Effect of Drugs on Myocardial Hypoxia

描述（由申请人提供）：本研究提案的目的是检查阿片受体激动剂在再灌注时给药和作为慢性治疗给药时提供缺血/再灌注损伤保护的机制。我们假设δ和κ阿片受体激动剂在再灌注前通过激活包括PI 3 K/akt/GSKbeta/ERK 1/2轴（再灌注损伤补救激酶或RISK通路）在内的促存活信号通路来提供心脏保护。对于慢性治疗，我们假设持续的心脏保护作用由两种互补机制介导：1）上调心脏保护蛋白，包括12-LO、iNOS和考克斯-2（延迟诱导补救途径或DISP途径），2）诱导β-2肾上腺素能受体，导致腺苷酸环化酶抑制。总之，我们预测ATP敏感性钾（KATP）通道的肌膜亚型是阿片受体诱导的心脏保护的触发器，而线粒体KATP通道是阿片受体诱导的心脏保护的末端效应器。我们的研究涉及使用在体内大鼠/小鼠模型的梗死和离体小鼠心脏模型的全脑缺血和再灌注，其中梗死面积和左心室收缩功能的恢复被用作缺血性损伤的指标，分别。将通过使用选择性药理学探针、基因“敲除”小鼠、蛋白质免疫印迹、放射性配体结合分析以及记录肌膜（分离心肌细胞的膜片钳记录）和线粒体（记录线粒体脂质双层中的KATP通道电流）KATP通道电流来评估特定信号通路、心脏保护蛋白和受体亚型的参与。总的来说，这些研究结合了联合收割机最先进的技术，提供了关于阿片受体激动剂提供缺血/再灌注损伤保护机制的新信息。从这些研究中获得的信息将有望导致新的治疗方法来治疗缺血性心脏病患者。

DESCRIPTION (provided by applicant): The goal of this research proposal is to examine mechanisms by which opioid receptor agonists provide protection from ischemia/reperfusion injury when administered at the time of reperfusion and when administered as chronic therapy. We hypothesize that delta and kappa opioid receptor agonists confer cardioprotection when administered prior to reperfusion by activating pro-survival signaling pathways including the PI3K/akt/GSKbeta/ERK 1/2 axis (reperfusion injury salvage kinases or the RISK pathway). With chronic therapy, we hypothesize that sustained cardioprotection is mediated by two complementary mechanisms: 1) up-regulation of cardioprotective proteins including 12-LO, iNOS, and COX-2 (delayed inducible salvage pathway or the DISP pathway), and 2) induction of beta-2 adrenergic receptors resulting in inhibition of adenylyl cyclase. Overall, we predict that the sarcolemmal isoform of the ATP-sensitive potassium (KATP) channel is the trigger and the mitochondrial KATP channel is the end-effector of opioid receptor-induced cardioprotection. Our studies involve the use of an in vivo rat/mouse model of infarction and an isolated mouse heart model of global ischemia and reperfusion in which infarct size and recovery of left ventricular contractile function are used as indices of ischemic injury, respectively. The involvement of specific signaling pathways, cardioprotective proteins, and receptor subtypes will be assessed by using selective pharmacological probes, gene "knock-out" mice, Western immunoblotting, radioligand binding analysis, and recording of sarcolemmal (patch clamp recordings of isolated cardiac myocytes) and mitochondrial (recordings of KATP channel currents in mitochondrial lipid bi-layers) KATP channel currents. Collectively, these studies combine state-of-the-art techniques to provide new information regarding mechanisms by which opioid receptor agonists provide protection from ischemia/reperfusion injury. Information gained from these studies will hopefully lead to new therapies to treat patients with ischemic heart disease.