NOVEL MOLECULAR SITE FOR ANTIDOPAMINERGIC ACTION

描述(改编自申请人的摘要)：这是本报告的第一个目的 竞争的应用将是继续阐明分子基础 DA(尤其是类D_1)受体识别配体的能力 这种相互作用的功能后果。我们将继续利用 基于配体的分子建模的几种策略(包括传统的 和新的比较分子场分析[CoMFA]技术)来提炼 现有模型，并检验可供选择的绑定模型的假设 这些受体。这将得到基于结构的受体的补充 模特和药物设计。定点受体突变，结合 可探测突变的新型刚性配体的合成与应用 受体的空间，被假设为提供确定的结构 关于受体拓扑学的几个关键方面的信息。这又反过来 然后可以用来测试和改进D1样受体的模型。在一个 迭代的方式，我们将继续开发新的配体与新颖 受体结合或激活的机制及其对D1的选择性 而不是D5受体。这些配体将成为持续发展的有力工具 受体结构和功能的研究。第二个主要方向是 这项工作是为了了解药物-受体相互作用的后果。 尽管我们过去的工作已经提供了第一批完整的D1激动剂和 了解影响药物分子特性的因素 内在疗效，尚不清楚是什么分子机制产生了完全 而不是部分激动主义。我们将确定激活的作用 G蛋白和转导系统的各种异构体来确定 部分激动症是定量的或分级的激活：(1) G蛋白的个体群体；2)各种转导系统 (尤其是腺苷环化酶)。最后，我们将研究分子 参与脱敏和下调的机制。尽管 对其他G蛋白系统中这些现象的广泛理解，我们的 研究表明，具有明显相似特征的药物(例如，高 亲和力全D1激动剂)可以随着时间的推移引起显著不同的变化， 在体外细胞系统和完整的大脑中。使用站点定向 诱变，一系列的体外和体内系统，和强大的 药理探针室，我们将设法确定 受体结构的各个方面对调节事件都很重要。在……里面 此外，我们将确定一个或多个种群的共同激活如何 DA D2样受体影响体内的长期适应性变化。这些 研究不仅对启发式的原因有用，而且可能会影响 在几种临床情况下等待使用D1激动剂。

DESCRIPTION (adapted from applicant's abstract): This first aim of this competing application will be to continue to elucidate the molecular basis of ligand recognition by DA (especially the D1-like) receptors, and the functional consequences of such interactions. We shall continue to utilize several strategies of ligand-based molecular modeling (including traditional and novel Comparative Molecular Field Analysis [CoMFA] techniques) to refine existing models, and test the hypothesis of alternate binding models for these receptors. This will be complemented by structure-based receptor modeling and drug design. Site-directed receptor mutagenesis, coupled with the synthesis and use of novel rigid ligands that can probe the mutated space of the receptor, are hypothesized to provide definitive structural information about several key aspects of receptor topography. This in turn can then be used to test and refine models of the D1-like receptors. In an iterative fashion, we shall continue to develop new ligands with novel mechanisms of receptor binding or activation, and with selectivity for D1 versus D5 receptors. These ligands will be powerful tools for continued research on receptor structure and function. The second major direction of this work is to understand the consequence of drug-receptor interaction. Although our past work has provided the first full D1 agonists and an understanding of the molecular characteristics of drugs that affect their intrinsic efficacy, it is unclear what molecular mechanisms engender full versus partial agonism. We shall determine the role of activation of various isoforms of G-proteins and transduction systems to determine if partial agonism is quantal or graded in terms of activation of: (1) individual populations of G-proteins; and 2) various transduction systems (especially adenylate cyclases). Finally, we shall study the molecular mechanisms involved in desensitization and down-regulation. Despite extensive understanding of these phenomena in other G-protein systems, our work has shown that drugs of apparently similar characteristics (e.g., high affinity full D1 agonists) can cause markedly different changes over time, in both in vitro cellular systems and the intact brain. Using site directed mutagenesis, a series of in vitro and in vivo system, and a powerful armamentarium of pharmacological probes, we shall seek to determine what aspects of receptor structure are important for regulatory events. In addition, we shall determine how co-activation of one or more populations of DA D2-like receptors affects long-term adaptive changes in vivo. These studies will not only be useful for heuristic reasons, but may affect the pending use of D1 agonists in several clinical conditions.