Gard J K, Kichura G M, Ackerman J J, Eisenberg J D, Billadello J J, Sobel B E, Gross R W
Biophys J. 1985 Nov;48(5):803-13. doi: 10.1016/S0006-3495(85)83839-X.
The quantitative analysis of the mobile high-energy phosphorus metabolites in isovolumic Langendorff-perfused rabbit hearts has been performed by 31P NMR utilizing rapid pulse repetition to optimize sensitivity. Absolute quantification required reference to an external standard, determination of differential magnetization saturation and resonance peak area integration by Lorentzian lineshape analysis. Traditionally accepted hemodynamic indices (LVDP, dp/dt) and biochemical indices (lactate, pyruvate) of myocardial function were measured concomitantly with all NMR determinations. Hemodynamically and biochemically competent Langendorff-perfused rabbit hearts were found to have intracellular PCr, ATP, GPC, and Pi concentrations of 14.95 +/- 0.25, 8.08 +/- 0.13, 5.20 +/- 0.58 and 2.61 +/- 0.47 mM respectively. Intracellular pH was 7.03 +/- 0.01. Cytosolic ADP concentration was derived from a creatine kinase equilibrium model and determined to be approximately 36 microM. Reduction of perfusate flow from 20 to 2.5 ml/min demonstrated statistically significant decreases in PCr, ATP, and pH as well as an increase in Pi that correlated closely with the independent hemodynamic and biochemical indices of myocardial function. The decrease in ATP and PCr concentrations precisely matched the increase in Pi during reduced flow. These results constitute the first quantitative determination of intracellular metabolite concentrations by 31P NMR in intact rabbit myocardium under physiologic and low flow conditions.
利用快速脉冲重复技术优化灵敏度，通过31P核磁共振对等容Langendorff灌注兔心脏中的可移动高能磷代谢物进行了定量分析。绝对定量需要参考外部标准，通过洛伦兹线形分析确定微分磁化饱和度和共振峰面积积分。在所有核磁共振测定的同时，测量了传统上认可的心肌功能血液动力学指标（左心室舒张末期压力、dp/dt）和生化指标（乳酸、丙酮酸）。发现血液动力学和生化功能正常的Langendorff灌注兔心脏的细胞内磷酸肌酸（PCr）、三磷酸腺苷（ATP）、甘油磷酸胆碱（GPC）和无机磷（Pi）浓度分别为14.95±0.25、8.08±0.13、5.20±0.58和2.61±0.47 mM。细胞内pH值为7.03±0.01。胞质二磷酸腺苷（ADP）浓度通过肌酸激酶平衡模型推导得出，约为36 microM。将灌注液流量从20 ml/min降至2.5 ml/min，结果显示PCr、ATP和pH值有统计学意义的下降，以及Pi的增加，这与心肌功能的独立血液动力学和生化指标密切相关。在流量降低期间，ATP和PCr浓度的下降与Pi的增加精确匹配。这些结果是在生理和低流量条件下，首次通过31P核磁共振对完整兔心肌细胞内代谢物浓度进行的定量测定。
