiological Processes; Proteins; Regulation; Research; Retinal Ganglion Cells; Role; Ryanodine; Signal Transduction; Signal Transduction Pathway; Societies; Synapses; Synaptic Transmission; Testing; Time; Transgenic Mice; Venus; base; channel blockers; circadian pacemaker; gamma-Aminobutyric Acid; innovation; light entrainment; melanopsin; neurotransmission; promoter; research study; suprachiasmatic nucleus; tool; voltage

DESCRIPTION (provided by applicant): Light entrains the circadian clock located in suprachiasmatic nucleus (SCN) neurons by altering the expression of two clock genes, Per1 and Per2, thus ensuring that physiological processes occur at the appropriate time of day. Light information is transmitted to the SCN via the retinohypothalamic tract (RHT), composed of light-sensitive retinal ganglion cells containing the photopigment melanopsin that synapse on SCN neurons. RHT input to the SCN initiates an intracellular signaling cascade that ultimately leads to altered expression of clock genes, but the specific pathways remain poorly understood. In one model, RHT input activates voltage-dependent Ca2+ channels, triggering release of Ca2+ from intracellular stores, possibly mediated through nitric oxide signaling. However, these findings as yet have not been tied directly to altered clock gene expression. In the present proposal, we will take advantage of a new animal model that makes it possible to study activity-dependent induction of Per1 in individual SCN neurons. The overall goal of our research is to understand the signal transduction pathways regulating photic entrainment of suprachiasmatic nucleus neurons. Based on the data obtained during the current funding period, we hypothesize that Ca2+ entering SCN neurons primarily through L-type voltage-dependent Ca2+ channels during action potential firing triggered by excitatory glutamatergic or excitatory GABAergic synaptic transmission induces Per1 gene expression. Four Specific Aims will study the regulation of Ca2+ and Per1 gene expression in SCN neurons during different portions of the circadian day. We will use an innovative combination of Ca2+ imaging and single cell electrophysiological recording methods applied to SCN neurons prepared from transgenic mice (Per1:Venus) expressing the fluorescent protein Venus driven by the Per1 promoter. These methods will allow us to monitor changes in Ca2+ concentration and membrane potential while simultaneously recording Per1 expression in individual SCN neurons. Through this research, we expect to identify the component steps of the light entrainment pathway, and more generally, to provide a better understanding of the mechanisms regulating activity- dependent changes in gene expression. PUBLIC HEALTH RELEVANCE: Given the increasing around the clock activity of humans in our complex society it is important to understand how desynchrony between circadian clocks and the environment contribute to an increased vulnerability to a variety of diseases and to identify the mechanisms and strategies leading to mitigation or correction.

描述（由申请人提供）：光通过改变两个时钟基因 Per1 和 Per2 的表达来控制位于视交叉上核 (SCN) 神经元的生物钟，从而确保生理过程在一天中的适当时间发生。光信息通过视网膜下丘脑束 (RHT) 传输到 SCN，该束由感光视网膜神经节细胞组成，含有与 SCN 神经元突触的感光色素黑视蛋白。 RHT 输入至 SCN 启动细胞内信号级联反应，最终导致时钟基因表达的改变，但具体途径仍知之甚少。在一种模型中，RHT 输入激活电压依赖性 Ca2+ 通道，触发细胞内储存的 Ca2+ 释放，这可能是通过一氧化氮信号传导介导的。然而，这些发现尚未与时钟基因表达的改变直接相关。在目前的提案中，我们将利用一种新的动物模型，使研究单个 SCN 神经元中 Per1 的活动依赖性诱导成为可能。我们研究的总体目标是了解调节视交叉上核神经元光夹带的信号转导途径。根据本次资助期间获得的数据，我们假设在兴奋性谷氨酸或兴奋性 GABA 突触传递触发动作电位放电期间，Ca2+ 主要通过 L 型电压依赖性 Ca2+ 通道进入 SCN 神经元，从而诱导 Per1 基因表达。四个具体目标将研究昼夜节律不同时段 SCN 神经元中 Ca2+ 和 Per1 基因表达的调节。我们将采用 Ca2+ 成像和单细胞电生理记录方法的创新组合，应用于由表达由 Per1 启动子驱动的荧光蛋白 Venus 的转基因小鼠 (Per1:Venus) 制备的 SCN 神经元。这些方法将使我们能够监测 Ca2+ 浓度和膜电位的变化，同时记录单个 SCN 神经元中 Per1 的表达。通过这项研究，我们期望确定光夹带途径的组成步骤，更广泛地说，提供对调节基因表达活动依赖性变化的机制的更好理解。 公共卫生相关性：鉴于人类在复杂的社会中不断增加的昼夜活动，了解生物钟与环境之间的不同步如何导致各种疾病的脆弱性增加，并确定导致缓解的机制和策略非常重要或修正。