Synaptic Transmission, Plasticity and Integration in the Subthalamic Nucleus

描述（由申请人提供）：帕金森病（PD）中运动不能、运动迟缓和僵硬的衰弱性运动症状与连接的GABA能外苍白球（GPe）和丘脑底核（GBE）以及相关的皮质-基底节-丘脑皮质网络中神经元活动的频率和模式变化密切相关。在特发性和实验性PD中，GPe和GPe分别表现出活动减退和活动过度，以及异常的同步、节律性和爆发性放电。在PD实验模型中，黑质多巴胺神经元急性丧失后，异常的多巴胺活性缓慢出现并逐渐增强，直到2-3周后达到稳定的最大值。这个过程表明细胞和网络特性的适应性变化有助于帕金森病患者STN活动的发展。由于GPe有效地调节频率和同步的突触活动，并可以产生反弹爆发放电的突触，GPe-突触传递进行了比较，在控制和6-羟基多巴胺损伤的啮齿动物，使用电生理学，分子和解剖学方法。这些研究表明，在多巴胺丧失后2-3周，GPe-TdR投射通过突触连接的增殖而大大加强。因此，这种改变可能是PD中出现异常GPe-CRP活性的主要原因。在这里，我们建议研究的时间进程，性质，潜在的机制和功能的后果，改变GPe-多巴胺的损失后，传输。我们建议应用细胞生理学来测量GPe-β突触功能和功能障碍;解剖学方法来定义GPe-β突触可塑性的结构和分子基础;双光子激光扫描显微镜和光遗传学来定义触发突触可塑性的Ca 2+来源;病毒载体，分子和生物化学方法来定义潜在的分子机制，使我们能够操纵GPe-β传递。我们提出了四个具体目标：目标1。确定实验性PD中GPe-β突触传递改变的时程和性质。我们假设GPe-β传递的改变与帕金森病患者活动的发展相关;目的2。确定导致实验性PD中GPe-beta突触传递增强的触发因素。我们假设，超活化的谷氨酸受体和/或Cav通道导致GPe-Glu突触传递在实验PD增强;目的3。确定GPe-突触传递增强的细胞和分子机制。我们假设，超活化的谷氨酸受体和/或过度活跃的谷氨酸神经元导致细胞内Ca 2+的增加，激活信号级联介导突触增强和增殖;目的4。确定慢性多巴胺耗竭对多巴胺神经元动作电位依赖性抑制的影响。我们假设，自主活动的GPe-ESTA神经元不改变多巴胺耗竭和GPe-ESTA抑制增加，通过增强GPe-ESTA连接。

DESCRIPTION (provided by applicant): The debilitating motor symptoms of akinesia, bradykinesia and rigidity in Parkinson's disease (PD) are intimately related to changes in the frequency and pattern of neuronal activity in the reciprocally connected GABAergic external globus pallidus (GPe) and glutamatergic subthalamic nucleus (STN) and associated cortico-basal ganglia-thalamocortical networks. In idiopathic and experimental PD the GPe and STN exhibit hypo- and hyperactivity, respectively, and abnormal synchronous, rhythmic, burst firing. Following acute loss of substantia nigra dopamine neurons in experimental models of PD abnormal STN activity emerges slowly and intensifies gradually until it reaches a stable maximum after 2-3 weeks. This process suggests that adaptive changes in cellular and network properties contribute to the development of parkinsonian STN activity. Because the GPe potently regulates the frequency and synchronization of STN activity and can generate rebound burst firing in the STN, GPe-STN transmission was compared in control and 6-hydroxydopamine-lesioned rodents using electrophysiological, molecular and anatomical approaches. These studies revealed that 2-3 weeks after loss of dopamine the GPe-STN projection had strengthened considerably through proliferation of synaptic connections. This alteration could therefore be a major contributor to the emergence of abnormal GPe-STN activity in PD. Here we propose to study the timecourse, nature, underlying mechanisms and functional consequences of alterations in GPe-STN transmission that follow the loss of dopamine. We propose to apply cellular physiology to measure GPe-STN synaptic function and dysfunction; anatomical approaches to define the structural and molecular bases of GPe-STN synaptic plasticity; 2-photon laser scanning microscopy and optogenetics to define the sources of Ca2+ that trigger synaptic plasticity; viral vector, molecular and biochemical approaches to define the underlying molecular mechanisms and enable us to manipulate GPe-STN transmission. We propose 4 Specific Aims: Aim 1. Determine the timecourse and nature of alterations in GPe-STN synaptic transmission in experimental PD. We hypothesize that alterations in GPe-STN transmission are correlated with the development of parkinsonian STN activity; Aim 2. Determine the triggers leading to potentiation of GPe-STN synaptic transmission in experimental PD. We hypothesize that hyperactivation of STN glutamate receptors and/or Cav channels leads to the potentiation of GPe-STN synaptic transmission in experimental PD; Aim 3. Determine the cellular and molecular mechanisms underlying the potentiation of GPe-STN synaptic transmission. We hypothesize that hyperactivation of STN glutamate receptors and/or hyperactivity of STN neurons leads to an increase in intracellular Ca2+, which activates signaling cascades that mediate synaptic potentiation and proliferation; Aim 4. Determine the impact of chronic dopamine depletion on action potential-dependent inhibition of STN neurons. We hypothesize that the autonomous activity of GPe-STN neurons is not altered by dopamine depletion and that GPe-STN inhibition is increased through potentiation of GPe-STN connectivity.