Localized in vivo H-1 NMR detection of neurotransmitter labeling in rat brain during infusion of [1-C-13] D-glucose

Resolved localized nuclear magnetic resonance (NMR) signals of H-1 bound to C-13 label in the carbon positions of glutamate C4, C3 and glutamine C4, C 3, as well as in aspartate C3, lactate C3, alanine C3, gamma-aminobutyric a cid C3, and glucose C1 were simultaneously observed in spectra obtained fro m rat brain in vivo. Time-resolved label incorporation was measured with a new adiabatic carbon editing and decoupling (ACED) single-voxel stimulated echo acquistion mode (STEAM) sequence. Adiabatic carbon broadband decouplin g of 12 kHz bandwidth was achieved in vivo, which decoupled the entire C-13 spectrum at 9.4 T Resonances from N-acetyl-aspartate and creatine were als o detected, consistent with natural-abundance C-13 levels. These results em phasize the potential of H-1 NMR for following complex biochemical pathways in localized areas of resting rat brain as well as during focal activation using infusions of C-13-labeled glucose. (C) 1999 Wiley-Liss, Inc.