NOVEL MOLECULAR SITE FOR ANTIDOPAMINERGIC ACTION

描述（改编自申请人的摘要）：本发明的第一个目的 竞争性应用将是继续阐明分子基础 DA（特别是D1样）受体的配体识别， 这种相互作用的后果。 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），以完善 现有的模型，并测试替代绑定模型的假设， 这些受体。 这将通过基于结构的受体 建模和药物设计。 定点受体诱变， 可以探测突变的 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。 这反过来 然后可以用来测试和完善D1样受体的模型。 中 迭代的方式，我们将继续开发新的配体与新的 受体结合或激活机制，并对D1具有选择性 与D5受体相比。 这些配体将是继续研究的有力工具。 受体结构和功能的研究。 第二大方向 这项工作是为了了解药物-受体相互作用的后果。 虽然我们过去的工作提供了第一个完整的D1激动剂和一个完整的D1受体激动剂。 了解药物的分子特征， 内在的功效，目前还不清楚是什么分子机制产生充分的 与部分激动相比。 我们将确定激活的作用， G蛋白和转导系统的各种亚型，以确定是否 部分激动作用是定量的或根据激活分级的：（1） G蛋白的个体群体;和2）各种转导系统 （尤其是腺苷酸环化酶）。 最后，我们将研究分子 脱敏和下调机制。 尽管 对其他G蛋白系统中这些现象的广泛了解，我们 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）可随时间引起显著不同的变化， 在体外细胞系统和完整的大脑中。 使用定点 诱变，一系列的体外和体内系统，和一个强大的 药理学探针，我们将寻求确定什么 受体结构的各个方面对于调节事件是重要的。 在 此外，我们将确定如何共激活一个或多个人口的 DA D2样受体影响体内的长期适应性变化。 这些 研究将不仅是有益的启发性的原因，但可能会影响 D1激动剂在几种临床条件下的应用。

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.