*2.7. Brain Hexokinase (HK) Activity*

Fresh brains were homogenized in medium containing 200 mM mannitol, 76 mM sucrose, 1 mM EGTA, 0.1 mM PMSF and 10 mM TRIS (pH 7.4). The homogenate was centrifuged at 650*g* for 8 min. The activity of the hexokinase (HK) in the cytosol was measured using the liquid fraction obtained by an additional centrifugation of the brain homogenate supernatant (40 min at 29,000*g*) [50]. This procedure precipitates the mitochondria and other cell components. The incubation medium contained in a final volume of 1 mL: 100 mM Tris-HCl (pH 7.2), 20 mM glucose, 2 mM ATP, 10 mM MgCl2, 1.5 mM NAD<sup>+</sup>, 5 units of glucose 6-phosphate dehydrogenase from *Leuconostoc mesenteroides* and 50 μL of high speed centrifugation supernatant. The reaction was monitored spectrophotometrically at 340 nm (ε = 6.22 × 10<sup>3</sup> M−<sup>1</sup> cm<sup>−</sup>1).
