The detection of cytochrome oxidase heme iron and copper absorption in the blood-perfused and blood-free brain in normoxia and hypoxia.
The detection of cytochrome oxidase heme iron and copper absorption in the blood-perfused and blood-free brain in normoxia and hypoxia.
复制标题
常氧和缺氧条件下有血脑和无血脑中细胞色素氧化酶血红素铁和铜吸收的检测。
DOI：
10.1016/0003-2697(91)90200-d
复制
发表时间：
1991
影响因子：
2.9
通讯作者：
Chance,B
中科院分区：
文献类型：
--
作者：
Miyake,H;Nioka,S;Zaman,A;Smith,DS;Chance,B
细胞色素和血红蛋白的变化，在体内大鼠和猫的大脑的分辨率需要在宽波长范围（580-1100 nm）的研究与新的光谱技术，使用无血和血液灌注的大脑。组织氧从生理水平变化到0，血细胞比容从正常变化到小于1%。实验结果进行了多组分分析，使用比尔-朗伯定律。在正常血细胞比容下，发现大鼠和猫脑中血红蛋白的氧饱和度为30-50%，表明光学方法主要对毛细血管床静脉末端的饱和度作出反应。在低血细胞比容的情况下，两个大脑都显示出还原细胞色素c的吸收带，细胞色素aa 3的铁成分，加上氧化铜成分的吸收带。在猫的大脑中，背景吸收在所有波长上都发生了变化。因此，在光谱中没有观察到等吸光点。然而，在老鼠的大脑中，它们很容易被观察到。在猫脑的不同光谱中，近红外区的水吸收的“泛音”被发现是显著的，但在大鼠脑中不是。在大鼠和猫的大脑中，在常氧-缺氧过渡期间，细胞色素aa 3的血红素和铜组分的吸光度发生了平行的变化。在两个大脑中，605 nm处的铁吸光度与830 nm处的铜吸光度之比远小于体外值，这是由于在较短波长处光子迁移的路径长度较短。结果表明，在无血脑细胞色素测量的有效性，但确认在血液灌注脑细胞色素铁和铜的定量测量的极端困难。
The resolution of cytochrome and hemoglobin changes in in vivo rat and cat brains has required studies over wide wavelength ranges (580–1100 nm) with a novel spectroscopic technique using blood-free and blood-perfused brains. Tissue oxygen was varied from physiological levels to 0 and hematocrits were varied from normal to less than 1%. The experimental results were subjected to a multicomponent analysis using the Beer-Lambert law. At normal hematocrits, the oxygen saturation of hemoglobin in the brain was found to be 30–50% in rats and cats, indicating that the optical method responded primarily to the saturation of the venous ends of the capillary beds. With low hematocrits, both brains showed the absorption band of reduced cytochrome c, the iron component of cytochrome aa3, plus the absorption band of the oxidized copper component. In cat brains, the background absorption changed at all wavelengths. Thus, no isosbestic points were observed in the spectra. In rat brains, however, they were readily observed. The “overtones” of water absorption in the NIR region were found to be significant in the difference spectra of the cat brain, but not in the rat brain. Parallel absorbance changes in the heme and copper components of cytochrome aa3were obtained in rat and cat brains during the normoxic-hypoxic transition. The ratio of the iron absorbance at 605 nm to the copper absorbance at 830 nm is much smaller in both brains than the in vitro value due to the shorter path length of photon migration at the shorter wavelengths. The results indicate the validity of cytochrome measurements in the blood-free brain but confirm the extreme difficulty of quantitative measurements of cytochrome iron and copper in the blood-perfused brain.