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）：该提案的总体目的是检查内部钙（Ca2+）在神经终端中的作用。众所周知，神经递质和激素的释放紧密耦合到自由细胞内Ca2+浓度中的升高。尽管Ca2+通过电压门控Ca2+通道的涌入无疑是CA2+的非常重要的来源，而CA2+从内部商店释放可能会为此过程提供另一个重要的Ca2+来源。直到最近，这些细胞内商店吸引了相对较少的关注，并且它们在神经末端的存在是有争议的。最近的工作表明，在神经元制剂中可以看到高度局部的Ca2+释放事件，例如CA2+肌肉的火花。在神经型物理末端，这些Ca2+释放事件似乎是从ryanodine敏感的细胞内Ca2+池散发出来的，而去极化刺激会导致其频率增加。尽管有所有这些信息，但释放的Ca2+的来源以及该现象的生理作用尚不清楚。初步证据表明，这些CA2+释放事件可以代表来自水泡存储的Ca2+的动员。如果是这样，在胞吐作用的精确位置中的局部Ca2+释放应调节释放。我们的目标是确定这些ryanodine敏感的Ca2+释放事件的来源，并阐明这种动员Ca2+对神经肽分泌的生理作用。为此，我们首次能够开发一种能够检测来自单个神经终端的定量释放事件的技术。这种安培技术使我们能够同时执行CA2+成像，并监视发射机从单个隔离神经末端的定义区域释放。该项目旨在增加当前对神经型末端生理学的知识，并且更普遍地将对细胞内钙和大型密集核心颗粒状融合发生在中枢神经系统中所起的作用提供更完整的理解。因此，这些知识可能被证明对于理解和治疗突触病理很重要。公共卫生相关性：大脑内部及其目标的通信是通过在神经终端释放发射器，并且已知这种释放取决于细胞外钙的进入以及随后的宁静升高。我们最近表明，神经末端具有细胞内钙存储，在此提案中，我们利用新型技术来确定这些内血存储是什么，以及它们是否可以调节神经末端发射机的释放。这些知识可能对理解和治疗突触疾病非常重要，例如伊顿 - 兰伯特综合征和肌萎缩性侧面硬化症，以及阿尔茨海默氏病和神经元衰老。