For each of isoflurane-anesthetized rats, the concentration of glutamate ([glu]) was plotted against the concentration of glucose ([glc]). Statistical analysis revealed that for the hippocampus, the Pearson's correlation between [glu] and [glc] was positively correlated (r=0.742) with a P-value of 0.035. In contrast, for the parietal cortex, [glu] and [glc] were negatively correlated (r=−0.769, P=0.026).