Objective: 

Irregular synchronized neuronal discharges mediated by gap junctions have an important rol in epileptic seizures. Analysis of anticonvulsant drugs acting on gap junctions is still a priority in epilepsy research. Therefore, the present study was planned to investigate the effect of carbenoxolone (CBX), a gap junction blocker, on the anticonvulsant efficacy of phenytoin on pentylenetetrazole (PTZ) kindling model of epilepsy in rats.

Methods: 

Male Wistar albino rats, 14 weeks of age, were used. In the first step of study, animals were given PTZ 35 mg/kg intraperitoneally (i.p.) three times a week until kindling was produced. Then, permanent screw electrodes allowing EEG monitoring from awake rats, were implanted into the cranium of kindled rats. In this way, we were able to record EEG and evaluate seizure stage at the same time. In the second step, combination of CBX (40 mg/kg i.p.) and phenytoin (60 mg/kg, i.p.) was administered. The data analysis was performed using a one-way ANOVA with LSD post-hoc test.

Results: 

Phenytoin prevented generalized seizures by 66.6% and reduced seizure severity and score (P<0.05). The combination of CBX and phenytoin prevented generalized seizures by 66.6% and decreased seizure severity and score (P<0.05).

Conclusions: 

The results of this study show that there is no significant difference between CBX-phenytoin combination and phenytoin on all parameters. Thus, CBX does not increase the anticonvulsant efficacy of phenytoin in PTZ model of epilepsy in rats.