Brain energy metabolism measured by (13)C magnetic resonance spectroscopy in vivo upon infusion of [3-(13)C]lactate

Research output: Contribution to journalArticle

Abstract

The brain uses lactate produced by glycolysis as an energy source. How lactate originated from the blood stream is used to fuel brain metabolism is not clear. The current study measures brain metabolic fluxes and estimates the amount of pyruvate that becomes labeled in glial and neuronal compartments upon infusion of [3-(13)C]lactate. For that, labeling incorporation into carbons of glutamate and glutamine was measured by (13)C magnetic resonance spectroscopy at 14.1 T and analyzed with a two-compartment model of brain metabolism to estimate rates of mitochondrial oxidation, glial pyruvate carboxylation, and the glutamate-glutamine cycle as well as pyruvate fractional enrichments. Extracerebral lactate at supraphysiological levels contributes at least two-fold more to replenish the neuronal than the glial pyruvate pools. The rates of mitochondrial oxidation in neurons and glia, pyruvate carboxylase, and glutamate-glutamine cycles were similar to those estimated by administration of (13)C-enriched glucose, the main fuel of brain energy metabolism. These results are in agreement with primary utilization of exogenous lactate in neurons rather than astrocytes.

Details

Authors
External organisations
  • Swiss Federal Institute of Technology
Research areas and keywords

Keywords

  • Animals, Blood Gas Analysis, Brain, Carbon Isotopes, Energy Metabolism, Glutamic Acid, Glutamine, Hydrogen-Ion Concentration, Lactic Acid, Magnetic Resonance Spectroscopy, Male, Radionuclide Imaging, Rats, Rats, Sprague-Dawley, Journal Article, Research Support, Non-U.S. Gov't
Original languageEnglish
Pages (from-to)1009-18
Number of pages10
JournalJournal of Neuroscience Research
Volume93
Issue number7
Publication statusPublished - 2015 Jul
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes