Regional glucose metabolism and glutamatergic neurotransmission in rat brain in vivo

RA De Graaf, GF Mason, AB Patel… - Proceedings of the …, 2004 - National Acad Sciences
Proceedings of the National Academy of Sciences, 2004National Acad Sciences
Multivolume 1H-[13C] NMR spectroscopy in combination with iv [1, 6-13C2] glucose infusion
was used to detect regional glucose metabolism and glutamatergic neurotransmission in the
halothane-anesthetized rat brain at 7 T. The regional information was decomposed into pure
cerebral gray matter, white matter, and subcortical structures by means of tissue
segmentation based on quantitative T1 relaxation mapping. The 13C turnover curves of [4-
13C] glutamate,[4-13C] glutamine, and [3-13C] glutamate+ glutamine were fitted with a two …
Multivolume 1H-[13C] NMR spectroscopy in combination with i.v. [1,6-13C2]glucose infusion was used to detect regional glucose metabolism and glutamatergic neurotransmission in the halothane-anesthetized rat brain at 7 T. The regional information was decomposed into pure cerebral gray matter, white matter, and subcortical structures by means of tissue segmentation based on quantitative T1 relaxation mapping. The 13C turnover curves of [4-13C]glutamate, [4-13C]glutamine, and [3-13C]glutamate + glutamine were fitted with a two-compartment neuronal-astroglial metabolic model. The neuronal tricarboxylic acid cycle fluxes in cerebral gray matter, white matter, and subcortex were 0.79 ± 0.15, 0.20 ± 0.11, and 0.42 ± 0.09 μmol/min per g, respectively. The glutamate-glutamine neurotransmitter cycle fluxes in cerebral gray matter, white matter, and subcortex were 0.31 ± 0.07, 0.02 ± 0.04, and 0.18 ± 0.12 μmol/min per g, respectively. The exchange rate between the mitochondrial and cytosolic metabolite pools was fast relative to the neuronal tricarboxylic acid cycle flux for all cerebral tissue types.
National Acad Sciences