Age-dependent changes in the hippocampal antioxidant ability of EL mice.

Electron spin resonance (ESR) spectroscopy combined with in vivo microdialysis was used to analyze the antioxidant ability in the hippocampus of mice in an interictal state of EL mice utilizing decay ratio of an exogenously applied nitroxide radical (3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (PCAM)). In EL mice with a history of frequent seizures, the half-life of the electron paramagnetism of PCAM in the hippocampus was prolonged. These results revealed decreased antioxidant ability, suggesting vulnerability against oxidative stress. Our data suggest that epileptogenesis in EL mice with chronic seizures is associated with functional failure due to the oxidized redox state and revealed that the decreased hippocampal antioxidant ability is related to the regional vulnerability to oxidative stress in the limbic system of EL mice during epileptogenesis.