PHARMACOLOGY OF CARDIAC A1 ADENOSINE RECEPTORS

拟议研究的主要目标是阐明 A1腺苷受体的分子结构和生物化学 参与信息转导的机制， 腺苷与受体的相互作用产生 细胞内信号 腺苷在正常条件下从细胞中释放， 病理生理条件，如缺血和缺氧，并可 与A1腺苷受体相互作用以直接抑制腺苷酸环化酶， 调节K+通道，减弱儿茶酚胺的作用，诱导 心动过缓和房室结阻滞，抑制脂肪分解和诱导镇静。 的 A1腺苷受体（A1 AR）与腺苷受体（A1 AR）的偶联机制和模式 各种效应器系统在很大程度上仍然是未知的。 哪种鸟嘌呤核苷酸 调节蛋白（G蛋白）的A1AR耦合，以及如何特异性和 这些不同途径的选择性仍然有待于 测定 这些研究将（1）完成A1AR的纯化 （2）研究纯化的A1AR在重组系统中的均一性， 从牛脑中纯化Gi和Go得到的G蛋白 和重组G蛋白（α亚基），（3）确定A1AR是否 是蛋白激酶的底物， 磷酸化，（4）开始确定参与的机制， A1AR与G蛋白的“紧密”偶联以及A1AR与哪些G蛋白的偶联 偶联和（5）从纯化的A1AR获得蛋白质序列数据 使用寡核苷酸杂交方法克隆A1AR。 这些 生物化学和分子生物学方法与体内方法是互补的， 动物和细胞培养受体调节和细胞生物学研究 目前正在主要研究者的实验室进行。 这项研究的最终目的是了解 和A1AR跨膜信号传导组分的功能 在健康和疾病中的装置，这样我们就可以操纵它， 成分的治疗益处。

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.