TY - JOUR
T1 - Increased lactate/pyruvate ratio augments blood flow in physiologically activated human brain
AU - Mintun, Mark A.
AU - Vlassenko, Andrei G.
AU - Rundle, Melissa M.
AU - Raichle, Marcus E.
PY - 2004/1/13
Y1 - 2004/1/13
N2 - The factors regulating cerebral blood flow (CBF) changes in physiological activation remain the subject of great interest and debate. Recent experimental studies suggest that an increase in cytosolic NADH mediates increased blood flow in the working brain. Lactate injection should elevate NADH levels by increasing the lactate/ pyruvate ratio, which is in near equilibrium with the NADH/NAD+ ratio. We studied CBF responses to bolus lactate injection at rest and in visual stimulation by using positron-emission tomography in seven healthy volunteers. Bolus lactate injection augmented the CBF response to visual stimulation by 38-53% in regions of the visual cortex but had no effect on the resting CBF or the whole-brain CBF. These lactate-induced CBF increases correlated with elevations in plasma lactate/pyruvate ratios and in plasma lactate levels but not with plasma pyruvate levels. Our observations support the hypothesis that an increase in the NADH/NAD+ ratio activates signaling pathways to selectively increase CBF in the physiologically stimulated brain regions.
AB - The factors regulating cerebral blood flow (CBF) changes in physiological activation remain the subject of great interest and debate. Recent experimental studies suggest that an increase in cytosolic NADH mediates increased blood flow in the working brain. Lactate injection should elevate NADH levels by increasing the lactate/ pyruvate ratio, which is in near equilibrium with the NADH/NAD+ ratio. We studied CBF responses to bolus lactate injection at rest and in visual stimulation by using positron-emission tomography in seven healthy volunteers. Bolus lactate injection augmented the CBF response to visual stimulation by 38-53% in regions of the visual cortex but had no effect on the resting CBF or the whole-brain CBF. These lactate-induced CBF increases correlated with elevations in plasma lactate/pyruvate ratios and in plasma lactate levels but not with plasma pyruvate levels. Our observations support the hypothesis that an increase in the NADH/NAD+ ratio activates signaling pathways to selectively increase CBF in the physiologically stimulated brain regions.
UR - http://www.scopus.com/inward/record.url?scp=0346456853&partnerID=8YFLogxK
U2 - 10.1073/pnas.0307457100
DO - 10.1073/pnas.0307457100
M3 - Article
C2 - 14704276
AN - SCOPUS:0346456853
SN - 0027-8424
VL - 101
SP - 659
EP - 664
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 2
ER -