FIGURE 3.

Flux of energetic metabolites in the central nervous system (CNS). Glucose, lactate, ketone bodies, and fatty acids pass into the CNS via endothelial cells and are then transferred to astrocytes, oligodendrocytes, and neurons. Glucose trafficking is mediated by glucose transporter (GLUT) 1 (blue channels) in endothelial cells, astrocytes, and oligodendrocytes and by GLUT3 (red channels) in neurons. Lactate and ketone bodies pass through MCT1 in endothelial cells, astrocytes, and oligodendrocytes (orange channels) and MCT4 in neurons. Fatty acids can diffuse directly through plasma membranes. Metabolites can be shared between astrocytes and oligodendrocytes through gap junctions formed by connexins (purple). Glucose can be converted and stored in astrocytes as glycogen. Glucose and lactate can be converted into pyruvate by glycolysis to yield ATP. Pyruvate, ketone bodies, and fatty acids can be converted into acetyl‐CoA (Ac‐CoA) and used to produce considerable amounts of ATP by oxidative phosphorylation in mitochondria via the TCA cycle and the electron transport chain (ETC). This source of ATP is particularly important for neurons because of their higher energetic demands. Fatty acids are mainly used by oligodendrocytes to produce myelin, as is a substantial portion of the acetyl‐CoA produced from other metabolites. Created with BioRender.