Energy homeostasis in the brain is maintained by oxidative metabolism of glucose, primarily to fulfil the energy demand associated with ionic movements in neurons and astrocytes. In this contribution we review the experimental evidence that grounds a specific role of glycogen metabolism in supporting the functional energetic needs of astrocytes during the removal of extracellular potassium. Based on theoretical considerations, we further discuss the hypothesis that the mobilization of glycogen in astrocytes serves the purpose to enhance the availability of glucose for neuronal glycolytic and oxidative metabolism at the onset of stimulation. Finally, we provide an evolutionary perspective for explaining the selection of glycogen as carbohydrate reserve in the energy-sensing machinery of cell metabolism.
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Acknowledgments We thank two anonymous referees for valuable comments and constructive suggestions to the manuscript. The author S. Mangia thanks the funding supports: Minnesota Medical Foundation, NIH grants BTRR-P41RR008079, P30 NS057091, NIH R01 DK62440. This publication was also supported by the NIH grant 1UL1RR033183 from the National Center for Research Resources (NCRR) to the University of Minnesota Clinical and Translational Science Institute (CTSI). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the CTSI or the NIH.
- Brain glycogen
- Neurometabolic coupling