Figure 4.

Model of non‐glycolytic metabolism interaction in astroglial and neuronal cells. In the presence of glucose, free fatty acids in the brain are taken up and oxidised by astroglial and neuronal cells to produce ATP via Krebs cycle/OxPhos as a supplementary energy source. Potentially, MCFA are mainly oxidised in neurons and other fatty acids in astroglial cells (dark green pathways). Under glucose deprivation: (1) astroglial cells can conduct ketogenesis to provide fast energetic substrates to neurons (light green pathway) and (2) ketone bodies from the bloodstream are taken up and oxidised by brain cells, providing up to ~70% of the energetic requirements (blue pathways). (3) Glutamate/glutamine is necessary to regulate the Krebs cycle, playing a major role in the communication of astroglia and neurons by processing excessive synaptic glutamate and providing amino acid glutamine. Also, but to a lesser extent, astroglial produced alpha‐ketoglutarate can be converted into glutamate to promote neurotransmitter and/or neuronal energetic by‐product release (mustard coloured pathways). (5). Neurotransmitter GABA can also be converted into a Krebs cycle metabolite depending on the needs of the mitochondrial Krebs cycle (red coloured pathway).