Repeated or prolonged isoflurane exposure reduces mitochondrial oxidizing effects.

VOLATILE anesthetics are well known to have cardioprotective effects similar to those of ischemic preconditioning, but the mechanisms remain unclear. Recent evidence indicates that the protective effects of KATP channel openers may be due to action on mitochondrial KATP channels. 12–16 We have previously reported that 15 min of volatile anesthetic exposure induces mitochondrial flavoprotein oxidation via mitochondrial KATP channel activation, which may contribute to anesthetic-induced preconditioning. Volatile anesthetic exposure produces a memory period after exposure during which damage from ischemia is diminished, even though the anesthetic is no longer being administered. We designed the present study to examine time factors that may influence mitochondrial oxidation in anesthetic-induced preconditioning using mitochondrial flavoprotein fluorescence (MFF) as an endogenous reporter of mitochondrial redox state.