Ethanol, Dependence and Mesolimbic Plasticity

乙醇、依赖性和中脑边缘可塑性

• 批准号: 7066107
• 负责人: RICHARD A MORRISETT
• 金额: $ 29.3万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-15 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7066107
• 关键词: DARPP; NMDA receptors; alcoholism /alcohol abuse; behavioral /social science research tag; biological signal transduction; confocal scanning microscopy; dopamine receptor; drug addiction; electrophysiology; ethanol; genetically modified animals; laboratory rat; long term potentiation; neural transmission; neurons; nucleus accumbens; phosphorylation; protein localization; protein protein interaction; tissue /cell culture; voltage /patch clamp; western blottings; DARPP; NMDA receptors; alcoholism /alcohol abuse; behavioral /social science research tag; biological signal transduction; confocal scanning microscopy; dopamine receptor; drug addiction; electrophysiology; ethanol; genetically modified animals; laboratory rat; long term potentiation; neural transmission; neurons; nucleus accumbens; phosphorylation; protein localization; protein protein interaction; tissue /cell culture; voltage /patch clamp; western blottings

DESCRIPTION (provided by applicant): Extensive evidence suggests that interactions between mesolimbic dopaminergic and glutamatergic systems are critically involved in the processes underlying ethanol dependence. Activation of dopamine D-1 receptors as well as NMDA receptors is required for various models of ethanol self-administration, dependence and sensitization. Evidence from our lab and others indicates that NMDA receptor-function and LTP are both markedly enhanced in NAc slices from rats chronically exposed to ethanol. We have recently identified a novel mechanism regulating the ethanol sensitivity of NMDA receptors mediated via D1 activation of an important intracellular component of dopaminergic signaling, DARPP-32. Knockout animals lacking DARPP-32 or D-1 receptors display strikingly similar defects in ethanol self-administration suggesting that this component of dopaminergic signaling may indeed be critical for the development of ethanol dependence. Here, we propose that D1/DARPP-32 dependent regulation of the ethanol sensitivity of NMDA receptors on medium spiny neurons (MSNs) of the NAc promotes NMDA receptor-function to support svnaptic plasticity and contribute to activation of mesolimbic structures in the development of ethanol dependence. This proposal focuses upon the interactions between D1, DARPP-32 and NMDA-dependent processes in ethanol neuroadaptation and uses two chronic ethanol model systems to identify these interactions: (1) an organotypic or brain slice explant culture system containing the major components of the mesocorticolimbic system, and (2) acute slices containing NAc prepared from rats treated with ethanol via inhalation. Four aims are proposed to assess D1 modulation of ethanol sensitivity in NAc neurons following chronic ethanol treatment to model ethanol neuroadaptation. Aim 1 is designed to directly measure ethanol sensitivity of NMDA receptors electrophysiologically though detection of NMDA mEPSCs evoked in the presence of Sr++. Aim 2 measures changes in plasticity by assessing NMDA receptor-dependent LTP. Aims 3 and 4 use immunoblot and confocal microscopy to determine the changes in phosphorylation of DARPP- 32 and NR1 (aim 4) and their subcellular co-localization (aim 5). Taken together, these aims should provide important new information into the synaptic and molecular alterations that underlie plasticity in mesolimbic structures that may contribute to alcohol addiction.

描述（由申请人提供）：广泛的证据表明，中唇多巴胺能和谷氨酸能系统之间的相互作用与乙醇依赖性的过程中非常重要。多巴胺D-1受体的激活以及NMDA受体的激活是乙醇自我给药，依赖性和敏化的各种模型所必需的。我们实验室和其他实验室的证据表明，NMDA受体功能和LTP在长期暴露于乙醇的大鼠的NAC切片中都明显增强。我们最近确定了一种新的机制，该机制通过D1激活多巴胺能信号传导的D1激活介导的NMDA受体的乙醇敏感性，DARPP-32。缺乏DARPP-32或D-1受体的敲除动物在乙醇自我给药中表现出明显相似的缺陷，这表明多巴胺能信号的这种成分确实对于乙醇依赖性的发展确实至关重要。在这里，我们建议NAC中NMDA受体的乙醇敏感性的D1/DARPP-32调节NAC的乙醇敏感性促进NMDA受体功能，以支持乙醇依赖性乙醇依赖性发育中的中脂质结构的激活。该提议着重于乙醇神经适应中D1，DARPP-32和NMDA依赖性过程之间的相互作用，并使用两个慢性乙醇模型系统来识别这些相互作用：（1）通过含有中皮质胶质系统的主要组成部分和（2）Actection anc anc anc anc anc anc anc anc anc anc anc anc anc anc contection的相互作用。提出了四个目的，以评估慢性乙醇处理后NAC神经元中乙醇敏感性的D1调节，以模拟乙醇神经适应。 AIM 1旨在直接测量NMDA受体在电生理学上的乙醇敏感性，尽管在存在SR ++的情况下引起的NMDA MEPSC的检测。 AIM 2通过评估NMDA受体依赖性LTP来衡量可塑性的变化。目标3和4使用免疫印迹和共聚焦显微镜确定Darpp-32和NR1（AIM 4）及其亚细胞共定位（AIM 5）的磷酸化变化。综上所述，这些目标应为突触和分子改变提供重要的新信息，这些新信息是中唇质结构中可塑性的基础，这可能导致酒精成瘾。