Hippocampal neurotoxicity induced by ethanol withdrawal

乙醇戒断引起的海马神经毒性

• 批准号: 6897859
• 负责人: JOHN M. LITTLETON
• 金额: $ 36.83万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6897859
• 关键词: NMDA receptors; autoradiography; calcium channel blockers; calcium flux; drug withdrawal; ethanol; fluorescence microscopy; glutamate receptor; glutamates; high performance liquid chromatography; hippocampus; laboratory rat; neurotoxicology; neurotransmitter antagonist; neurotransmitter transport; polyamines; protein localization; protein structure function; radiotracer; receptor sensitivity; tissue /cell culture

DESCRIPTION (provided by applicant): A model system has been developed utilizing organotypic cultures of rat hippocampus in which a single cycle of ethanol exposure and removal results in significant "spontaneous" neuronal death, mainly in the pyramidal cells of the CA1 region. This in vitro model is potentially valuable for understanding the mechanisms underlying alcoholic brain damage, arguably the most important preventable cause of dementia in the USA. The data obtained thus far suggest that, in this model, neuronal damage is mostly excitotoxic and occurs during ethanol withdrawal. The primary hypothesis is that ethanol-induced adaptations in the glutamatergic system lead, on withdrawal of ethanol, to a cascade of changes including synaptic hyperactivity, network excitation, and excess release of endogenous glutamate and polyamines. These mediators then co-activate glutamate/NMDA receptors (NMDARs) that may be "supersensitive" to both agents, and which cause toxic Ca2+ entry. The primary specific aim is test these hypotheses and to elucidate the pre-synaptic and post-synaptic mechanisms that lead to withdrawal-induced toxicity in this model. Selective antagonists for ionotropic and metabotropic glutamate receptors and calcium channels will be used to probe mechanisms for initial synaptic excitation (calcium orange fluorescence microscopy), release of glutamate and polyamines (HPLC), distribution and sensitivity of NMDARs ([125I]MK801 autoradiography) and the relation between cumulative Ca2+ uptake (radiotracer 45Ca2+) and neurotoxicity (propidium iodide fluorescence microscopy). A second major aim is to investigate the role of network excitation in these changes by studying effects of transecting neural pathways within the culture on these parameters. Mechanisms that rely on transsynaptic activation should be prevented by this procedure. All studies in the project will focus on the regional distribution of toxicity within the slice culture, and the mechanisms that contribute to this distribution. In addition to testing the hypotheses, these experiments should suggest novel therapeutic interventions into alcohol-induced neurodegenerative disease, and elucidate why specific neuronal phenotypes are susceptible to alcohol withdrawal. Both are research priorities in the recent NIAAA Review of Neuroscience and Behavioral Science Portfolio.

描述（由申请人提供）：使用大鼠海马的器官培养物开发了模型系统，其中单个乙醇暴露和去除周期导致显着的“自发”神经元死亡，主要是在CA1区域的锥体细胞中。这种体外模型对于理解酒精性脑损伤的机制可能具有价值，这可以说是美国痴呆症最重要的原因。迄今为止获得的数据表明，在此模型中，神经元损伤主要是兴奋性毒性，并且发生在乙醇提取期间。主要的假设是乙醇诱导的谷氨酸能系统的适应性导致乙醇戒断，导致一系列变化，包括突触多动症，网络激发以及内源性谷氨酸和多胺的过量释放。然后，这些介体将谷氨酸/NMDA受体（NMDAR）共同激活，对两种药物都可能“超敏感”，并且引起有毒的Ca2+进入。主要目的是检验这些假设，并阐明突触前和突触后机制，这些机制导致该模型中戒断诱导的毒性。选择性拮抗剂的离子和代谢型谷氨酸受体和钙通道的选择性拮抗剂将用于探测初始突触激发（钙橙色荧光显微镜），谷氨酸和多胺（HPLC）（HPLC）（HPLC），NMDARS的分布和敏感性（[125i] MK801自动ca）的分布和敏感性的机制，以及cas的分布和敏感性。 （放射性练习45CA2+）和神经毒性（碘化丙啶荧光显微镜）。第二个主要目的是通过研究培养物中对这些参数的横断神经途径的影响来研究网络激发在这些变化中的作用。该程序应防止依赖于透射激活的机制。该项目中的所有研究都将侧重于切片培养中毒性的区域分布，以及有助于这种分布的机制。除了检验假设外，这些实验还应表明对酒精引起的神经退行性疾病进行新的治疗干预，并阐明为什么特定的神经元表型易于戒酒。两者都是NIAAA最近对神经科学和行为科学作品集的研究重点。