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Abstract #0215

CO2 Breathing Suppresses Cerebral Metabolic Rate of Oxygen

Feng Xu1, Uma Yezhuvath1, Matthew R. Brier2, John Hart, Jr. 3, Michael A. Kraut4, Clair Moore2, Hanzhang Lu1

1University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA; 2University of Texas at Dallas, Dallas, TX, USA; 3University of Texas at Dallas, Dallas, TX, USA; 4Johns Hopkins University, Baltimore, MD, USA

CO2 is highly potent in modulating cerebral blood flow. However the effect of CO2 on neuronal activity and brain energy consumption is not yet known. Here we used a novel technique to measure global cerebral metabolic rate of oxygen, CMRO2, during normocapnia and hypercapnia, and showed that 5% CO2 breathing can reduce the CMRO2 by 135% (n=8, p<0.001). We further used electroencephalography (EEG) to investigate which component of the neurons energy budget has changed, and found that the delta band in the EEG signal was enhanced by 18%, suggesting that brain was switched to a low-arousal state during CO2 breathing.