Development and persistence of kindled seizures after repeated injections of pentylenetetrazol in rats and guinea pigs.

Pentylenetetrazol (PTZ) was injected into rats (30 or 35 mg/kg) and guinea pigs (40 or 45 mg/kg) daily or every second day. A progressive development of seizure activity after this treatment was observed. Doses ineffective after the first injection induced tonic seizures after 20 injections. Both kinds of treated animals immediately developed tonic seizures when PTZ was injected after a few months interruption for one time only. The results support the assumption that seizures induced by chronic injection of PTZ are similar to kindled seizures evoked by daily electrical stimulation and can be regarded as a model of epileptogenesis.