Van Beek J H, Westerhof N
Laboratory for Physiology, Free University, Amsterdam, The Netherlands.
Am J Physiol. 1991 Feb;260(2 Pt 2):H613-25. doi: 10.1152/ajpheart.1991.260.2.H613.
We investigated the time course of cardiac mitochondrial O2 consumption following steps in heart rate in 16 isolated rabbit hearts perfused with Tyrode solution. The time course was characterized by the mean response time, i.e., the first statistical moment (mean time) of the impulse response function. Like the mean transit time for an indicator, it provides an important characteristic of the response time course. The venous O2 content transients during steps in heart rate were measured and corrected for O2 diffusion and vascular transport using a mathematical model with experimental information derived from O2 washout following steps in arterial O2 concentration or perfusion flow. We deduce from these washout experiments that the effective O2 solubility in heart tissue is 86 +/- 13% (mean +/- SE) of solubility in water. The measured venous mean response time following a step in heart rate at 37 degrees C was 17.6 +/- 1.1 s. The mean response time of cardiac mitochondrial O2 consumption to changes in heart rate after correction for O2 transport was 7.7 +/- 0.7 s.
我们在16个用台氏液灌注的离体兔心脏中，研究了心率变化后心脏线粒体氧气消耗的时间进程。该时间进程以平均反应时间为特征，即脉冲响应函数的一阶统计矩（平均时间）。与指示剂的平均通过时间一样，它提供了反应时间进程的一个重要特征。在心率变化过程中测量静脉血氧含量瞬变，并使用一个数学模型对氧气扩散和血管运输进行校正，该模型的实验信息来自于动脉血氧浓度或灌注流量变化后的氧气洗脱实验。我们从这些洗脱实验中推断，心脏组织中有效氧溶解度是水中溶解度的86±13%（平均值±标准误）。在37℃时心率变化后测得的静脉平均反应时间为17.6±1.1秒。校正氧气运输后，心脏线粒体氧气消耗对心率变化的平均反应时间为7.7±0.7秒。
