Increased lactate/pyruvate ratio augments blood flow in physiologically activated human brain

• DOI: 10.1073/pnas.0307457100
• Publication Date: 2004-01-13T18:28:06Z
• Authors: Mark A. Mintun; Andrei G. Vlassenko; Melissa M. Rundle; Marcus E. Raichle
• Keywords: Adult; Male; Magnetic Resonance Imaging; 03 medical and health sciences; 0302 clinical medicine; Cerebrovascular Circulation; Pyruvic Acid; Humans; Female; Lactic Acid; Photic Stimulation; Tomography, Emission-Computed

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 cytosolic NADH mediates increased working brain. Lactate injection should elevate levels by increasing lactate/pyruvate ratio, which is near equilibrium with NADH/NAD + ratio. We studied CBF responses to bolus lactate at rest visual stimulation using positron-emission tomography seven healthy volunteers. Bolus augmented response 38–53% regions cortex but had no effect on resting or whole-brain CBF. These lactate-induced increases correlated elevations plasma ratios not pyruvate levels. Our observations support hypothesis ratio activates signaling pathways selectively physiologically stimulated brain regions.