Alcohol Actions on NMDA Receptor Gating Domains

描述（由申请人提供）：本研究的长期目标是了解酒精调节 NMDA 受体功能的分子位点和机制。尽管 NMDA 受体是酒精作用的主要中枢神经系统靶标，但酒精对 NMDA 受体作用的分子位点和机制仍不完全清楚。酒精通过影响离子通道门控来抑制 NMDA 受体 (1;2)，该实验室和其他实验室的最新研究结果指出了酒精作用中膜相关 (M) 结构域的位点。该实验室的工作已确定并表征了 NMDA 受体 NR2A 亚基的第三和第四膜相关 (M) 结构域中的氨基酸位置，这些位置影响离子通道的门控和酒精敏感性；这些位置中至少有两个是酒精作用的推定位点。尽管 NR2A 亚基在哺乳动物大脑中占主导地位，但最近的证据支持 NR2B 亚基在 CNS 功能 (3-6) 和酒精作用 (7-11) 中的重要性。在这些研究中，我们将使用全细胞、单通道和大膜片浓度跳跃膜片钳记录，结合突变体循环分析和动力学模型，以及分子模型和分子动力学模拟，来测试中心假设，即酒精与 M3 和 M4 结构域中的特定位点相互作用，通过离子通道门控的变化来调节 NMDA 受体活性，并且这些位点以及具体的抑制机制在 NR2 亚基和不同醇之间存在差异。这些研究将提供迄今为止关于酒精对 NMDA 受体作用机制的最完整信息；具体来说，他们将为乙醇和其他醇与其作用位点对 NMDA 受体的相互作用以及乙醇对 NMDA 受体动力学的影响提供重要见解。通过识别 NMDA 受体门控区域中调节酒精抑制敏感性的位点，以及可能直接结合酒精的位点，这些研究还将确定治疗酒精使用障碍的新治疗靶点。因此，从这些研究中获得的知识可以为更好地理解 NMDA 受体在酒精的神经生理和行为影响中的精确作用以及更好地治疗酒精滥用和酒精中毒提供基础。

DESCRIPTION (provided by applicant): The long term goal of this study is to understand the molecular sites and mechanisms through which alcohol acts to modulate the function of NMDA receptors. Although NMDA receptors are major CNS targets of alcohol action, the molecular sites and mechanisms of action of alcohol on NMDA receptors are still incompletely understood. Alcohol inhibits NMDA receptors by influencing ion channel gating (1;2), and results of recent studies from this and other laboratories point to sites in the membrane-associated (M) domains in the actions of alcohol. Work from this laboratory has identified and characterized amino acid positions in the third and fourth membrane-associated (M) domains of the NMDA receptor NR2A subunit that influence both gating and alcohol sensitivity of the ion channel; at least two of these positions are putative sites of alcohol action. Although the NR2A subunit predominates in the mammalian brain, recent evidence supports the importance of the NR2B subunit in CNS function (3-6) and alcohol action (7-11). In these studies we will use whole-cell, single-channel, and macropatch concentration-jump patch-clamp recording coupled with mutant cycle analysis and kinetic modeling, as well as molecular modeling and molecular dynamics simulations, to test the central hypothesis that alcohol interacts with specific sites in the M3 and M4 domains to modulate NMDA receptor activity via changes in ion channel gating, and that these sites, and the specific mechanism of inhibition, differ among NR2 subunits and different alcohols. These studies will provide the most complete information to date on the mechanism of alcohol action on the NMDA receptor; specifically, they will provide critical insights into both interaction of ethanol and other alcohols with their sites of action on the NMDA receptor, and the influence of ethanol on NMDA receptor kinetics. By identifying sites in the NMDA receptor gating regions that modulate sensitivity to inhibition by alcohol, as well as sites that are likely to directly bind alcohol, these studies will also identify novel therapeutic targets for the treatment of alcohol use disorders. The knowledge gained from these studies could thus provide a basis for a better understanding of the precise role of the NMDA receptor in the neurophysiological and behavioral effects of alcohol, as well as better pharmacotherapy of alcohol abuse and alcoholism.