Alcohol Regulation of Synaptic and Extrasynaptic GluN2B-NMDA Receptors in BNST

描述（由申请人提供）：酒精中毒是一种进行性复发障碍，尽管目前治疗，复发率仍为50-90%。新的治疗策略的发展需要对酒精中毒的神经生物学基础的理解。复发的主要原因是与酒精戒断相关的负面影响（即焦虑和抑郁）。终纹床核是一个与酒精戒断相关的负面影响有关的大脑区域。BNST的长期适应是通过神经递质谷氨酸和NMDA受体（NMDAR）发生的。在BNST中，我最近的工作表明，酒精的急性和慢性作用是由特定的NMDAR亚基（GluN2B）引起的。此外，慢性酒精导致通过这些GluN2B-NMDARs在突触外位置的传播增加。通过突触外GluN2B-NMDARs的信号传导与许多病理状况有关；然而，慢性酒精后GluN2B-NMDARs上调和重新定位的机制尚不清楚。在本提案中，我将使用一种新颖的、高度特异性的基于发现的蛋白质组学方法，结合电生理和生化技术，来鉴定酒精诱导的突触和突触外位置GluN2B相互作用蛋白的变化。初步研究表明，慢性酒精可能会改变突触内连接NMDARs和信号伙伴的蛋白质（Homer、GKAPs、Shank、mGlur5和PSD蛋白）。我认为，慢性酒精对这些蛋白质的不稳定作用允许GluN2B-NMDARs的重新定位（Aim 1）。mGluR5是另一种谷氨酸受体，已被证明可以调节BNST的可塑性。这些受体也是metmetplasticity （NMDARs的可塑性）和其他区域发育亚基从GluN2A向GluN2B转移的介质。因此，mGluR5信号是慢性酒精后GluN2B-NMDARs增强的强有力候选者（Aim 2）。虽然了解成年人这些关键的神经适应是关键，但临床数据表明，酒精依赖的最强预测因子是

DESCRIPTION (provided by applicant): Alcoholism is a progressive relapsing disorder, with relapse rates from 50-90% in spite of current treatments. The development of new treatment strategies requires an understanding of the neurobiological underpinnings of alcoholism. A primary source of relapse is the negative affect (i.e. anxiety and depression) associated with alcohol withdrawal. The bed nucleus of the stria terminalis, BNST, is a brain region implicated in this negative affect associated with alcohol withdrawal. Long-term adaptations in the BNST occur through the neurotransmitter glutamate and the NMDA receptor (NMDAR). In the BNST, my recent work illustrates that the acute and chronic actions of alcohol are caused by a particular NMDAR subunit (GluN2B). Further, chronic alcohol leads to an increase in transmission through these GluN2B-NMDARs at extrasynaptic locations. Signaling through extrasynaptic GluN2B-NMDARs has been connected to a number of pathological conditions; however, the mechanisms underlying the upregulation and relocation of GluN2B-NMDARs after chronic alcohol are unknown. In this proposal, I will be using a novel, highly specific discovery-based proteomic approach in conjunction with electrophysiological and biochemical techniques to identify alcohol-induced changes in GluN2B interacting proteins in synaptic and extrasynaptic locations. Preliminary work suggests that chronic alcohol may alter proteins that link NMDARs and signaling partners within the synapse (Homer, GKAPs, Shank, mGlur5, and PSD proteins). I propose that destabilization of these proteins by chronic alcohol allows for the relocalization o GluN2B-NMDARs (Aim 1). mGluR5 is another glutamate receptor that has been shown to modulate plasticity in the BNST. These receptors are also known mediators of metaplasticity (plasticity of NMDARs) and the developmental subunit shifts from GluN2A to GluN2B in other regions. Therefore, mGluR5 signaling is a strong candidate for the enhancement of GluN2B-NMDARs following chronic alcohol (Aim 2). While understanding these critical neuroadaptations in adults is key, clinical data demonstrates that the strongest predictor for alcohol dependence is adolescent alcohol use. Basic research finds many differential effects of alcohol between adolescents and adults; one of these being prolonged negative affect during withdrawal from chronic alcohol. The cortex and hippocampus (BNST inputs) undergo declines in NMDAR abundance and shifts in NMDAR subunit composition (GluN2B to 2A) during adolescence. In contrast, the BNST seems to retain high GluN2B into adulthood. This intersection of these differential developmental trajectories within the BNST is likely to culminate in unique regulation of excitatory transmission and plasticity during adolescence. Therefore, the independent (R00) phase of this proposal will investigate alcohol-driven dynamic regulation of NMDAR composition, localization, and signaling during adolescence.