Figure 4.

Experimental results of V_cycle and the rates of glucose oxidation measured simultaneously in each rat going from N₂O/morphine to α-chloralose to pentobarbital (least active), at graded anesthesia. The best fit line gives CMRglc(ox) = 1.04 V_cycle + 0.10. The slope shows that each mole of neurotransmitter glutamate cycling requires the oxidation of one mole of glucose. The awake, resting state has CMRglc(ox) ≈0.8 μmol/min/g, which means that under this condition ≈85% of the brain energy consumption is dedicated to V_cycle (9).