Brain Oxygen Balance Under Various Experimental Pathophysiologycal Conditions
Normally, brain tissue copes with negative oxygen balance by increasing cerebral blood flow (CBF). We examined the effects of increasing oxygen demand, by inducing spreading depression (SD) under various oxygen balance states, on brain O2 balance. The Tissue Vitality Monitoring System was used, which enables real time simultaneous in vivomonitoring of CBF, mitochondrial NADH and tissue HbO2 from the same region of the cerebral cortex. SD was induced during normoxia, hypoxia, hyperoxia, ischemia, and in normal and ischemic brain after systemic epinephrine dministration. Under normoxia, hyperoxia and ischemia & epinephrine, the compensation of energy demand induced by SD, was carried out by increasing CBF. The higher oxygen delivery under hyperoxia and epinephrine did not change the pattern of recovery from SD as compared to normoxia, whereas in the ischemic and hypoxic brain, the recovery from SD was prolonged, indicating a lake in oxygen delivery. Epinephrine infusion in the ischemic rat, decreased oxyhemoglobin utilization during SD, indicating that tissue oxygen balance improves even under higher oxygen demand induced by SD.
KeywordsCerebral Blood Flow Ischemic Brain Cortical Spreading Depression Spreading Depression Oxygen Balance
Unable to display preview. Download preview PDF.
- 7.A. Mayevsky and G. Rogatsky, Mitochondrial function in vivoevaluated by NADH fluorescence: From animal models to human studies, Am. J. Physiol Cell Physiol. ., (2007)Google Scholar
- 9.T. Back, K. Kohno, and K. A. Hossmann, Cortical negative DC deflections following middle cerebral artery occlusion and KCl-induced spreading depression: Effect on blood flow, tissue oxygenation and electroencephalogram, J. CBF Metab. 14, 12-19 (1994)Google Scholar
- 10.A. Mayevsky and H. R. Weiss, Cerebral blood flow and oxygen consumption in cortical spreading depression, J. CBF Metab. 11, 829-836 (1991)Google Scholar