Dissecting Mechanisms of Striatal Acetylcholine Transmission in the Vertebrate Brain

解析脊椎动物大脑中纹状体乙酰胆碱传输的机制

• 批准号: 10534406
• 负责人: Kathleen Allison Beeson
• 金额: $ 6.97万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10534406
• 关键词: Acetylcholine; Affect; Area; Axon; Basal Ganglia; Behavior; Brain; Calcium; Calcium Channel; Cholinergic Receptors; Complex; Corpus striatum structure; Data; Disease; Distant; Dopamine; Electrophysiology (science); Elements; Enzymes; Exocytosis; Functional Imaging; Genes; Genetic; Goals; Health; Interneurons; Learning; Locomotion; Measurement; Measures; Messenger RNA; Microscopy; Modeling; Molecular; Morphology; Motivation; Mus; Nerve; Nervous System Physiology; Neuraxis; Neuromodulator; Neuromuscular Junction; Neurons; Nicotinic Receptors; Phase; Phospholipids; Proteins; Rewards; Signal Transduction; Site; Slice; Structure; Synapses; System; Testing; Tissue imaging; Tissues; Transcript; Transgenic Organisms; Varicosity; Vesicle; Work; base; brain volume; cholinergic; conditional knockout; density; esterase; fluorescence imaging; insight; mouse genetics; nano; neuroregulation; presynaptic; receptor; scaffold; secretory protein; sensor; social cognition; spatial relationship; synaptotagmin I; tool; transmission process; vesicular release

PROJECT SUMMARY Acetylcholine critically controls complex neurological functions through its modulation of brain circuits. In contrast to the well-studied mechanisms of acetylcholine signaling at the neuromuscular junction, its transmission modes and mechanisms in the vertebrate central nervous system are not well understood. In the striatum, acetylcholine exerts rapid and powerful control over local dopaminergic activity. Together, these neuromodulators regulate a variety of important behaviors, including motivation and reward-related learning. Because acetylcholine is rapidly degraded after it is released in striatal tissues, the fidelity of acetylcholine to dopamine signaling must involve either tight spatial relationships between release sites and receptors, and/or fast transmission. However, neuromodulator signaling is classically modeled as occurring through volume transmission, involving dispersed, non-specific release as opposed to synaptic, point-to-point signaling – a concept that remains to be proven. Furthermore, the molecular mechanisms underlying striatal acetylcholine signaling remain elusive. I hypothesize that sparse cholinergic terminals require molecular elements for highly synchronous acetylcholine release. In this scenario, rapid and precise vesicle release could produce a synchronous wave of high-concentration acetylcholine, which might allow even distant receptors to sense this signal with potency. To test this hypothesis, I propose to examine the morphological and molecular substrate of striatal acetylcholine transmission in two aims. First, I will dissect the structure of acetylcholine to dopamine signaling in the striatum, including the presence of secretory machinery in acetylcholine nerve terminals and their apposition to acetylcholine receptors on dopamine axons, using superresolution microscopy. In a second aim, I will functionally test whether acetylcholine release onto dopamine axons requires secretory proteins that are predestined to generate fast and precise release, enabling phasic acetylcholine transmission. Additionally, I will determine how this transmission mode impacts subsequent dopamine signaling. To do this, I will use genetic tools paired with simultaneous imaging of fluorescent acetylcholine sensors and amperometric dopamine measurements in striatal slices. Together, these findings will inform our fundamental understanding of cholinergic to dopaminergic signaling in the striatum, including the identification of important genes that regulate acetylcholine transmission. This molecular-level understanding will ultimately be important to better understand brain function and disease.

项目摘要 乙酰胆碱通过其对大脑回路的调节来控制复杂的神经功能。在 与神经肌肉接头处乙酰胆碱信号传导的充分研究机制相反， 脊椎动物中枢神经系统中的传递模式和机制还没有很好地理解。在 在纹状体中，乙酰胆碱对局部多巴胺能活性发挥快速和强有力的控制。所有这些 神经调质调节各种重要行为，包括动机和奖励相关学习。 由于乙酰胆碱在纹状体组织中释放后迅速降解，因此乙酰胆碱对 多巴胺信号传导必须涉及释放位点和受体之间的紧密空间关系，和/或 快速传输。然而，神经调质信号传导被经典地建模为通过体积发生， 传递，涉及分散的，非特异性的释放，而不是突触，点对点的信号传递- a 这个概念还有待证实。此外，纹状体乙酰胆碱的分子机制 信号仍然难以捉摸。我推测，稀疏的胆碱能末梢需要分子元件才能高度表达胆碱能。 同步乙酰胆碱释放。在这种情况下，快速和精确的囊泡释放可以产生一个 高浓度乙酰胆碱的同步波，这可能允许甚至遥远的受体感受到这一点 信号强度。 为了验证这一假设，我建议检查纹状体的形态学和分子基质， 乙酰胆碱传递有两个目的。首先，我将剖析乙酰胆碱的结构， 在纹状体中，包括乙酰胆碱神经末梢中分泌机制的存在及其 并置到多巴胺轴突上的乙酰胆碱受体，使用超分辨率显微镜。第二个目标，我 将在功能上测试乙酰胆碱释放到多巴胺轴突是否需要分泌蛋白， 注定产生快速和精确的释放，使阶段性乙酰胆碱传输。另外，我将 确定这种传输模式如何影响随后的多巴胺信号。为了做到这一点，我将使用遗传 与荧光乙酰胆碱传感器和电流多巴胺同时成像的工具配对 纹状体切片中的测量。总之，这些发现将告知我们对以下问题的基本理解： 纹状体中的胆碱能到多巴胺能信号传导，包括鉴定重要基因， 调节乙酰胆碱传递。这种分子水平的理解最终将对更好地 了解大脑功能和疾病。