MOLECULAR STUDIES OF KAPPA OPIOID RECEPTORS

这项提案寻求支持，以研究κ阿片受体在 分子、细胞、解剖学和药理学水平。这些受体 是内源性阿片样物质复杂系统的一部分， 包括疼痛调节和药物滥用在内的多种功能。卡帕 受体非常不寻常，因为它们介导疼痛缓解， 产生药物依赖。它们的激活导致了 一系列的影响，从基本的生理功能（如 水平衡），更复杂的大脑功能，如影响 或感知。虽然这些受体的存在已经在 药理学数据的基础上，他们的分子结构还没有被 阐明。我们最近克隆了这个kappa家族的一个成员， 大鼠脑文库，基于与新克隆的δ阿片样物质的同源性 受体的我们已经证明，这个克隆有一个七跨膜 结构典型的G蛋白偶联受体，它结合 与许多经典的κ配体和产物具有高亲和力 前强啡肽的前体根据它的外形，我们把它归类为 并显示其被激动剂激活导致 毛喉素刺激的环磷酸腺苷水平。我们已经证明， 克隆在大脑中具有以下特征的组织表达模式： Kappa 1网站我们还从几内亚获得了两个相关的克隆 猪，我们暂时将其归类为卡帕。 拟议的项目旨在完成克隆任务， 表征κ受体家族的成员。κ受体 多样性是公认的，虽然网站的确切数量是 不清楚，不同物种之间的差异非常惊人。 因此，本提案的一个主要目的是确定 种内和种间的κ受体异质性。一个相关 目的是充分表征这些受体在其 药理学特征，它们与内源性配体的相互作用，以及 它们与各种信号转导途径的偶联。特别 感兴趣的是这些受体的结构-功能决定因素， 在结合选择性和偶联机制方面。这将是 用分子技术研究，用来产生特定的突变体， 嵌合体克隆κ受体的组织特异性表达 将详细研究，特别注意接口 在这些受体和内源性配体之间。最后，最后一个目标 是集中在这些受体的调制长期暴露于 阿片激动剂和拮抗剂，它们是κ或μ配体。 这些研究应该提高我们对这些独特受体的认识， 阐明了他们参与的一些关键机制， 包括疼痛控制、奖励和厌恶以及药物滥用。

This proposal seeks support to study kappa opioid receptors at the molecular, cellular, anatomical and pharmacological level. These receptors are part of the complex system of endogenous opioids which modulates numerous functions including pain regulation, and drug abuse. The kappa receptors are highly unusual since they mediate pain relief without producing drug dependence. Their activation is responsible for a vast array of effects, ranging from basic physiological functions (such as water balance), to more complex brain functions such as changes in affect or perception. While the existence of these receptors has been shown on the basis of pharmacological data, their molecular structure had not been elucidated. We have recently cloned a member of this kappa family from a rat brain library, based on homology to the newly cloned delta opioid receptor. We have shown that this clone has a seven transmembrane structure typical of the G-protein coupled receptors, and that it binds with high affinity a number of classical kappa ligands and to the products of the prodynorphin precursor. Based on its profile, we have classified it as kappa 1 and shown that its activation by agonists leads to a decrease in forskolin-stimulated cyclic AMP levels. We have demonstrated that this clone has a pattern of tissue expression in the brain characteristic of the kappa 1 site. We have also obtained two related clones from guinea pig, which we tentatively classify as kappa. The proposed project is aimed at completing the task of cloning and characterizing members of the kappa receptor family. Kappa receptor multiplicity is well established, although the exact number of sites is not clear, and the differences across species are very striking. Consequently, a major aim of this proposal is to determine the extent of kappa receptor heterogeneity both within and across species. A related purpose is to fully characterize these receptors in terms of their pharmacological profile, their interactions with endogenous ligands, and their coupling to various signal transduction pathways. Of particular interest is the structure-function determinants of these receptors, both in terms of binding selectivity and coupling mechanisms. This will be studied with molecular techniques used to generate specific mutants and chimeras. The tissue-specific expression of the cloned kappa receptors will be examined in detail, with particular attention to the interface between these receptors and the endogenous ligands. Finally, the last aim is focused on the modulation of these receptors by long-term exposure to opiate agonists and antagonists, be they kappa or mu ligands. These studies should improve our knowledge of these unique receptors and shed light on a number of key mechanisms in which they are involved including pain control, reward and aversiveness, and drug abuse.