Influence of clonazepam on cortical epileptogenic foci in the rat

The antiepileptic action of clonazepam was studied on epileptogenic foci induced by penicillin in sensorimotor cortex in acute experiments in rats. Clonazepam (1 mg/kg intraperitoneally) only moderately decreased the frequency of interictal discharges of single cortical focus and delayed the propagation of discharges into the ipsilateral occipital region. On the contrary, clonazepam failed to influence the callosal projection of interictal discharges in single unilateral as well as in two symmetrical foci. Spontaneous transition of interictal discharges into ictal phases regularly seen when two symmetrical foci were formed was only delayed but not blocked by clonazepam. It may be concluded that clonazepam exhibits only a weak anticonvulsant action against cortical foci and against secondary generalization of epileptic activity.