DOPAMINE-LINKED PHOSPHOINOSITIDE METABOLISM IN BRAIN

描述：(申请人摘要)这是一份修订后的建议书 关于肌醇磷脂表征的NS29514计划的更新 连接的多巴胺(DA)受体。根据这笔赠款获得的证据支持 脑多巴胺受体亚型的存在与 肌醇磷脂第二信使途径。受体似乎是一种 D1/5样多巴胺受体，不同于经典定义的多巴胺 受体通过Gq蛋白与磷脂酶C偶联。这可能会 新的受体可能介导了一些生理和药理作用 腺酰环化酶不能解释的多巴胺效应 DA受体。因此，对反兴奋剂机构行动的理解是 通过该受体介导的药物在治疗和治疗中具有潜在的意义 诊断各种与DA相关的神经病理，包括 精神分裂症、帕金森氏症、亨廷顿舞蹈症和迟发性运动障碍。 鉴定这种受体蛋白的功能意义 在很大程度上依赖于成功地克隆出 对其进行编码。申请人S为此进行了初步努力，结果 唯一表达主体的细胞系的鉴定 研究人员连接的DA受体。获得这一细胞系有助于 克隆这一独特的DNA片段，它包含高度 在所有G蛋白偶联受体中保守。一系列实验 建议的具体目标如下：(A)继续并界定 大脑中由该受体启动的传递信号的组件 组织，(B)通过以下方式分离编码该受体的全长DNA 从人的DNA文库中筛选构建的DNA文库 细胞系，并测定其核苷酸序列和限制性内切酶图谱；c) 测定新药的组织分布和相对丰度 和(D)确定其配体结合和 G蛋白偶联结构域的表达和特性分析 受体的突变变种。这一项目的成果将为 为更好地理解DA在中枢神经系统中的作用奠定坚实的基础 功能和功能障碍，以及评估和可能重新定义各种 DA相关神经病理学的模型。

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.