MOLECULAR STUDIES OF A NEW OPIOID RECEPTOR

阿片受体的三个主要类别，mu（mu），delta（delta）和kappa （kappa），已经基于其药理学的差异进行了定义， 生理学和组织分布。 当在体内受到刺激时， 受体激活一系列细胞内反应， 腺苷酸环化酶，钙通道和钾通道，这导致 阿片类药物中毒的许多典型效应， 欣快、镇痛和身体依赖。 分子 阿片样物质受体的表征一直很慢，由于几个 其中最重要的因素可能是， 难以溶解于活性物质中的内在膜蛋白 形式，并以相对较低的量表达。 最近这些 通过表达克隆小鼠δ基因克服了困难， 神经母细胞瘤X胶质瘤细胞系NG 108 - 1的阿片受体亚型 15. 主要的称为G蛋白偶联受体。 鉴于 这些最近的报告我们重新检查了孤儿受体的序列 我们通过简并PCR获得了一个克隆。 这个cDNA克隆， 作为R21，编码一种新的G蛋白偶联受体， 与最近发表的小鼠δ显著序列同一性 阿片受体 基于关键氨基酸残基的保守性 R21和小鼠δ阿片受体之间的整体同源性 我们预测R21是阿片受体家族的成员。 测试 我们提出这一假设， 研究其刺激对腺苷酸的影响， 环化酶和电压依赖性外向整流钾 电导 一旦确定，组织调节大鼠 R21基因将被表征。 R21基因的人类同源物将 也可以被表征以鉴定可用于遗传分析的标记物。 HR 21与人类疾病的关联研究。 最终 小鼠基因MR 21将被靶向并敲除。 这些转基因 小鼠将是一个有价值的模型系统，在其中评估受体的 在从突触传递到行为的过程中发挥作用。

Three major classes of opioid receptors, mu(mu), delta (delta) and kappa (kappa), have been defined based on differences in their pharmacology, physiology and tissue distribution. When stimulated in vivo the opioid receptors activate a cascade of intracellular reactions involving adenylyl cyclase, calcium channels and potassium channels, which result in many of the classical effects of opiate intoxication including euphoria, analgesia and physical dependence. The molecular characterization of the opioid receptors has been slow due to several factors, perhaps the most important of which being that they are intrinsic membrane proteins which are difficult to solubilize in active form and they are expressed in relatively low amounts. Recently these difficulties were overcome by the expression cloning of a mouse delta opioid receptor subtype from the neuroblastoma X glioma cell line NG108- 15. The primary known as the G protein-coupled receptors. In light of these recent reports we re-examined the sequence of an orphan receptor clone which we had obtained by degenerate PCR. This cDNA clone, referred to as R21, encodes a novel G protein-coupled receptor which shares significant sequence identity with the recently published mouse delta opioid receptor. Based on the conservation of key amino acid residues and the overall homology between R21 and the mouse delta opioid receptor we predict that R21 is a member of the opioid receptor family. To test this hypothesis we propose to pharmacologically characterize the receptor encoded by R21 and investigate the affect its stimulation has on adenylyl cyclase and a voltage-dependent outwardly rectifying potassium conductance. Once pharmacologically defined the tissue regulated the rat R21 gene will be characterized. The human homologue of the R21 gene will also be characterized to identify markers that can be used i genetic linkage and association studies of HR21 and human disease. Eventually the mouse gene, MR21, will be target and knocked out. These transgenic mice will be a valuable model system in which to evaluate the receptor's role in processes ranging from synaptic transmission to behavior.