Excitatory/inhibitory neuronal metabolic balance in mouse hippocampus upon infusion of [U-13C6]glucose. Issue 2 (February 2021)

• Record Type: Journal Article
• Authors: Cherix, Antoine; Donati, Guillaume; Lizarbe, Blanca; Lanz, Bernard; Poitry-Yamate, Carole; Lei, Hongxia; Gruetter, Rolf
• Is Part Of: Journal of cerebral blood flow & metabolism. Volume 41:Issue 2(2021)
• Page Start: 282
• Page End: 297
• Publication Date: 2021-02
• Subjects: 1H-[13C]-MRS -- neuronal metabolism -- metabolic modeling -- TCA cycle -- mouse hippocampus; Cerebral circulation -- Periodicals; Brain -- Metabolism -- Periodicals; Brain -- Blood-vessels -- Periodicals; Cerebrovascular disease -- Periodicals; 612.824
• DOI: 10.1177/0271678X20910535
• Languages: English
• ISSNs: 0271-678X

Abstract

Hippocampus plays a critical role in linking brain energetics and behavior typically associated to stress exposure. In this study, we aimed to simultaneously assess excitatory and inhibitory neuronal metabolism in mouse hippocampus in vivo by applying 18 FDG-PET and indirect 13 C magnetic resonance spectroscopy ( 1 H-[ 13 C]-MRS) at 14.1 T upon infusion of uniformly 13 C-labeled glucose ([U- 13 C6 ]Glc). Improving the spectral fitting by taking into account variable decoupling efficiencies of [U- 13 C6 ]Glc and refining the compartmentalized model by including two γ-aminobutyric acid (GABA) pools permit us to evaluate the relative contributions of glutamatergic and GABAergic metabolism to total hippocampal neuroenergetics. We report that GABAergic activity accounts for ∼13% of total neurotransmission (VNT ) and ∼27% of total neuronal TCA cycle (VTCA ) in mouse hippocampus suggesting a higher VTCA /VNT ratio for inhibitory neurons compared to excitatory neurons. Finally, our results provide new strategies and tools for bringing forward the developments and applications of 13 C-MRS in specific brain regions of small animals.