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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 …