Cole R P, Wittenberg B A, Caldwell P R
Am J Physiol. 1978 May;234(5):H567-72. doi: 10.1152/ajpheart.1978.234.5.H567.
An isolated dog heart preparation perfused with hemoglobin-free fluorocarbon suspension has been developed to study the role of myoglobin in myocardial function. The coronary vasculature was perfused at constant flow, with oxygen consumption determined from arteriovenous PO2 differences. Muscle function was assessed by measurement of pressures generated in a latex balloon placed in the left ventricle. The perfusate consisted of 20% perfluorotributylamine and 80% Ringer's lactate with 16 mM glucose. Steady-state oxygen consumption decreased from 0.30 to 0.11 ml/min per gram dry weight left ventricle, as perfusate PO2 decreased from 690 to 150 mmHg. Left ventricular pressure generation and oxygen consumption were determined before and after addition of 8 mM sodium nitrite, which changed functional ferrous myoglobin to high-spin ferric myoglobin. Over the range of perfusate PO2 studied, nitrite addition did not alter mechanical performance or myocardial oxygen consumption. These data suggest that those conditions necessary for substantial myoglobin-facilitated diffusion of oxygen in the myocardium are not present in the isolated fluorocarbon-perfused dog heart.
一种用不含血红蛋白的氟碳悬浮液灌注的离体犬心制备方法已被开发出来，用于研究肌红蛋白在心肌功能中的作用。冠状动脉系统以恒定流量灌注，通过动静脉氧分压差值测定耗氧量。通过测量置于左心室内的乳胶气球产生的压力来评估肌肉功能。灌注液由20%的全氟三丁胺和80%含16 mM葡萄糖的乳酸林格氏液组成。随着灌注液氧分压从690 mmHg降至150 mmHg，每克左心室干重的稳态耗氧量从0.30 ml/min降至0.11 ml/min。在添加8 mM亚硝酸钠（将功能性亚铁肌红蛋白转变为高自旋铁肌红蛋白）之前和之后，测定左心室压力产生和耗氧量。在所研究的灌注液氧分压范围内，添加亚硝酸盐并未改变机械性能或心肌耗氧量。这些数据表明，在离体氟碳灌注犬心中不存在大量肌红蛋白促进心肌氧扩散所需的条件。
