ADENOSINE A1 AND A2 RECEPTORS IN THE MYOCARDIUM

描述（来自应用程序的逐字记录）：腺苷受体发挥作用， 调节心脏功能的重要作用。例如，腺苷Al 受体影响心脏节律、收缩和代谢，并介导缺血性心脏病。 预处理腺苷通过与腺苷A1受体相互作用是已知的 是抗肾上腺素的，因为它减少了收缩和代谢 心肌对β 1-肾上腺素能刺激的反应性。刺激 据报道，腺苷A2 a受体直接增加心脏 收缩性最近，我们报道了腺苷A2 a受体刺激， 也限制了腺苷的抗肾上腺素能作用。的机制 心脏腺苷A2 a受体不影响腺苷A1受体功能 知道的此外，尚不清楚A2 a受体作用是否也影响 其他受体的功能，如毒蕈碱受体功能。的 该项目的目的是研究分子机制， 腺苷A2 a受体抑制腺苷A1受体介导的 心脏中的抗肾上腺素作用。用大鼠心室肌细胞和心肌细胞 膜，拟议的研究应该揭示：1）腺苷 A2 a受体激活抑制由以下引起的抗肾上腺素能作用： 腺苷A1和毒蕈碱M2受体刺激，2）腺苷A1和毒蕈碱M2受体刺激的作用， A2 a受体对f31-肾上腺素能和腺苷A1配体结合的作用， β 1-肾上腺素能受体敏感腺苷酸环化酶活性，3） 蛋白激酶A和C、G蛋白激酶和受体的重要性 腺苷A2 a受体介导的腺苷磷酸化抑制 铝引起的抗肾上腺素能作用; 4）腺苷A2 a受体的作用 腺苷A1受体激活介导的GT3活性变化 β 1肾上腺素能受体刺激。从这些研究中获得的结果 应该提供关于腺苷分子功能的新信息 心肌中的受体此外，调查结果应显着 有助于我们对G蛋白分子机制的基础知识 心脏中的偶联受体交叉调节

DESCRIPTION (Verbatim from the application): Adenosine receptors play an important role in regulating cardiac function. For example, adenosine Al receptors affect heart rhythm, contraction and metabolism and mediate ischemic preconditioning. Adenosine by interacting with adenosine Al receptors is known to be antiadrenergic in that it reduces the contractile and metabolic responsiveness of the myocardium to beta1-adrenergic stimulation. Stimulation of adenosine A2a receptors has been reported to directly increase cardiac contractility. Recently we reported that adenosine A2a receptor stimulation also limits the antiadrenergic actions of adenosine. The mechanism by which the cardiac adenosine A2a receptors affect adenosine Al receptor function is not known. Furthermore, it is not known if A2a receptor actions also effect functioning of other receptors such as muscarinic receptor functioning. The objective of this project is to investigate the molecular mechanisms by which the adenosine A2a receptor inhibits adenosine Al receptor mediated antiadrenergic actions in the heart. Using rat ventricular myocytes and myocyte membranes, the proposed studies should reveal: 1) The way in which adenosine A2a receptor activation inhibits the antiadrenergic actions resulting from adenosine Al and muscarine M2 receptor stimulation, 2) The effect of adenosine A2a receptor action on f3 1-adrenergic, and adenosine Al ligand binding and beta1-adrenergic receptor sensitive adenylyl cyclase activity, 3) The importance of protein kinases A and C, G protein kinases, and receptor phosphorylation in the adenosine A2a receptor-mediated inhibition of adenosine Al-elicited antiadrenergic actions, and 4) The action of adenosine A2a receptor activation on adenosine Al receptor-mediated changes in GTPase activity upon beta1-adrenergic receptor stimulation. The results obtained from these studies should provide new information regarding the molecular functioning of adenosine receptors in the myocardium. Additionally, the findings should significantly contribute to our basic knowledge of the molecular mechanisms of G protein coupled receptor cross-regulation in the heart.