Effect of critical time window on development of

pentylenetetrazole Kindling is widely used as a model for epileptogenesis. The achievement of kindling criterion is known to require repeated drug injection during time to develop. In this article a series of experiments aimed to examin the hypothesis that after 4 primary injections only time is needed to induced kindling in wistar rats. Methods and Materials: In this experimental research, 32 male Wistar rats were divided in two groups. Control Group were kindled by repeated injections of pentylenetetrazole (PTZ; 37.5 mg/kg;i.p. 48 h interval), in case group were done 4 repeated injections of pentylenetetrazole and have 32 days time lapse, at the end of experiment two groups received same dose of PTZ simultaneously and seizure parameters were assessed. Data were analyzed using student’s t-test and one way ANOVA and Turkey’s test. Results showed there isn’t significant differences in seizure parameters such as seizure stage (control; 4.75±0.26, case; 4.75±0.29), stage 2 latency (control; 165±16.6, case; 216±38.68), stage 5 latency (control; 2.13±0.38, case; 3.47±0.64) and stage 5 duration (control; 21.15±2.42, case; 23.42±1.20) between two groups. Resuits of this experiment introduces the new critical time window for PTZ kindling.