Optical study of secretion in mammalian nerve terminals

哺乳动物神经末梢分泌的光学研究

• 批准号: 7895768
• 负责人: BRIAN Matthew SALZBERG
• 金额: $ 52.12万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-24 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7895768
• 关键词: Alzheimer' s Disease; Amplifiers; Argipressin; Atomic Force Microscopy; Biological Process; Blood Circulation; Calcium; Cell physiology; Cells; Chemicals; Coupled; Coupling; Cytoplasmic Granules; Dyes; Electron Microscopy; Equilibrium; Event; Exocytosis; Experimental Models; Extracellular Space; Fluorescence; Goals; Gold; Hormones; Human; Immune response; Impairment; Laboratories; Mammals; Measurement; Measures; Mechanics; Membrane; Mental Depression; Metabolism; Milk Ejection; Mitochondria; Modeling; Monitor; Mood Disorders; Mus; Nerve; Nervous system structure; Neurologic; Neurons; Neuropeptides; Optical Methods; Optics; Organ; Oxytocin; Parkinsonian Disorders; Peptides; Physiological; Physiology; Posterior Pituitary Gland; Process; Proteins; Regulation; Reproduction; Research; Resolution; Role; Scanning Probe Microscopes; Schizophrenia; Secretory Component; Secretory Vesicles; Sex Behavior; Signal Transduction; Slice; Source; Swelling; Synaptic Transmission; System; Techniques; Technology; Temperature; Time; Tissues; Transgenic Mice; Variant; Vertebrates; Water; base; blood pressure regulation; cell motility; coral; detector; fluorophore; information processing; insight; light scattering; magnocellular; millisecond; mouse model; nervous system disorder; neurotransmission; neurotransmitter release; novel; presynaptic; promoter; social cognition; tool; voltage

Secretion is one of the most ubiquitous of cellular processes. Indeed, it is central to such diverse biological functions as information processing, reproduction, motility, temperature regulation, metabolism, the immune response, and signal transduction. However, despite significant progress in identifying components of the macromolecular machinery essential for release of neurotransmitters and neuropeptides, the full elucidation of its mechanism(s) remains a challenge to cell physiologists. This is because direct observation of the intraterminal events that follow cellular excitation, but precede fusion of secretory vesicles, has proven extremely difficult. This proposal seeks to identify some of the cellular events that define calcium-dependent excitation coupling in mammalian peptidergic nerve terminals, and, in particular, to begin to understand the relationship between two novel millisecond time-resolved phenomena that are related to secretion, viz., light scattering changes from nerve terminals and the mechanical "spike" and the mechanical "dip" that follows it. Our experimental model is unique, the mouse neurohypophysis, a neurosecretory organ that comprises some 40,000,000 nerve terminals and secretory swellings, and that releases oxytocin and arginine vasopressin into the local circulation. Because no single technique is capable of providing the spatial and temporal resolution required for a comprehensive description of the secretory process, we will employ a multi-disciplinary approach that includes optical measurement of rapid changes in membrane voltage (using potentiometric dyes), in intraterminal calcium concentration, and in light scattering. Also, a modified atomic force microscope will be used to detect minute, but very rapid changes in nerve terminal volume. We will also use a set of novel techniques to begin to characterize, spatially and temporally, the changes in intraterminal Ca2+ ([Ca2+]i), during excitation-secretion (E-S) coupling in mammalian peptidergic nerve terminals. This will entail the identification of the sources and sinks of [Ca2+]i, and the elucidation of their roles before, during, and after exocytosis, with particular emphasis on the dense core granules and their possible role as intraterminal Ca2+-stores and Ca2+-amplifiers.

分泌是最普遍的细胞过程之一。事实上，这是核心， 各种生物功能，如信息处理，繁殖，运动， 温度调节、新陈代谢、免疫反应和信号转导。 然而，尽管在鉴定大分子的组分方面取得了重大进展， 神经递质和神经肽释放所必需的机制， 其机制的阐明仍然是细胞生理学家的挑战。这是 因为直接观察细胞兴奋后的终末内事件， 在分泌囊泡融合之前，已经证明是非常困难的。该提案寻求 为了识别一些定义钙依赖性兴奋耦合的细胞事件， 在哺乳动物的肽能神经末梢，特别是，开始了解 两个新毫秒时间分辨现象之间的关系， 与分泌有关，即，神经末梢的光散射发生变化， 机械“尖峰”和机械“下降”之后。我们的实验 模型是独特的，小鼠神经垂体，一个神经分泌器官，包括 大约40，000，000个神经末梢和分泌的分泌物，并释放催产素 和精氨酸加压素进入局部循环。因为没有一种技术 能够提供所需的空间和时间分辨率， 描述的分泌过程中，我们将采用多学科的方法， 包括膜电压快速变化的光学测量（使用 电位染料）、末端内钙浓度和光散射。还有， 一种改进的原子力显微镜将被用来检测微小的，但非常快速的 神经末梢体积的变化。我们还将使用一套新颖的技术来开始 在空间和时间上表征终末内Ca 2+（[Ca 2 +]i）的变化， 哺乳动物肽能神经末梢中的兴奋-分泌（E-S）偶联。这将 需要识别[Ca 2 +]i的源和汇，并阐明其 在胞吐作用之前，期间和之后的作用，特别强调致密核心 颗粒及其可能的作用，作为intraterminal Ca 2 +-商店和Ca 2 +-放大器。