Region-specific induction of hypoxic tolerance by expression of stress proteins and antioxidant enzymes

We examined the induction of hypoxic tolerance after hypoxic preconditioning in the frontal cortex, caudate putamen and thalamus using the dynamic positron autoradiography technique and [18F]2-fluoro-2-deoxy-D-glucose with rat brain slices. Hypoxic tolerance induction was confirmed in the frontal cortex, but not in the caudate putamen and thalamus. Next, we compared the gene expression in the frontal cortex and caudate putamen using the ATLAS Rat Stress Array, and found that the expression of 150-kDa oxygen-regulated protein and mitochondrial heat shock protein 70 as stress proteins, and copper-zinc-containing superoxide dismutase and manganese-containing superoxide dismutase as antioxidant enzymes was elevated only in the frontal cortex. These results suggest that the induction of hypoxic tolerance after hypoxic preconditioning is region-specific, and stress proteins and antioxidant enzymes participate in this phenomenon.