Calcium Signaling in Suprachiasmatic Nucleus Neurons

视交叉上核神经元中的钙信号传导

• 批准号: 8197673
• 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/8197673
• 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; public health relevance; 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）：通过改变两个时钟基因的表达PER1和PER2的表达，从而吸引了位于上核（SCN）神经元中的昼夜节律时钟，从而确保生理过程在适当的时间发生。光信息通过视网膜丘脑图（RHT）传播到SCN，该视网膜座（RHT）由光敏感性的视网膜神经节细胞组成，这些视网膜神经节细胞含有含有SCN神经元突触的Phopopigment Melanopsin。 SCN的RHT输入启动了细胞内信号传导级联，该级联最终导致时钟基因的表达改变，但特定途径的理解仍然很差。在一个模型中，RHT输入激活了电压依赖性Ca2+通道，从而触发了从细胞内存储中释放Ca2+，这可能是通过一氧化氮信号传导介导的。但是，这些发现尚未直接与改变的时钟基因表达联系在一起。在本提案中，我们将利用一种新的动物模型，该模型可以研究单个SCN神经元中PER1的活动依赖性诱导。我们研究的总体目标是了解调节上核神经元的光学夹带的信号转导途径。根据当前资金期间获得的数据，我们假设Ca2+主要通过L型电压依赖性Ca2+通道进入SCN神经元，这在动作电位发射过程中，触发性谷氨酸能或兴奋性GABAERGIC突触传递诱导的触发触发性触发触发了PER1基因表达。在昼夜节日的不同部分，四个具体目标将研究SCN神经元中Ca2+和PER1基因表达的调节。我们将使用Ca2+成像和单细胞电生理记录方法的创新组合，用于从转基因小鼠（PER1：VENUS）制备的SCN神经元，这些方法表达由PER1启动子驱动的荧光蛋白质金星。这些方法将使我们能够监视Ca2+浓度和膜电位的变化，同时记录单个SCN神经元中的PER1表达。通过这项研究，我们期望确定光夹带途径的组成步骤，更普遍地，可以更好地理解调节基因表达中活性依赖性变化的机制。 公共卫生相关性：鉴于人类在我们复杂社会中人类的围绕时钟活动的增加，重要的是要了解昼夜节律和环境之间的奇异性如何有助于增加对各种疾病的脆弱性，并确定导致缓解或纠正的机制和策略。