A3 RECEPTORS--CARDIOPROTECTIVE MECHANISMS

描述：(改编自《调查者摘要》) 修改了一位新调查员的拨款申请。这样做的目的是 建议研究A3腺苷受体的作用机制 (A3AR)对心肌缺血有保护作用，并研究其作用。 A3腺苷受体在心脏特异性耐药中的过表达 对缺血损伤和腺苷耐受性的发展。这个 假设A3腺苷受体通过 ATP依赖的钾通道(KATP)，涉及序列 Gi/o蛋白、PKC和MAPK通路的激活。使用A3腺苷 受体刺激的成年兔心肌细胞，将进行测量 PKC亚型，以及P44、P42、P38和JNK的激活。 特定的PKC异构体和MAPK通路将被阻断，并影响 对心肌保护的影响将在体外用缺血心肌细胞进行评估， 以及在活体内与梗塞的兔心。将使用这些相同的型号 百日咳毒素或特异性KATP通道阻滞剂的研究 Gi/o蛋白和KATP通道的作用。第二个假设是 转基因小鼠心脏A3腺苷受体的过度表达 将保护缺血和防止腺苷耐受性。最初， 心脏功能将通过生理、生化和 病理学研究。然后是对缺血损伤和腺苷的抵抗 耐受性将在小鼠脑梗塞模型和分离的 全心缺血的心脏模型。结果将为我们提供理解 A3腺苷受体的心脏保护机制，并可能 允许开发治疗缺血性心脏的分子策略 A3腺苷受体表达增加的疾病。

DESCRIPTION: (Adapted from the Investigator's Abstract) This is a revised grant application from a new investigator. The goal of this proposal is to study the mechanisms by which A3 adenosine receptors (A3AR) are cardioprotective for ischemia, and to study the effect of cardiac-specific overexpression of A3 adenosine receptors on resistance to ischemic injury and development of adenosine tolerance. The hypothesis is that A3 adenosine receptors provide cardioprotection via ATP-dependent potassium channels (KATP), involving the sequential activation of Gi/o proteins, PKC, and MAPK pathways. Using A3 adenosine receptor stimulated adult rabbit myocytes, measurements will be made of PKC isoforms, and activation of P44, P42, P38, and JNK will be examined. Specific PKC isoforms and MAPK pathways will be blocked, and the effect on cardioprotection will be assessed in vitro with ischemic myocytes, and in vivo with infarcted rabbit hearts. These same models will be used with pertussis toxin or with specific KATP channel inhibitors to study the role of Gi/o proteins and KATP channels. The second hypothesis is that cardiac A3 adenosine receptor overexpression in transgenic mice will protect from ischemia and prevent adenosine tolerance. Initially, cardiac function will be studied via physiology, biochemistry, and pathology studies. Then resistance to ischemic injury and to adenosine tolerance will be evaluated in a murine infarction model and an isolated heart model of global ischemia. The results will provide understanding of the mechanisms of A3 adenosine receptor cardioprotection, and may allow for development of molecular strategies to treat ischemic heart disease with increased expression of A3 adenosine receptors.