Effects of injection interval on pentylenetetrazol (PTZ) kindled seizures in rats

We investigated the effects of different injection intervals, (24 hr, 48 hr, and 72 hr) on the development of kindled seizures induced by repetitive pentylenetetrazol (PTZ) injections (30 mg/kg) in rats. Regardless of injection interval, kindled seizures were obtained 1 week after the completion of consecutive PTZ injections. This PTZ kindled seizure model appears to mimick generalized seizure and be useful in the investigation of seizure phenomenon. With 48 and 72 hr injection interval, the seizure responses gradually increased with consecutive injections. The convulsive severity of 24 hr interval group showed a transient increased and then stabilized at a low score (2/6). This difference between these injection interval might reflect the appearance of some short of inhibition during the more closely spaced (24 hr) repeated injections.