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Title

Brain energy metabolism and neurotransmission at near-freezing temperatures: in vivo (1)H MRS study of a hibernating mammal

Authors
Henry, Pierre-Gilles
Russeth, Kevin P
Tkac, Ivan
Drewes, Lester R
Andrews, Matthew T
Published in Journal of Neurochemistry. 2007, vol. 101, no. 6, p. 1505-15
Abstract The brain of a hibernating mammal withstands physiological extremes that would result in cerebral damage and death in a non-hibernating species such as humans. To examine the possibility that this neuroprotection results from alterations in cerebral metabolism, we used in vivo(1)H NMR spectroscopy at high field (9.4 T) to measure the concentration of 18 metabolites (neurochemical profile) in the brain of 13-lined ground squirrels (Spermophilus tridecemlineatus) before, during, and after hibernation. Resolved in vivo(1)H NMR spectra were obtained even at low temperature in torpid hibernators ( approximately 7 degrees C). The phosphocreatine-to-creatine ratio was increased during torpor (+143%) indicating energy storage, and remained increased to a lesser extent during interbout arousal (IBA) (+83%). The total gamma-aminobutyric acid concentration was increased during torpor (+135%) and quickly returned to baseline during IBA. Glutamine (Gln) was decreased (-54%) during torpor but quickly returned to normal levels during IBA and after terminal arousal in the spring. Glutamate (Glu) was also decreased during torpor (-17%), but remained decreased during IBA (-20% compared with fall), and returned to normal level in the spring. Our observation that Glu and Gln levels are depressed in the brain of hibernators suggests that the balance between anaplerosis and loss of Glu and Gln (because of glutamatergic neurotransmission or other mechanisms) is altered in hibernation.
Keywords AnimalsAscorbic Acid/metabolismAspartic Acid/analogs & derivatives/metabolismBrain/metabolismBrain ChemistryCholine/metabolismCold TemperatureCreatine/metabolismEnergy Metabolism/physiologyEthanolamines/metabolismGlucose/metabolismGlutamic Acid/metabolismGlutamine/metabolismGlutathione/metabolismHibernation/physiologyInositol/metabolismLactic Acid/metabolismMagnetic Resonance SpectroscopyPhosphocreatine/metabolismSciuridae/physiologySynaptic Transmission/physiologyTaurine/metabolismGamma-Aminobutyric Acid/metabolism
Identifiers
PMID: 17437538
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Research group CIBM (863)
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HENRY, Pierre-Gilles et al. Brain energy metabolism and neurotransmission at near-freezing temperatures: in vivo (1)H MRS study of a hibernating mammal. In: Journal of Neurochemistry, 2007, vol. 101, n° 6, p. 1505-15. https://archive-ouverte.unige.ch/unige:32942

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Deposited on : 2014-01-08

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