SUPEROXIDE PRODUCTION IN EXPERIMENTAL SEIZURES IN CATS

Background and Purpose: Seizures cause cerebrovascular responses similar to those seen in conditions such as acute hypertension, ischemia/reperfusion, or fluid-percussion brain injury, which are associated with the generation of superoxide. Accordingly, we studied production of superoxide in experimental seizures. Methods: Superoxide production was measured in anesthetized cats equipped with double cranial windows using the superoxide dismutase-inhibitable reduction of nitro blue tetrazolium as a measure of superoxide production. Seizures were induced by intravenous bicuculline. The contribution of hypertension associated with seizures was studied by maintaining arterial blood pressure constant by bleeding. Results. Significant superoxide dismutase-inhibitable reduction of nitro blue tetrazolium indicative of superoxide production was found during seizures with or without control of arterial blood pressure (1.10+/-0.27 and 1.29+/-0.16 nmol/l/min, respectively). Conclusions: The results show that experimental seizures are associated with superoxide generation that is independent of the rise in arterial blood pressure. It is likely that superoxide generation is due to the metabolic changes that occur during seizures.