Overshoot of oxygen pressure in post-hypoxic brain tissue: a re-evaluation

Tissue oxygen pressure (ptO2) was measured with noble metal microelectrodes in hippocampal slices in vitro. During hypoxia, the ptO2 at 100 micron depth fell rapidly to less than 20 mm Hg. During reoxygenation, large transient ptO2 increases above normoxic values were observed. These data demonstrate that ptO2 'overshoots' occur independently of in situ posthypoxic hyperemia and may reflect pathologic chemical reactions in brain tissue during reoxygenation.