Stimulation-induced increases of astrocytic oxidative metabolism in rats and humans investigated with 1-11C-acetate

J Cereb Blood Flow Metab. 2009 Jan;29(1):44-56. doi: 10.1038/jcbfm.2008.86. Epub 2008 Aug 20.


The purpose of this study was to investigate astrocytic oxidative metabolism using 1-(11)C-acetate. 1-(11)C-acetate kinetics were evaluated in the rat somatosensory cortex using a beta-scintillator during different manipulations (test-retest, infraorbital nerve stimulation, and administration of acetazolamide or dichloroacetate). In humans a visual activation paradigm was used and kinetics were measured with positron emission tomography. Data were analyzed using a one-tissue compartment model. The following features supported the hypothesis that washout of radiolabel (k(2)) is because of (11)C-CO(2) and therefore related to oxygen consumption (CMRO(2)): (1) the onset of (11)C washout was delayed; (2)k(2) was not affected by acetazolamide-induced blood flow increase; (3)k(2) demonstrated a significant increase during stimulation in rats (from 0.014+/-0.007 to 0.027+/-0.006 per minute) and humans (from 0.016+/-0.010 to 0.026+/-0.006 per minute); and (4) dichloroacetate led to a substantial decrease of k(2). In the test-retest experiments K(1) and k(2) were very stable. In summary, 1-(11)C-acetate seems a promising tracer to investigate astrocytic oxidative metabolism in vivo. If the washout rate indeed represents the production of (11)C-CO(2), then its increase during stimulation would point to a substantially higher astrocytic oxidative metabolism during brain activation. However, the quantitative relationship between k(2) and CMRO(2) needs to be determined in future experiments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / pharmacology*
  • Acetazolamide / pharmacology
  • Adult
  • Animals
  • Astrocytes / drug effects*
  • Astrocytes / metabolism*
  • Carbon Radioisotopes
  • Humans
  • Male
  • Oxygen Consumption / drug effects*
  • Positron-Emission Tomography
  • Rats
  • Reproducibility of Results


  • Acetates
  • Carbon Radioisotopes
  • Acetazolamide