STRUCTURE/FUNCTION ANALYSIS OF OPIOID RECEPTOR SUBTYPES

药物成瘾是一种慢性复发性脑部疾病 表现为各种行为，这是有害的， 个人和社会。 对神经生物学的理解 成瘾需要了解大脑的功能 以及阿片类药物如何改变大脑功能， 上瘾的过程。 阿片类药物的作用是通过 脑细胞表面的阿片受体。 分子 从阿片样物质的三种主要亚型克隆cDNA 受体，μ，δ和κ，开辟了新的途径， 阿片受体激活和信号转导途径。 虽然关于受体的一般性质的预测 根据阿片类物质的结构， 生物碱和肽，特定结构域和氨基的作用， 最近已经研究了用于适当受体功能的酸残基 使用体外诱变的方法， 受体嵌合体的分析。 这项建议旨在确定 关键的结构决定因素，包括表面的 μ和δ受体的配体结合裂缝，并鉴定 负责这些配体选择性的残基 受体亚型 我们确定他的223亩 受体是配体识别的关键，是一个可能的位点， NEM烷基化反应将进一步研究。 的假设 泛素化参与配体依赖的内吞作用， 测试. 此外，受体内的氨基酸， 负责G蛋白的激活和受体介导的 将表征内吞作用。 这项研究将直接 对长期目标的影响，以了解在分子 水平阿片受体如何与其配体相互作用并激活 导致细胞反应的信号转导途径。 是 预计，分子和细胞研究的影响， 本申请中提出的阿片类药物和肽将有助于 阐明耐受性所涉及的机制， 对阿片类药物的身体依赖

Drug addiction is a chronic relapsing disease of the brain manifested by a variety of behaviors that are detrimental to both the individual and society. An understanding of the neurobiology of addiction will require knowledge about how the brain functions normally and how opioid drugs alter brain functioning over the course of addiction. Opioid drugs initiate their effects by engaging opioid receptors on the cell surface of brain cells. The molecular cloning of cDNAs from the three major subtypes of opioid receptors, mu, delta and kappa, has opened new avenues to study opioid receptor activation and signal transduction pathways. Although predictions about the general nature of the receptor binding site have been made based on the structures of opioid alkaloids and peptides, the role of particular domains and amino acid residues for proper receptor function has been recently studies using the methodology of in vitro mutagenesis in conjunction with analysis of receptor chimeras. This proposal seeks to identify the critical structural determinants that comprise the surface of the ligand binding crevice for the mu and delta receptor, and to identify the residues that are responsible for the ligand selectivity of these receptor subtypes. Our determination that His223 of the mu receptor is critical for ligand recognition and is a possible site for NEM alkylation will be further investigated. The hypothesis that ubiquitination is involved in ligand-dependent endocytosis will be tested. In addition, amino acids within the receptor that are responsible for activation of G proteins and receptor-mediated endocytosis will be characterized. This research will have a direct impact on the long-term objective to understand at the molecular level how opioid receptors interact with their ligands and activate signal transduction pathways that result in cellular responses. It is anticipated that the molecular and cellular studies of the effects of opioid drugs and peptides proposed in this application will aid in the elucidation of the mechanisms involved in tolerance to, and physical dependence on, opioids.