Calcium channel blocker flunarizine suppresses epileptiform activity induced by penicillin in rats

Epilepsy is a neurological disorder that affects approximately 1% of the world population. It is accepted that calcium influx into the cell is the first step of epileptic neuronal events. In the present study, the effects of flunarizine on epileptiform activity were investigated in an experimental epilepsy model induced by intracortical (i.c.) penicillin administration. The left cerebral cortex was exposed by craniotomy in anaesthetised rats. The epileptic focus was produced by injection of penicillin G potassium (500 units) into the somatomotor cortex. After epileptiform activity reached maximum frequency and amplitude, flunarizine was injected into the same area with a Hamilton microinjector. Before flunarizine administration, the average frequency of spikes was 18.7 +/- 2.1 /min and the average amplitude of the spikes was 1123 +/- 85 muV. Microinjection of flunarizine (10, 100 muM) into the same area inhibited electrocorticogram epileptiform activity for 4-5 minutes (p <0.001). Solvent alone did not affect epileptiform activity (p <0.05). The results of this study suggest that flunarizine may be an anticonvulsant agent for the treatment of epilepsy.