REGULATION OF HEART HIGH-ENERGY PHOSPHATE METABOLISM

这项提案的总体目标是进一步界定这些因素 在正常和缺血后的心脏中整合和调节 高能磷酸盐的生产，即三磷酸腺苷和 磷酸肌酸。这些代谢物的整合被认为是 肌酸激酶反应的功能。ATP的净产量是 线粒体氧化磷酸化的后果。这两个都是 在这份提案中将对流程进行调查。该模型是 分离、灌流、等容量工作兔心脏。分析性的 方法学将广泛涉及使用31-磷原子核 磁共振技术。动力学和热力学方法 将会被雇佣。为此，提出了三个具体目标： 1.饱和转移和二维核磁共振研究。这些生物物理技术 将被用来测量高能磷酸盐的通量速率 正常人和正常人的肌酸激酶和氧化磷酸化 缺血后心脏。目标是确定在多大程度上 缺血诱导的细胞损伤导致能量的根本变化 产学研结合。 2.体内呼吸控制研究。最近的研究表明， 腺嘌呤核苷酸对氧化磷酸化的调控与 腺苷二磷酸在线粒体腺嘌呤核苷酸转位酶上的可用性。 这一假说将在活体内使用起搏诱导的变化进行验证。 功能是以分级的方式对心肌施加压力。通过假设 胞浆形式的肌酸激酶处于“接近平衡”状态，人们可以使用 该反应计算游离态ADP的平衡常数 心满意足。然后，这将与利率的变化相关 以估算ADP诱导的表观Km 呼吸。 3.能源供需平衡：[Pcr]/[Pi]比值。这一比例现在是 被认为是新陈代谢供给量和 旺盛的需求。这将在灌流的心脏中使用 用于扰乱稳定状态的跳步协议。这在多大程度上 还将评估因缺血引起的细胞损伤而改变的平衡。 总体而言，这些基本研究将为我们提供对 正常和缺血者的动态和反应性生物能量状态 心肌。

The overall objective of this proposal is to further define those factors in the normal and post-ischemic heart which integrate and regulate the production of high-energy phosphate compounds, namely ATP and phosphocreatine. The integration of these metabolites is viewed to be the function of the creatine kinase reaction. The net production of ATP is the consequence of mitochondrial oxidative phosphorylation. Both of these processes will be investigated in this proposal. The model is the isolated, perfused, isovolumic working rabbit heart. The analytical methodology will extensively involve the use of 31-phosphorus nuclear magnetic resonance techniques. Both kinetic and thermodynamic approaches will be employed. To this end, three specific aims have been outlined: 1. Saturation transfer and 2-D NMR studies. These biophysical techniques will be used to measure the flux rates of high-energy phosphate mediated by creatine kinase and oxidative phosphorylation in the normal and post-ischemic heart. The goal will be to determine the degree to which ischemic induced cell damage results in fundamental changes in energy production and integration. 2. In vivo respiratory control studies. Recent studies have suggested that the adenine nucleotide control of oxidative phosphorylation relates to the availability of ADP at the mitochondrial adenine nucleotide translocase. This hypothesis will be tested in vivo using pace induced changes in function to stress the myocardium in a graded manner. By assuming that the cytoplasmic form of creatine kinase is in "near-equilibrium", one can use the equilibrium constant for this reaction to calculate the free ADP content of the heart. This will then be correlated to changes in the rates of oxygen consumption, to estimate the apparent Km for ADP induced respiration. 3. Energy supply/demand balance: The [PCr]/[Pi] ratio. This ratio is now thought to be an indication of the balance between metabolic supply and energetic demand. This will be explored in the perfused heart using the pace-jump protocol to perturb the steady state. The degree to which this balance is altered by ischemic induced cell damage will also be assessed. Overall, these fundamental studies will provide new insights into the dynamic and responsive bioenergetic status of both the normal and ischemic myocardium.