Oxygen dependence of respiration in rat spinotrapezius muscle in situ
Oxygen dependence of respiration in rat spinotrapezius muscle in situ
复制标题
DOI：
10.1152/ajpheart.00131.2012
复制
发表时间：
2012-07-01
影响因子：
4.8
通讯作者：
Pittman, Roland N.
中科院分区：
文献类型：
--
作者：
Golub, Aleksander S.;Pittman, Roland N.
Golub AS, Pittman RN。大鼠斜方肌原位呼吸的氧依赖性。[J]中国生物医学工程学报，2016,31(2):447 - 456。首次发表于2012年4月20日；doi: 10.1152 / ajpheart.00131.2012。-通过测量间质Po-2[氧消失曲线（ODC）]在气动组织压缩快速停止血流后的降低率，研究了横纹肌原位呼吸的氧依赖性。气动组织压缩将红细胞从肌肉血管中喷射出来，使ODC独立于与血红蛋白结合的氧气。在计算了该方法对光耗氧的贡献后，将校正后的ODCs转化为对Po-2的依赖，即Vo(2)，与Po-2的降低速率成正比。从异质细胞内Po-2模型获得的拟合方程应用于恢复描述肌肉纤维呼吸的参数，预测Vo(2)对Po-2的依赖呈s形。该曲线由两个由细胞临界Po-2点（即细胞中心缺氧时肌膜处的Po-2）连接的区域组成。细胞半最大呼吸速率（P-50）的临界Po-2低于Po-2。在6块肌肉休息时，耗氧量为139 +/- 6 nl O-2/cm(3)。线粒体P-50 k = 10.5 +/- 0.8 mmHg。肌纤维内Po-2的临界值范围为4-5毫米汞柱。在不同的实验条件下，可以研究薄肌肉的呼吸对氧的依赖。在静息肌肉中，临界Po-2明显低于53 +/- 2 mmHg的间质Po-2，这一发现表明在这种情况下Vo(2)不依赖于供氧，与代谢调节组织供氧的传统假设不一致。
Golub AS, Pittman RN. Oxygen dependence of respiration in rat spinotrapezius muscle in situ. Am J Physiol Heart Circ Physiol 303: H47-H56, 2012. First published April 20, 2012; doi: 10.1152/ajpheart.00131.2012.-The oxygen dependence of respiration in striated muscle in situ was studied by measuring the rate of decrease of interstitial Po-2 [oxygen disappearance curve (ODC)] following rapid arrest of blood flow by pneumatic tissue compression, which ejected red blood cells from the muscle vessels and made the ODC independent from oxygen bound to hemoglobin. After the contribution of photo- consumption of oxygen by the method was evaluated and accounted for, the corrected ODCs were converted into the Po-2 dependence of oxygen consumption, Vo(2), proportional to the rate of Po-2 decrease. Fitting equations obtained from a model of heterogeneous intracellular Po-2 were applied to recover the parameters describing respiration in muscle fibers, with a predicted sigmoidal shape for the dependence of Vo(2) on Po-2. This curve consists of two regions connected by the point for critical Po-2 of the cell (i.e., Po-2 at the sarcolemma when the center of the cell becomes anoxic). The critical Po-2 was below the Po-2 for half- maximal respiratory rate (P-50) for the cells. In six muscles at rest, the rate of oxygen consumption was 139 +/- 6 nl O-2/cm(3).s and mitochondrial P-50 was k = 10.5 +/- 0.8 mmHg. The range of Po-2 values inside the muscle fibers was found to be 4-5 mmHg at the critical Po-2. The oxygen dependence of respiration can be studied in thin muscles under different experimental conditions. In resting muscle, the critical Po-2 was substantially lower than the interstitial Po-2 of 53 +/- 2 mmHg, a finding that indicates that Vo(2) under this circumstance is independent of oxygen supply and is discordant with the conventional hypothesis of metabolic regulation of the oxygen supply to tissue.