Measurement of Carbohydrates and Their Derivatives in Neural Tissues

The mammalian brain has very small reserves of carbohydrates, which under normal circumstances are the preferred sources of energy in vivo. Thus, the cerebral cortex contains glucose at l–l.5 μmol/g fresh weight and a little more of the equivalent amount of glucose stored as glycogen (McIlwain and Bachelard, 1985). On death, very rapid rates of anaerobic metabolism continue postmortem, so within a few seconds, cerebral glucose in the mouse or rat brain falls to undetectable levels; glycogen is then mobilized, and the total stores of readily utilizable carbohydrate are severely depleted in less than 1 min. Concomitantly with these decreases, lactate increases to very high levels of some 3-to 4-fold normal within 1 min (Lowry et al., 1964). Other carbohydrates or their derivatives occur in minute amounts and do not contribute significantly to this process.