Hoshi Y, Kobayashi N, Tamura M
Biophysics Group, Research Institute for Electronic Science, Hokkaido University, Sapporo 060 - 0812, Japan.
J Appl Physiol (1985). 2001 May;90(5):1657-62. doi: 10.1152/jappl.2001.90.5.1657.
Using a newly developed perfused rat brain model, we examined direct effects of each change in cerebral blood flow (CBF) and oxygen metabolic rate on cerebral hemoglobin oxygenation to interpret near-infrared spectroscopy signals. Changes in CBF and total hemoglobin (tHb) were in parallel, although tHb showed no change when changes in CBF were small (< or =10%). Increasing CBF caused an increase in oxygenated hemoglobin (HbO(2)) and a decrease in deoxygenated hemoglobin (deoxy-Hb). Decreasing CBF was accompanied by a decrease in HbO(2), whereas changes in direction of deoxy-Hb were various. Cerebral blood congestion caused increases in HbO(2), deoxy-Hb, and tHb. Administration of pentylenetetrazole without increasing the flow rate caused increases in HbO(2) and tHb with a decrease in deoxy-Hb. There were no significant differences in venous oxygen saturation before vs. during seizure. These results suggest that, in activation studies with near-infrared spectroscopy, HbO(2) is the most sensitive indicator of changes in CBF, and the direction of changes in deoxy-Hb is determined by the degree of changes in venous blood oxygenation and volume.
利用新开发的灌注大鼠脑模型，我们研究了脑血流量（CBF）和氧代谢率的每一项变化对脑血红蛋白氧合的直接影响，以解读近红外光谱信号。CBF和总血红蛋白（tHb）的变化是平行的，尽管当CBF变化较小时（≤10%），tHb没有变化。CBF增加导致氧合血红蛋白（HbO₂）增加，脱氧血红蛋白（deoxy-Hb）减少。CBF降低伴随着HbO₂减少，而deoxy-Hb的变化方向则各不相同。脑充血导致HbO₂、deoxy-Hb和tHb增加。在不增加流速的情况下给予戊四氮导致HbO₂和tHb增加，deoxy-Hb减少。癫痫发作前和发作期间静脉血氧饱和度没有显著差异。这些结果表明，在近红外光谱激活研究中，HbO₂是CBF变化最敏感的指标，deoxy-Hb的变化方向由静脉血氧合和血容量的变化程度决定。
