DOPAMINE-LINKED PHOSPHOINOSITIDE METABOLISM IN BRAIN

描述：（申请人的摘要）这是一个修订的建议， 更新关于磷酸肌醇表征的项目NS 29514 多巴胺（DA）受体。 根据该补助金获得的证据支持 大脑DA受体亚型的存在，这是连接到 磷酸肌醇第二信使途径。 受体似乎是一种 D1/5样DA受体，不同于经典定义的多巴胺 受体通过Gq蛋白偶联至磷脂酶C。 这潜在地 新的受体可能介导一些生理和药理学的 腺苷酸环化酶相关的DA不能解释DA的作用。 DA受体。 因此，对DA行动的理解是， 通过这种受体介导的药物具有潜在的治疗意义， 诊断各种DA相关神经病理学，包括 精神分裂症、帕金森综合征、亨廷顿舞蹈病和迟发性运动障碍。 表征这种受体蛋白的功能意义将 在很大程度上取决于cDNA的成功克隆， 编码。申请人为此所做的初步努力导致了 鉴定仅表达主要的 多巴胺受体。 获得这种细胞系有助于 克隆这个独特的DNA片段，它含有高度 在所有G蛋白偶联受体中是保守的。 一系列实验 建议的具体目标如下：（a）继续并确定 大脑中传递由该受体启动的信号的成分 组织，（B）分离编码该受体的全长DNA， 筛选从人cDNA或从选择的人cDNA构建的DNA文库， 细胞系，并确定其核苷酸序列和限制性酶切图谱; c） 确定新的组织分布和相对丰度 受体信息，以及（d）鉴定其配体结合， G蛋白偶联结构域的表达和特征分析 受体的变异体。 该项目的成果将奠定 为更好地理解DA在CNS中的作用奠定了坚实的基础 功能和功能障碍，并评估和可能重新定义各种 DA相关神经病理学模型。

DESCRIPTION: (Applicant's abstract) This is a revised proposal for a renewal of project NS29514 on the characterization of the phosphoinositide linked dopamine (DA) receptor. Evidence obtained under this grant supports the existence of the brain DA receptor subtype which is linked to the phosphoinositide second messenger pathway. The receptor appears to be a D1/5 like DA receptor, differing from the classically defined dopamine receptor by coupling to phospholipase C via Gq protein. This potentially novel receptor may mediate some of the physiological and pharmacological effects of DA which cannot be accounted for by the adenylyl cyclase-linked DA receptors. Consequently, the understanding of the actions of DA that are mediated via this receptor has potential implications for therapeutics and diagnosis of various DA-associated neuropathologies, including schizophrenia, Parkinsonism, Huntington's chorea and tardive dyskinesia. Characterizing the functional significance of this receptor protein will depend, to a large extent, on the successful cloning of the cDNA which encodes it. The applicant s preliminary efforts to this end resulted in the identification of a cell line which exclusively expresses the principal investigator-linked DA receptor. Obtaining this cell line facilitated the cloning of this unique DNA fragment which contains elements that are highly conserved among all G-protein coupled receptors. A series of experiments are proposed with the following specific aims: (a) to continue and define the components which transduce signals initiated by this receptor in brain tissue, (b) to isolate the full length DNA which encodes this receptor by screening a DNA library constructed from a human cDNA or from the selected cell line, and determine its nucleotide sequence, and restriction map; c) determine the tissue distribution and relative abundance of the novel receptor message in rat brain, and (d) identify its ligand binding and G-protein coupling domains by expressing and analyzing the characteristics of mutant variants of the receptor. The results of this project will lay a solid foundation for the greater understanding of the role of DA in CNS function and dysfunction, and for evaluating and possibly redefining various models of DA-associated neuropathologies.