Sodium signaling and astrocyte energy metabolism. Issue 10 (29th March 2016)

• Record Type: Journal Article
• Authors: Chatton, Jean‐Yves; Magistretti, Pierre J.; Barros, L. Felipe
• Is Part Of: Glia. Volume 64:Issue 10(2016:Oct.)
• Page Start: 1667
• Page End: 1676
• Publication Date: 2016-03-29
• Subjects: membrane transport -- Na, K‐ATPase -- neuron‐glia interactions -- glycolysis -- mitochondria -- syncytium -- lactate; Neuroglia -- Periodicals; Neurology -- Periodicals; 611.0188
• DOI: 10.1002/glia.22971
• Languages: English
• ISSNs: 0894-1491

Abstract

Abstract : The Na + gradient across the plasma membrane is constantly exploited by astrocytes as a secondary energy source to regulate the intracellular and extracellular milieu, and discard waste products. One of the most prominent roles of astrocytes in the brain is the Na + ‐dependent clearance of glutamate released by neurons during synaptic transmission. The intracellular Na + load collectively generated by these processes converges at the Na, K‐ATPase pump, responsible for Na + extrusion from the cell, which is achieved at the expense of cellular ATP. These processes represent pivotal mechanisms enabling astrocytes to increase the local availability of metabolic substrates in response to neuronal activity. This review presents basic principles linking the intracellular handling of Na + following activity‐related transmembrane fluxes in astrocytes and the energy metabolic pathways involved. We propose a role of Na + as an energy currency and as a mediator of metabolic signals in the context of neuron–glia interactions. We further discuss the possible impact of the astrocytic syncytium for the distribution and coordination of the metabolic response, and the compartmentation of these processes in cellular microdomains and subcellular organelles. Finally, we illustrate future avenues of investigation into signaling mechanisms aimed at bridging the gap between Na + and the metabolic machinery. GLIA 2016;64:1667–1676 Main points: Astrocytic sodium is an energy currency and a key mediator of neurometabolic coupling. Fluorescent probes for ions and metabolites are being combined to bridge the mechanistic gap between astrocytic sodium dynamics and the metabolic machinery.