PHARMACOLOGY OF CARDIAC A1 ADENOSINE RECEPTORS

拟议研究的主要目标是阐明 腺苷A1受体的分子结构与生化 参与信息传递的机制(S) 腺苷与受体的相互作用 细胞内信号。腺苷在正常和正常情况下从细胞释放 病理生理状态，如缺血和缺氧，并可 与A1腺苷受体相互作用直接抑制腺苷环化酶， 调节K+通道，钝化儿茶酚胺的作用，诱导 心动过缓和房室结阻滞，抑制脂解和诱导镇静。这个 A1腺苷受体(A1AR)与细胞的偶联机制和方式 各种效应器系统在很大程度上仍然未知。哪种鸟嘌呤核苷酸 A1AR偶联的调节蛋白(G蛋白)以及特异性和 对这些不同的途径保持选择性有待于 下定决心。这些研究将(1)完成A1AR的纯化 为了均一，(2)研究了重建系统中纯化的A1AR 从牛脑中分离纯化GI和GO的G蛋白 并用重组G蛋白(α亚基)，(3)测定A1AR 是蛋白激酶的底物，其功能结果是 磷酸化，(4)开始查明参与的机制 A1AR与G蛋白的“紧密”偶联以及哪些G蛋白是A1AR 偶联到和(5)以从纯化的A1AR中获得蛋白质序列数据 用寡核苷酸杂交法克隆A1AR。这些 生化和分子生物学方法是对活体的补充 动物和细胞培养受体调控与细胞生物学研究 目前正在首席调查员的实验室进行。 拟议研究的最终目标是了解结构 A1AR跨膜信号转导的组成和功能 健康和疾病方面的仪器，这样我们就可以操纵它 用于治疗益处的成分。

The major goals of the proposed research are the elucidation of the molecular structure of the A1 adenosine receptor and the biochemical mechanism(s) involved in the transduction of information from the interaction of adenosine with the receptor to the production of intracellular signals. Adenosine is released from cells under normal and pathophysiological conditions, such as ischemia and hypoxia and can interact with A1 adenosine receptors to directly inhibit adenylate cyclase, modulate K+ channels, blunt the effect of catecholamines, induce bradycardia and AV nodal block, inhibit lipolysis and induce sedation. The mechanisms and mode of coupling of the A1 adenosine receptor (A1AR) to the various effector systems remain largely unknown. Which guanine nucleotide regulatory proteins (G proteins) the A1AR couple to and how specificity and selectivity are maintained for these diverse pathways remains to be determined. These studies will (1) complete the purification of the A1AR to homogeneity, (2) study the purified A1AR in reconstitution systems with G proteins derived from both purification of Gi and Go from bovine brain and with recombinant G protein (alpha subunits), (3) determine if the A1AR is a substrate for protein kinases and the functional consequences of phosphorylation, (4) begin to ascertain the mechanisms involved in the "tight" coupling of A1AR with G proteins and which G proteins the A1AR couples to and (5) to obtain protein sequence data from the purified A1AR to clone the A1AR using an oligonucleotide hybridization approach. These biochemical and molecular biologic approaches are complimentary to in vivo animal and cell culture receptor regulation and cell biology studies currently ongoing in the Principal Investigator's laboratory. The ultimate goal of the proposed research is to understand the structure and function of the components of the A1AR transmembrane signalling apparatus both in health and disease so that we can manipulate its components for therapeutic benefit.