Integration and Dynamics of Neuromodulator Action in the Striatum

项目摘要/摘要 神经调节剂，如多巴胺和阿片类药物，动态调节突触强度和内在 神经元的特性，从而调节神经回路的输出和改变行为。他们的改变 与帕金森氏症和成瘾等毁灭性疾病有关。纹状体是一种理想的 研究神经调节，因为它接收到大量与行为相关的神经调节物质。此外 除了对神经元的电兴奋性的影响外，神经调节剂还会产生生化变化， 被认为是适应行为的关键。在纹状体的一个投射神经元内，不同的 神经调节剂已被提出竞争性和双向调节突触传递和 通过调节蛋白激酶A(PKA)的活性来实现可塑性。在直接和间接纹状体通路之间， 相同的神经调节剂可导致相反的变化方向(如多巴胺)或相同的变化方向(如阿片类药物 在投射神经元中的PKA活性，从而协调两条与 会产生相反的行为结果。因为神经调节剂的输入在动物体内是不断变化的 行为，PKA如何对这些动态和多样化的输入做出反应，对于理解神经调节剂是至关重要的 行动。然而，人们对这种动态反应的性质知之甚少。面临的主要挑战之一 对这个问题的理解是，缺乏对PKA活动的动态读数，以回应正在进行的 神经调节输入。鉴于PKA作为神经调节剂作用和调节器的主要整合者的作用 关于电路的可塑性，我最近开发了一种PKA活性生物传感器，它可以在基因上靶向 活体脑片中双光子荧光寿命成像显微镜(2pFLIM)所定义的神经元。至 了解纹状体中的神经调节作用，我建议在遗传鉴定中成像PKA活性 具有很高时空精度的神经元。首先，考虑到多巴胺在正常纹状体中的重要性 功能(例如调节运动和基于奖励的学习)和病理情况(例如帕金森氏症 疾病和成瘾)，我将描述直接和间接途径纹状体中PKA活性的动态变化 神经元对多巴胺释放的反应。其次，我将确定多巴胺如何与其他 调节剂，如乙酰胆碱和阿片类药物，以改变PKA活性。总之，这项研究将揭示 细胞内生化变化对持续的神经调节输入的动态响应，以及如何 神经调节器协调电路动力学。了解以下方面的集成和动态 正常情况下的神经调质作用将有助于阐明异常的神经调质信号是如何 在神经退行性疾病和成瘾等病理条件下改变纹状体功能。

PROJECT SUMMARY/ABSTRACT Neuromodulators, such as dopamine and opioids, dynamically regulate synaptic strength and intrinsic properties of neurons, thereby modulating outputs of neural circuits and modifying behavior. Their alteration is linked to devastating diseases such as Parkinson's Disease and addiction. The striatum is an ideal system to study neuromodulation since it receives a large number of behaviorally-relevant neuromodulators. In addition to their effects on the electrical excitability of neurons, neuromodulators also exert biochemical changes that are thought to be crucial for adaptive behaviors. In the striatum, within one projection neuron, different neuromodulators have been proposed to competitively and bidirectionally regulate synaptic transmission and plasticity via modulation of protein kinase A (PKA) activity. Between direct and indirect striatal pathways, the same neuromodulator can lead to either opposite (e.g. dopamine) or the same (e.g. opioid) direction of change of PKA activity in the projection neurons, thereby coordinating the two pathways that are implicated to produce opposite behavioral outcomes. Since neuromodulator inputs are constantly changing during animal behavior, how PKA responds to these dynamic and diverse inputs are crucial to understanding neuromodulator action. Nevertheless, the nature of this dynamic response is poorly understood. One of the major challenges to understanding this question is the lack of a dynamic readout of PKA activity in response to ongoing neuromodulatory inputs. Given the role of PKA as a major integrator of neuromodulator action and regulator of circuit plasticity, I have recently developed a PKA activity biosensor that can be targeted to genetically defined neurons for 2-photon Fluorescence Lifetime Imaging Microscopy (2pFLIM) in live brain slices. To understand neuromodulator action in the striatum, I propose to image PKA activity in genetically identified neurons with high spatiotemporal precision. First, given the importance of dopamine in normal striatal function (e.g. modulating movement and reward-based learning) and pathological conditions (e.g. Parkinson's Disease and addiction), I will characterize the dynamics of PKA activity in direct and indirect pathway striatal neurons in response to dopamine release. Secondly, I will determine how dopamine interacts with other modulators such as acetylcholine and opioids to alter PKA activity. In summary, this study will reveal how intracellular biochemical changes dynamically respond to ongoing neuromodulatory inputs, and how neuromodulators coordinate circuit dynamics. Understanding the integration and dynamics of neuromodulator action in normal conditions will shed light onto how abnormal neuromodulator signaling alters striatal function in pathological conditions such as neurodegenerative diseases and addiction.