Figure 9.

Glucose (Glc) from the vasculature is metabolized to lactate (Lac) in astrocytes, exported into the extracellular fluid, taken up by neurons and processed [via pyruvate (Pyr) and acetate (Ac)] by the TCA cycle. This spins off glutamate (Glt), which is released and then taken up by astrocytes, which convert it to glutamine (Gln), which is released into the extracellular fluid and taken up by neurons, which re-convert it to glutamate. For details of the relevant membrane transporters (see Chih and Roberts, 2003; Gallagher et al., 2009; Pellerin and Magistretti, 2012). Besides Lac production in situ from Glc, Lac may also be taken up from the circulation, (see Ide et al., 2000; Overgaard et al., 2012; Jalloh et al., 2013). For typical concentrations of the above species and PbtO₂ (see Gallagher et al., 2009; Timofeev et al., 2011a,b). Originally published by Gallagher et al. (2009) in Brain 132: 2839–2849, and reproduced with permission of Oxford Journals.