Article: article from journal or magazin.
Review (review): journal as complete as possible of one specific subject, written based on exhaustive analyses from published work.
Imagerie fonctionnelle cérébrale: rôle du couplage métabolique entre astrocytes et neurones [Functional brain imaging: role metabolic coupling between astrocytes and neurons]
Revue Médicale de la Suisse romande
Publication types: English Abstract ; Journal Article ; Review
Despite the technological sophistication of brain imaging techniques, the precise mechanisms and cell types involved in coupling and in generating metabolic signals are still debated. Recent experimental data on the cellular and molecular mechanisms that underlie the fluorodeoxyglucose (FDG)--based PET imaging point to a critical role of a particular brain cell type, the astrocytes, in coupling neuronal activity to glucose utilization. Indeed, astrocytes possess receptors and re-uptake sites for a variety of neurotransmitters, including glutamate, the predominant excitatory neurotransmitter in the brain. In addition, astrocytic end-feet, which surround capillaries, are enriched in the specific glucose transporter GLUT-1. These features allow astrocytes to "sense" synaptic activity and to couple it with energy metabolism. In vivo and in vitro data support the following functional model: in response to glutamate released by active neurons, glucose is predominantly taken up by astrocytic end-feet; glucose is then metabolized to lactate which provides a preferred energy substrate for neurons. These data support the notion that astrocytes markedly contribute to the FDG-PET signal.
Astrocytes, Citric Acid Cycle, Energy Metabolism, Enzyme Activation, Glucose, Glutamates, Humans, Neurons, Sodium-Potassium-Exchanging ATPase, Tomography, Emission-Computed
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