Regulation of NMDA Receptor Localization by Ethanol

乙醇对 NMDA 受体定位的调节

• 批准号: 7338037
• 负责人: Paula Hoffman
• 金额: $ 35.2万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-15 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7338037
• 关键词: AMPA Receptors; Affect; Alcohol withdrawal syndrome; Antibodies; Attention; Biochemical; Brain; C57BL/6 Mouse; Cell membrane; Cell surface; Cells; Chromosome Pairing; Chronic; Cognition; Cognitive deficits; Confocal Microscopy; Diet; Endocytosis; Ethanol; Extracellular Domain; Fluorescent Antibody Technique; Glutamate Receptor; Glutamates; Hippocampus (Brain); Immunoblotting; Immunofluorescence Immunologic; In Vitro; Investigation; Lead; Ligand Binding; Liquid substance; Localized; Measurement; Measures; Molecular; Mus; N-Methyl-D-Aspartate Receptors; N-Methylaspartate; NR1 gene; Neurons; Pattern; Phosphorylation; Phosphotransferases; Physical Dependence; Predisposition; Preparation; Process; Property; Protein Kinase; Protein Subunits; Proteins; RNA Splicing; Rate; Rattus; Regulation; Role; Seizures; Slice; Synapses; Synapsins; Synaptic Membranes; Synaptic Receptors; Synaptic plasticity; System; Techniques; Time; Tissues; Variant; Withdrawal; addiction; alcohol craving; alcohol effect; alcohol exposure; alcohol reinforcement; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; amino 3 hydroxy 5 methylisoxazole 4 propionate; base; chronic alcohol ingestion; cognitive change; crosslink; excitotoxicity; feeding; hippocampal pyramidal neuron; human NR1 protein; in vivo; kinase inhibitor; neurotoxicity; novel therapeutics; postsynaptic density protein; presynaptic; presynaptic density protein 95; receptor; receptor binding; receptor function

Chronic ethanol exposure has been shown to increase NMDA receptor ligand binding and the levels of receptor subunit proteins in mouse and rat brain. The increase in hippocampal NMDA receptors has been suggested to be related to the occurrence of ethanol withdrawal seizures and to increased susceptibility to glutamate-induced excitotoxicity, and could also result in altered cognition and could contribute to changes in ethanol reinforcement and "craving" for ethanol. In contrast to NMDA receptors, little attention has been given to ethanol-induced alterations in non-NMDA (AMPA) glutamate receptors, which could also contribute to long-term cognitive changes following ethanol exposure and withdrawal. Although the time course of changes in ligand binding to the hippocampal NMDA receptor parallels the time course for the occurrence and dissipation of ethanol withdrawal seizures, long-term adaptive changes in NMDA and/or non-NMDA glutamate receptors may involve not only increases in receptor subunit protein levels, but also altered cell surface expression and/or synaptic localization of the receptors. Changes in these properties, which have important functional consequences, could occur either in the absence or presence of increased receptor synthesis. We propose to assess adaptations in synaptic targeting of NMDA and AMPA receptors following chronic ethanol treatment that produces physical dependence and withdrawal. Such receptor changes may be long-lasting, and contribute to cognitive deficits as well as prolonged increases in susceptibility to neurotoxicity. Using both biochemical and immunohistochemical techniques, in Aim 1 we will investigate adaptations in glutamate receptor synaptic localization and cell surface expression in hippocampus of C57BL/6 mice that have ingested ethanol chronically in a liquid diet, and undergone withdrawal. Increases in NMDA receptor function and subunit protein levels have also been found in cultured mouse and rat neurons that have been exposed chronically to ethanol, and thus in Aim 2 we will investigate glutamate receptor localization in ethanol-treated/withdrawn hippocampal neurons, to determine parallels between effects of ethanol in this in vitro system and in vivo. These studies will then allow a detailed investigation in Aim 3 of the molecular mechanisms that lead to changes in NMDA and/or AMPA receptor properties as a result of chronic ethanol exposure. The proposed studies go beyond previous phenomenological observations to determine how ethanol exposure results in adaptations that affect synaptic plasticity and may contribute to the CNS changes associated with addiction. Understanding these mechanisms can provide novel therapeutic approaches to ameliorating the neuronal consequences of chronic ethanol ingestion and withdrawal.

慢性乙醇暴露已被证明可增加小鼠和大鼠脑内NMDA受体配体结合和受体亚基蛋白水平。海马NMDA受体的增加被认为与乙醇戒断性癫痫的发生和谷氨酸诱导的兴奋性毒性的易感性增加有关，也可能导致认知改变，并可能导致乙醇强化和对乙醇的“渴望”的变化。与NMDA受体相反，很少有人关注乙醇诱导的非NMDA （AMPA）谷氨酸受体的改变，这也可能导致乙醇暴露和戒断后的长期认知变化。尽管与海马NMDA受体结合的配体变化的时间过程与乙醇戒断性癫痫发作的发生和消散的时间过程相似，但NMDA和/或非NMDA谷氨酸受体的长期适应性变化可能不仅涉及受体亚基蛋白水平的增加，还涉及受体的细胞表面表达和/或突触定位的改变。这些具有重要功能后果的性质的变化可能发生在缺乏或存在增加的受体合成的情况下。我们建议评估NMDA和AMPA受体在慢性乙醇治疗后产生身体依赖和戒断后突触靶向的适应性。这种受体的改变可能是持久的，并导致认知缺陷以及对神经毒性的易感性的长期增加。在Aim 1中，我们将使用生化和免疫组织化学技术，研究长期摄入液体饮食中的乙醇并进行停药的C57BL/6小鼠海马中谷氨酸受体突触定位和细胞表面表达的适应性。在长期暴露于乙醇的培养小鼠和大鼠神经元中也发现了NMDA受体功能和亚基蛋白水平的增加，因此在Aim 2中，我们将研究乙醇处理/退出海马神经元中谷氨酸受体的定位，以确定乙醇在体外系统和体内系统中的作用之间的相似性。这些研究将允许在Aim 3中详细调查导致慢性乙醇暴露导致NMDA和/或AMPA受体特性变化的分子机制。拟议的研究超越了先前的现象学观察，以确定乙醇暴露如何导致影响突触可塑性的适应性，并可能导致与成瘾相关的中枢神经系统变化。了解这些机制可以为改善慢性乙醇摄入和戒断对神经元的影响提供新的治疗方法。