Peptide Release Regulated by Ca2+ from Neurosecretory Granules

神经分泌颗粒中 Ca2 调节的肽释放

• 批准号: 7766209
• 负责人: JOSE R LEMOS
• 金额: $ 17.79万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-15 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7766209
• 关键词: Affect; Aging; Agonist; Alzheimer' s Disease; Amyotrophic Lateral Sclerosis; Area; Argipressin; Attention; Brain; Calcium; Cells; Communication; Coupled; Cytosol; Disease; Electric Capacitance; Electron Microscopy; Event; Exocytosis; Fluo-3; Fluorescence Microscopy; Frequencies; Goals; Hormones; Image; Individual; Kinetics; Knowledge; Lambert-Eaton Myasthenic Syndrome; Lipid Bilayers; Location; Measurement; Membrane; Monitor; Mus; Muscle; Nerve; Neuraxis; Neurons; Neuropeptides; Neurosecretory Granule; Neurotransmitters; Oxytocin; Pathology; Peptides; Physiological; Physiology; Play; Preparation; Process; Resolution; Role; Ryanodine; Ryanodine Receptor Calcium Release Channel; Ryanodine Receptors; Secretory Vesicles; Source; Stimulus; Synapses; Techniques; Time; Vesicle; Work; controlled release; extracellular; immunocytochemistry; neurotransmitter release; novel; peptide hormone; public health relevance; voltage

DESCRIPTION (provided by applicant): The overall aim of this proposal is to examine the role of internal calcium (Ca2+) stores in nerve terminals. It is well known that the release of neurotransmitters and hormones is tightly coupled to rises in the free intracellular Ca2+ concentration. While the influx of Ca2+ through voltage-gated Ca2+ channels is undoubtedly a very important source of Ca2+ affecting release, Ca2+ release from internal stores may provide another important source of Ca2+ for this process. Until recently these intracellular stores have attracted relatively little attention, and their very existence in nerve terminals was controversial. Recent work has shown that highly localized Ca2+ release events, like Ca2+ sparks of the muscle, can be seen in neuronal preparations. In neurohypophysial terminals, these Ca2+ release events appear to emanate from a ryanodine-sensitive intracellular Ca2+ pool, and depolarizing stimuli induce an increase in their frequency. In spite of all this information, the source of the released Ca2+, and a physiological role for this phenomenon, is unknown. Preliminary evidence suggests that these Ca2+ release events could represent mobilization of Ca2+ from vesicular stores. If so, localized Ca2+ release in the precise location of exocytosis should modulate release. It is our goal to determine the source of these ryanodine sensitive Ca2+ release events in neurohypophysial terminals, and to elucidate the physiological role of this mobilization of Ca2+ on neuropeptide secretion. To accomplish this we have been able to develop, for the first time, a technique capable of detecting quantal release events from individual nerve terminals. This amperometric technique allows us to simultaneously perform Ca2+ imaging and monitor transmitter release from a defined area of a single isolated nerve terminal. This project aims to add to the current body of knowledge of the physiology of the neurohypophysial terminals, and, more generally, will provide a more complete understanding of the role played by intracellular calcium and of the mechanism by which large dense core granular fusion occurs in the Central Nervous System. This knowledge could thus prove to be important for the understanding and treatment of synaptic pathologies. PUBLIC HEALTH RELEVANCE: Communication both within the brain and with its targets is via release of transmitters at nerve terminals, and such release is known to be dependent on the entry of extracellular calcium and the subsequent elevation of intraterminal calcium. We have recently shown that nerve terminals have intracellular calcium stores and in this proposal we utilize novel techniques to determine what are these intraterminal stores and whether they can regulate the release of transmitters from nerve terminals. This knowledge could prove to be important for the understanding and treatment of synaptic diseases such Eaton-Lambert Syndrome and Amyotrophic Lateral Sclerosis, as well as Alzheimer's disease and neuronal aging.

描述（由申请人提供）：本提案的总体目标是研究神经末梢内部钙（Ca2+）储存的作用。众所周知，神经递质和激素的释放与细胞内游离Ca2+浓度的升高密切相关。虽然Ca2+通过电压门控Ca2+通道的内流无疑是Ca2+影响释放的一个非常重要的来源，但内部储存的Ca2+释放可能为这一过程提供另一个重要的Ca2+来源。直到最近，这些细胞内的储存才引起了相对较少的关注，它们在神经末梢的存在是有争议的。最近的研究表明，高度局部的Ca2+释放事件，如肌肉的Ca2+火花，可以在神经元准备中看到。在神经垂体末梢，这些Ca2+释放事件似乎来自于对红嘌呤敏感的细胞内Ca2+池，去极化刺激诱导其频率增加。尽管有这些信息，Ca2+释放的来源和这一现象的生理作用，是未知的。初步证据表明，这些Ca2+释放事件可能代表Ca2+从囊泡储存的动员。如果是这样，在胞吐的精确位置的局部Ca2+释放应该调节释放。我们的目标是确定神经垂体末梢这些对ryanodine敏感的Ca2+释放事件的来源，并阐明Ca2+动员对神经肽分泌的生理作用。为了实现这一目标，我们已经能够首次开发出一种能够检测单个神经末梢量子释放事件的技术。这种安培技术允许我们同时进行Ca2+成像和监测从一个孤立的神经末梢的一个特定区域释放的递质。该项目旨在增加当前对神经垂体末梢生理学的知识体系，更广泛地说，将提供对细胞内钙所起作用的更完整的理解，以及在中枢神经系统中发生大致密核颗粒融合的机制。因此，这一知识对于理解和治疗突触病理是很重要的。公共卫生相关性：脑内及其靶标之间的通信是通过神经末梢的递质释放来实现的，已知这种释放依赖于细胞外钙的进入和随后的端内钙的升高。我们最近的研究表明，神经末梢有细胞内钙储存，在这个建议中，我们利用新技术来确定这些终端内钙储存是什么，以及它们是否可以调节神经末梢的递质释放。这些知识对于理解和治疗突触疾病，如伊顿-兰伯特综合征和肌萎缩性侧索硬化症，以及阿尔茨海默病和神经元衰老是非常重要的。