MOLECULAR STUDIES OF KAPPA OPIOID RECEPTORS

该提案寻求支持，以研究kappa阿片受体 分子、细胞、解剖学和药理学水平。这些受体 是内源性阿片类药物复杂系统的一部分 许多功能，包括疼痛调节和药物滥用。《卡帕》 受体是非常不寻常的，因为它们在没有 产生药物依赖。它们的激活导致了巨大的 一系列效果，从基本生理功能(如 水平衡)，到更复杂的大脑功能，如影响的变化 或者是感知。虽然这些受体的存在已经被证明是 在药理数据的基础上，它们的分子结构还没有 已澄清。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Delta阿片类药物的同源性 受体。我们已经证明了这个克隆有一个七跨膜 G蛋白偶联受体的典型结构，它结合 具有很高亲和力的一些经典的kappa配体和产物 前强啡肽前体。根据它的资料，我们对它进行了分类 作为kappa 1，并表明它被激动剂激活导致减少 在Forsklin刺激的cAMP水平上。我们已经证明了这一点 克隆在大脑中有一种组织表达模式，其特征是 Kappa 1站点。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kappa。 拟议的项目旨在完成克隆和克隆的任务 表征kappa受体家族的成员。Kappa受体 多样性是建立得很好的，尽管确切的站点数量是 不清楚，而且不同物种之间的差异非常显著。 因此，这项提案的一个主要目的是确定 Kappa受体在物种内和物种间的异质性。A相关 目的是充分描述这些受体的特性 药理概况，它们与内源性配体的相互作用，以及 它们与不同的信号转导途径相耦合。特别的 兴趣是这些受体的结构-功能决定因素，两者 在结合选择性和耦合机理方面。这将是 用分子技术研究用来产生特定突变体和 嵌合体。克隆的kappa受体的组织特异性表达 将详细分析，并特别注意接口 在这些受体和内源性配体之间。最后，最后一个目标 专注于通过长期接触这些受体来调节 阿片激动剂和拮抗剂，无论是kappa还是mu配体。 这些研究应该会提高我们对这些独特的受体和 阐明了它们所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.