Alteration of brain glycogen turnover in the conscious rat after 5h of prolonged wakefulness

Article Article scientifique Article Alteration of brain glycogen turnover in the conscious rat after 5h of prolonged wakefulness eng 2009 author Morgenthaler Florence D author Lanz Bernard R author Petit Jean-Marie 134528 author Frenkel Hanne author Magistretti Pierre 133561 author Gruetter Rolf 636584 45-51 10.1016/j.neuint.2009.02.023 19428806 0197-0186 Although glycogen (Glyc) is the main carbohydrate storage component, the role of Glyc in the brain during prolonged wakefulness is not clear. The aim of this study was to determine brain Glyc concentration ([]) and turnover time (tau) in euglycemic conscious and undisturbed rats, compared to rats maintained awake for 5h. To measure the metabolism of [1-(13)C]-labeled Glc into Glyc, 23 rats received a [1-(13)C]-labeled Glc solution as drink (10% weight per volume in tap water) ad libitum as their sole source of exogenous carbon for a "labeling period" of either 5h (n=13), 24h (n=5) or 48 h (n=5). Six of the rats labeled for 5h were continuously maintained awake by acoustic, tactile and olfactory stimuli during the labeling period, which resulted in slightly elevated corticosterone levels. Brain [Glyc] measured biochemically after focused microwave fixation in the rats maintained awake (3.9+/-0.2 micromol/g, n=6) was not significantly different from that of the control group (4.0+/-0.1 micromol/g, n=7; t-test, P>0.5). To account for potential variations in plasma Glc isotopic enrichment (IE), Glyc IE was normalized by N-acetyl-aspartate (NAA) IE. A simple mathematical model was developed to derive brain Glyc turnover time as 5.3h with a fit error of 3.2h and NAA turnover time as 15.6h with a fit error of 6.5h, in the control rats. A faster tau(Glyc) (2.9h with a fit error of 1.2h) was estimated in the rats maintained awake for 5h. In conclusion, 5h of prolonged wakefulness mainly activates glycogen metabolism, but has minimal effect on brain [Glyc]. Algorithms Animals Aspartic Acid/analogs & derivatives/metabolism Blood Glucose/metabolism Brain Chemistry/physiology Consciousness/physiology Corticosterone/blood/metabolism Glucose/metabolism Glycogen/metabolism Magnetic Resonance Spectroscopy Rats Rats, Sprague-Dawley Wakefulness/physiology Dewey 616.0757 62 Département de radiologie et informatique médicale 227 false 523 CIBM 863 Neurochemistry international 55 1-3 8c6c5406-c337-4139-8dc3-7b4288a33298 Article (Published version) Public 1-s2.0-S0197018609000965-main.pdf 256704 application/pdf openAccess Faculté de médecine / Section de médecine clinique / Département de radiologie et informatique médicale

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Alteration of brain glycogen turnover in the conscious rat after 5h of prolonged wakefulness	Neurochemistry international			2009	639	573

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Petit, Jean-Marie