Architecture and Function of Striatal Dopamine Signaling Machinery

纹状体多巴胺信号传导机制的结构和功能

• 批准号: 10589076
• 负责人: Pascal Simon Kaeser
• 金额: $ 54.97万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2027-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10589076
• 关键词: Ablation; Acetylcholine; Action Potentials; Affinity; Architecture; Axon; Brain; Brain Diseases; Cells; Cellular biology; Cholinergic Receptors; Code; Communication; Corpus striatum structure; Data; Defect; Diffuse; Diffusion; Dopamine; Dopamine D1 Receptor; Dopamine D2 Receptor; Dopamine Receptor; Electrophysiology (science); Endocytosis; Exocytosis; Extracellular Space; Funding; G-Protein-Coupled Receptors; Glutamates; Goals; Image; Interneurons; Laboratories; Lead; Mediating; Membrane; Midbrain structure; Modeling; Molecular; Movement; Mus; Nerve; Nerve Degeneration; Neuromodulator; Neurons; Parkinson Disease; Pathology; Pathway interactions; Phase; Positioning Attribute; Property; Proteins; Receptor Activation; Recycling; Regulation; Role; Signal Transduction; Site; Slice; Speed; Structure; Synapses; Synaptic Cleft; Synaptic Transmission; System; Testing; Three-Dimensional Image; Vesicle; Work; biomarker identification; cholinergic; cholinergic neuron; dopaminergic neuron; experimental study; functional plasticity; insight; knockout gene; meter; millisecond; molecular assembly/self assembly; molecular marker; nanometer; nanoscale; nervous system disorder; neuronal cell body; neuroregulation; neurotransmitter release; presynaptic; receptor; superresolution microscopy; tool; trafficking; transmission process; ultra high resolution; voltage

Summary Dopamine is an important neuromodulator and pathologies in dopamine signaling are a hallmark of brain disease. Despite these roles, the organization and regulation of dopamine signaling are incompletely understood. The long-term goal of this project is to dissect the cell biology of axonal dopamine transmission. Spatial and temporal features of dopamine signaling are different from synaptic transmission. At conventional synapses, nanometer-scale synaptic structure enables robust receptor activation at sub-millisecond speeds and restricts communication to point-to-point contacts between select neurons. In contrast, dopamine is a volume transmitter that diffuses through the extracellular space after exocytosis and may influence many cells through G-protein coupled receptors. These properties suggest that dopamine transmission is slow and diffuse. Recent data from several laboratories, including some generated during the previous funding cycle, however, have revealed that dopamine transmission is highly dynamic and, in some cases, remarkably precise. Furthermore, dopamine release is powerfully and rapidly regulated by local cholinergic interneurons in the striatum. These findings suggest that the coding of dopamine volume transmission is more precise than previously thought. A major question that arises is how the architecture for dopamine transmission can support precise signaling. Our overarching model is that molecular machinery has evolved to support broad dopamine coding scales. We build on our previous findings that axonal dopamine exocytosis is executed with millisecond precision by sparse, sophisticated protein machinery typically present at synapses. In aim 1, we zoom in on the powerful local regulation and ask how cholinergic neurons trigger dopamine release. Based on preliminary data, we hypothesize that activity in cholinergic interneurons induces ectopic action potential firing in dopamine axons to trigger dopamine secretion. Our goal is to test this hypothesis and to understand the underlying mechanisms. Identification of an endogenous mechanism for ectopic axonal action potential initiation away from the dopamine neuron soma has important implications for dopamine neuron function. In aim 2, we dissect the organization of dopamine receptors relative to release sites. We build on recent work that identified markers for these sparse secretory sites. Our preliminary data reveal that dopamine receptors are clustered one to two micrometers away from release sites and suggest differences in D1 vs. D2 receptor distributions. We will systematically assess release-receptor organization in super-resolved 3D-images of large striatal volumes and will mechanistically dissect how it is set up. We propose that the organization is different from nanoscale synaptic structure and from the diffuse organization often associated with volume transmission, and may be suited to mediate distinct pathway activation by switches in dopamine neuron firing modes. Our work will dissect the organization of specialized dopamine signaling architecture and rapid, local triggering mechanisms of dopamine release in the vertebrate striatum.

概括 多巴胺是重要的神经调节剂，多巴胺信号传导中的病理是大脑的标志 疾病。尽管有这些作用，但多巴胺信号传导的组织和调节尚未完全理解。 该项目的长期目标是剖析轴突多巴胺传播的细胞生物学。 多巴胺信号的空间和时间特征与突触传播不同。在常规 突触，纳米尺度的突触结构可在亚毫秒速度下激活强大的受体激活 将沟通限制在某些神经元之间的点对点接触。相反，多巴胺是一卷 胞吐作用后通过细胞外空间扩散的发射器，可能会通过 G蛋白偶联受体。这些特性表明多巴胺的传播缓慢而弥漫。最近的 但是 表明多巴胺传播是高度动态的，在某些情况下非常精确。此外， 多巴胺释放受纹状体中局部胆碱能中间神经元的强大和迅速调节。这些 研究结果表明，多巴胺体积传输的编码比以前想象的要精确。 出现的一个主要问题是多巴胺传输的体系结构如何支持精确 信号。我们的总体模型是分子机械已经发展为支持广泛的多巴胺编码 秤。我们以前的发现为基础，即轴突多巴胺胞吐作用以毫秒精度执行 通过稀疏，复杂的蛋白质机械通常存在于突触处。在AIM 1中，我们放大了强大的 局部调节并询问胆碱能神经元如何触发多巴胺释放。根据初步数据，我们 假设该活性在胆碱能中间神经元中诱导多巴胺轴突中的异位作用电势发射到 触发多巴胺分泌。我们的目标是检验这一假设并了解基本机制。 鉴定异位轴突作用势启动的内源性机制远离多巴胺 神经元SOMA对多巴胺神经元功能具有重要意义。在AIM 2中，我们剖析了组织 多巴胺受体相对于释放位点的。我们基于确定这些标记的最新工作 稀疏的分泌站点。我们的初步数据表明，多巴胺受体聚集了一到两个微米 远离释放位点，并暗示D1与D2受体分布的差异。我们将系统地 评估大型纹状体体积的超级分辨3D图像中的释放受体组织，并将 机械地剖析其设置方式。我们建议该组织与纳米级突触不同 结构和弥漫性组织通常与音量传输相关，并且可能适合 通过多巴胺神经元发射模式中的开关介导不同的途径激活。 我们的工作将剖析专业多巴胺信号架构的组织和快速的本地 在脊椎动物纹状体中触发多巴胺释放的机制。