Increased lactate/pyruvate ratio augments blood flow in physiologically activated human brain
AUTOR(ES)
Mintun, Mark A.
FONTE
National Academy of Sciences
RESUMO
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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=327204Documentos Relacionados
- Effect of decreased O2 supply to tissue on the lactate:pyruvate ratio in blood
- NADH augments blood flow in physiologically activated retina and visual cortex
- Performance during a strenuous swimming session is associated with high blood lactate: pyruvate ratio and hypoglycemia in fasted rats
- Effects of increased arterial pressure on blood flow in the damaged brain.
- A STUDY IN MAN OF CEREBRAL BLOOD FLOW AND CEREBRAL GLUCOSE, LACTATE AND PYRUVATE METABOLISM BEFORE AND AFTER EATING*