Effect of 60-min sevoflurane preconditioning on sodium and potassium concentrations during hypoxia. Sodium (Na+) and potassium (K+) concentrations were measured in the cornus ammonis 1 (CA1) region of rat hippocampal slices at 5 (A) and 10 (B) min of hypoxia. The tissue was treated with 4% sevoflurane in 95% O2–5% CO2 for 60 min and then the anesthetic was washed out with 95% O2–5% CO2 for 5 min (Sevo or Sevo/Hypo). The tissue was then subjected to either 5 min (A) or 10 min (B) of hypoxia by aerating the tissue with 95% N2–5% CO2; the Normoxia and Sevo groups were not subjected to hypoxia. At the end of the experiment, the tissue from each group was placed in ice-cold isotonic sucrose for 10 min to wash out the extracellular ions. The CA1 regions were then dissected, dried, weighed, and analyzed in a flame photometer. Values are the mean ± SD (n = 8 animals per group) and are expressed as nmol per mg dry weight. The normoxia groups (Normoxia and Sevo) are significantly different from the hypoxia groups (Hypoxia and Sevo/Hypo); P < 0.05 (Newman–Keuls multiple comparison test; n = 8/group); however, the Hypoxia and Sevo/Hypo groups are not significantly different from each other (Newman–Keuls or paired t test).
