RESPONSES OF SUBPOPULATIONS OF MUSCARINIC RECEPTORS

毒蕈碱受体亚群的反应

• 批准号: 6533725
• 负责人: JOHN ELLIS
• 金额: $ 21.08万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-02-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6533725
• 关键词: Alzheimer's disease; acetylcholine; allosteric site; cell line; chemical binding; chemical structure function; chimeric proteins; gallamine triethiodide; gene mutation; inhibitor /antagonist; intermolecular interaction; ligands; mathematical model; molecular genetics; muscarinic receptor; neuropharmacology; protein structure function; radiotracer; receptor binding; receptor sensitivity; site directed mutagenesis; stimulant /agonist; tissue /cell culture; transfection; Alzheimer's disease; acetylcholine; allosteric site; cell line; chemical binding; chemical structure function; chimeric proteins; gallamine triethiodide; gene mutation; inhibitor /antagonist; intermolecular interaction; ligands; mathematical model; molecular genetics; muscarinic receptor; neuropharmacology; protein structure function; radiotracer; receptor binding; receptor sensitivity; site directed mutagenesis; stimulant /agonist; tissue /cell culture; transfection

DESCRIPTION(Adapted from applicant's abstract): Muscarinic acetylcholine receptors belong to the very numerous class of heptahelical-receptors, but are unusual for this class in that they possess multiple extracellular binding sites. The present studies are designed to better understand muscarinic allosteric interactions from pharmacological and structural viewpoints. Dysfunction of muscarinic cholinergic systems in the brain contributes to the deficits associated with many illnesses, including Alzheimer's Disease. However, treatment with directly-acting muscarinic cholinergic drugs has not proven to be very beneficial to date. This may relate in part to the adverse effects and lack of selectivity of currently available muscarinic drugs. There are theoretical reasons why allosteric drugs can have inherent advantages of selectivity, efficacy, and safety over directly-acting (competitive) agents. For example, the allosterically-acting benzodiazopines enhance the action of the neurotransmitter GABA and are very effective and safe, even though directly-acting GABA agonists and reuptake inhibitors have no clinical use whatsoever. Although it has been known for some time that muscarinic receptors are susceptible to allosteric regulation only very recently have allosteric ligands been discovered that are positively cooperative with the endogenous agonist, acetylcholine. These first-generation ligands have relatively low affinities, but they demonstrate a potential for the development of drugs that are subtype-selective in terms of cooperativity, as well as affinity. The aims of this application are to apply approaches that we have developed in past studies to better understand the interactions between the receptors and allosteric ligands, especially these new ligands. These tools include: pharmacological model testing, to determine whether ligands interact solely with an allosteric site and whether different allosteric ligands act at a common site; and, molecular genetic techniques, to determine which structural features of the receptors are responsible for the subtype-selective binding and cooperativity of allosteric ligands. The hypothesis behind all of these studies is that subtype-selective ligands interact with specific residues that can be located through the use of mutagenic and chimeric studies. Once candidate residues have been identified by this process, the hypothesis that they are in fact involved in intimate contact with the ligand will be tested by making reciprocal mutations on different subtypes, by investigating the interaction of modified ligands with wild-type and modified receptors, and by inserting specific epitopes into non-muscarinic receptors. We expect that the results of these studies will benefit cholinergic pharmacology and also contribute to an understanding of the potential for allosteric modulation of other heptahelical receptors.

描述（根据申请人的摘要改编）： 毒蕈碱乙酰胆碱受体属于非常众多的一类 七螺旋体受体，但对此班级来说是不寻常的 多个细胞外结合位点。目前的研究旨在 更好地了解药理学和 结构观点。毒蕈碱胆碱能系统功能障碍 大脑会导致与许多疾病相关的缺陷，包括 阿尔茨海默氏病。但是，直接作用的毒蕈碱治疗 迄今为止，胆碱能药物尚未非常有益。这可能是相关的 部分涉及当前可用的不良影响和缺乏选择性 毒蕈碱药物。理论上的原因是变构药物可以 选择性，疗效和安全性的固有优势而不是直接作用 （竞争）代理。例如，变构作用苯二氮卓类药物 增强神经递质GABA的作用，非常有效，并且 安全，即使直接作用的GABA激动剂和再摄取抑制剂没有 临床用途。尽管已经知道了一段时间 毒蕈碱受体仅对变构调节敏感 最近发现有变构配体是积极的 与内源激动剂乙酰胆碱合作。这些第一代 配体的亲和力相对较低，但它们证明了 从合作性角度开发亚型选择性的药物， 以及亲和力。本应用程序的目的是应用 我们已经在过去的研究中发展了，以更好地了解 受体和变构配体，尤其是这些新的配体。这些工具 包括：药理模型测试，确定配体是否相互作用 仅使用变构位点，以及不同的变构配体在 一个共同的地点；以及分子遗传技术，以确定哪种结构 受体的特征负责亚型选择性结合和 变构配体的合作性。所有这些研究背后的假设 是亚型选择配体与可能是的特定残基相互作用 通过使用诱变和嵌合研究。一旦候选人 该过程已经确定了残留物，这是它们所在的假设 与配体亲密接触涉及的事实将通过制作测试 通过研究的相互作用 带有野生型和修饰受体的修饰配体，并通过插入 特异性表位成非毒桃体受体。我们希望结果 这些研究将使胆碱能药理学受益，并有助于 了解其他七旋赫利克的变构调节的潜力 受体。