Electrochemical Analysis of Dopamine Release

多巴胺释放的电化学分析

• 批准号: 8132779
• 负责人: Margaret E Rice
• 金额: $ 7.25万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-05-01 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8132779
• 关键词: Address; Brain Diseases; Cardiac Myocytes; Cavia; Cell physiology; Cells; Characteristics; Cognitive; Corpus striatum structure; Data; Dependence; Detection; Diabetes Mellitus; Disease; Dopamine; Dorsal; Endogenous Factors; Exposure to; Figs - dietary; Functional disorder; Funding; Generations; Glutamates; Goals; Head; Heart Diseases; Hour; Hydrogen Peroxide; Immunofluorescence Immunologic; Individual; Interneurons; Ions; Lead; Learning; Left; Link; Lipid Peroxidation; Literature; Mediating; Membrane Potentials; Methods; Midbrain structure; Mission; Motor; Mus; N-Methyl-D-Aspartate Receptors; National Institute of Neurological Disorders and Stroke; Neurons; Oxidative Stress; Pancreas; Parkinson Disease; Pathway interactions; Peroxides; Physiological; Progress Reports; Reactive Oxygen Species; Regulation; Research; Research Design; Rewards; Rice; Role; Schizophrenia; Signal Transduction; Slice; Substantia nigra structure; System; Testing; Therapeutic Intervention; Time; Tissues; Ventral Tegmental Area; Work; addiction; base; brain cell; brain pathway; cholinergic; dopaminergic neuron; fluorescence imaging; gamma-Aminobutyric Acid; improved; insight; mitochondrial membrane; novel; pars compacta; research study; transmission process

DESCRIPTION (provided by applicant): Dopamine (DA) is a key transmitter in motor, cognitive, and reward pathways of the brain, with dysfunction of DA transmission linked to significant disorders, including Parkinson's disease, schizophrenia, and addiction. The long-term goal of this project is to identify local factors that regulate somatodendritic DA release from DA neurons in the substantia nigra pars compacta (SNc) and ventral tegmental area (VTA) and axonal DA release in striatum. In the previous funding period, we focused on DA release regulation by endogenous glutamate, GABA, and Ca2+ entry, using real-time voltammetric recording of evoked DA release. We discovered that hydrogen peroxide (H2O2), a reactive oxygen species (ROS), is an intracellular messenger in SNc DA neurons that both modulates cell firing rate and inhibits somatodendritic DA release. By contrast, in dorsal striatum, H2O2 is a diffusible messenger that mediates regulation of axonal DA release by glutamate and GABA. These effects of H2O2 are mediated by the activation of ATP-sensitive K+ (KATP) channels. Proposed work will provide mechanistic insight into regulation of DA transmission by H2O2, as well as indicate functional consequences of H2O2 signaling on somatodendritic and axonal DA release. Aim 1 will test the hypothesis that H2O2 activates KATP channels by decreasing channel sensitivity to ATP; Aim 2 will determine the ionic dependence of H2O2 generation; Aim 3 will investigate the role of H2O2 generation in the regulation of somatodendritic DA release and DA cell physiology by glutamatergic NMDA receptors; and Aim 4 will evaluate the temporal and spatial characteristics of glutamate-dependent H2O2 signaling in dorsal striatum. Methods include voltammetric detection of DA release, whole-cell and excised patch recording, and fluorescence imaging of H2O2, intracellular ions, and mitochondrial membrane potential. Experimental systems include isolated DA neurons, transfected cells, and brain slices from guinea pigs and from mice lacking a specific KATP channel subtype. Several brain disorders that involve DA dysfunction, including Parkinson's disease and schizophrenia, have also been linked to oxidative stress. Proposed studies will clarify how endogenous H2O2 normally regulates DA release. Because unregulated H2O2 can lead to oxidative stress, however, the findings may also point to possible targets for therapeutic intervention in these debilitating disorders. This project is based on our novel finding that hydrogen peroxide is an endogenous factor that regulates the nigrostriatal dopamine pathway. Understanding factors that regulate this pathway is important, since it is nigrostriatal dopamine that is lost in Parkinson's disease, leaving individuals unable to move. Proposed studies will clarify how endogenous hydrogen peroxide normally regulates dopamine release and dopamine neuron activity in this pathway. Additionally, because unregulated peroxide can lead to oxidative stress, which is a causal factor in Parkinson's disease, the findings may also point to possible new targets for therapeutic intervention, consistent with one aspect of the mission of NINDS.

描述（由申请人提供）：多巴胺（DA）是大脑运动、认知和奖赏通路中的关键递质，DA传递功能障碍与重大疾病有关，包括帕金森病、精神分裂症和成瘾。本项目的长期目标是确定调节黑质腹侧被盖区（VTA）和黑质旁核（SNc）DA神经元体树突DA释放以及纹状体轴突DA释放的局部因素。在前一个资助期，我们专注于DA释放调节内源性谷氨酸，GABA和Ca2+的进入，使用实时伏安记录诱发DA释放。我们发现，过氧化氢（H2O2），活性氧（ROS），是在SNc DA神经元的细胞内信使，既调节细胞放电率和抑制体树突DA释放。相反，在背侧纹状体，H2O2是一个可扩散的信使，介导调节轴突DA释放的谷氨酸和GABA。H2O2的这些作用是通过激活ATP敏感性K+（KATP）通道介导的。建议的工作将提供机制的洞察调节DA传输H2O2，以及指示功能的后果H2O2信号对体树突和轴突DA释放。目的1验证H_2O_2通过降低KATP通道对ATP的敏感性而激活KATP通道的假说，目的2确定H_2O_2产生的离子依赖性，目的3研究H_2O_2产生在多巴胺能NMDA受体调节体树突DA释放和DA细胞生理中的作用，目的4研究H_2O_2产生对DA释放的影响。目的4研究背侧纹状体谷氨酸依赖性H2O2信号的时空特征。方法包括伏安检测DA释放，全细胞和切除的补丁记录，和过氧化氢，细胞内离子和线粒体膜电位的荧光成像。实验系统包括分离的DA神经元，转染的细胞，以及来自豚鼠和缺乏特定KATP通道亚型的小鼠的脑切片。 一些涉及DA功能障碍的大脑疾病，包括帕金森病和精神分裂症，也与氧化应激有关。拟议的研究将阐明内源性H2O2通常如何调节DA的释放。然而，由于不受调节的H2O2可导致氧化应激，因此这些发现也可能指向这些衰弱性疾病的治疗干预的可能靶点。 这个项目是基于我们的新发现，过氧化氢是一种内源性因子，调节黑质纹状体多巴胺通路。了解调节这一途径的因素是很重要的，因为它是黑质纹状体多巴胺，在帕金森病中丢失，使个人无法移动。拟议的研究将阐明内源性过氧化氢如何正常调节多巴胺的释放和多巴胺神经元活动在这一途径。此外，由于不受调节的过氧化物可导致氧化应激，这是帕金森病的一个致病因素，这些发现也可能指向治疗干预的可能新靶点，与NINDS的使命的一个方面一致。