Midazolam suppresses spike-and-wave rhythm accompanying three different models of epileptic seizures.

The action of a water-soluble benzodiazepine midazolam (0.1 and 1 mg/kg i.p.) was tested against three models of spike-and-wave rhythm in rats: rhythmic metrazol activity (a model of human absence seizures), minimal metrazol seizures, and epileptic afterdischarges induced by low-frequency cortical stimulation (probably models of human myoclonic seizures). Midazolam was able to reduce spike-and-wave activity in all three models, but there were quantitative differences: the lower dose was effective only against rhythmic metrazol activity, but its action against two other models was negligible, whereas the higher dose of midazolam resulted in significant effects in all three models. These quantitative differences are not sufficient to prove our hypothesis that the spike-and-wave rhythm represents different phenomena in various models. A spread of epileptic activity into brain structures other than the thalamocortical system determines the type of epileptic seizures.