A pharmacological study in the kindling model of epilepsy

The anticonvulsant properties of carbamazepine were evaluated in the kindled amygdaloid seizure model in rats. Carbamazepine significantly raised the threshold for seizures, reduced the duration of elicited afterdischarges and attenuated the severity of seizures in previously-kindled rats, at doses that did not cause sedation or ataxia. A similar reduction in the duration of elicited afterdischarges and severity of seizures was seen after suprathreshold stimulation (400 mu A) with doses of carbamazepine that were without obvious sedative or ataxic effects. After acute intraperitoneal injections (solvent = 2% Tween-80 and 70% propylene glycol), the maximum anticonvulsant effectiveness against suprathreshold stimulation was seen at 30 min. When administered daily (13 days) during acquisition or development of kindling, carbamazepine (25 and 50 mg/kg, i.p.) had variable effects on kindling. Neither dose consistently reduced the duration of elicited afterdischarges during the acquisition phase. Both groups tended to reduce the developing seizure, with the smaller dose of carbamazepine (25 mg/kg) resulting in a more consistent and significant reduction in severity of seizures. No significant differences in number of daily stimulations needed to reach fully kindled seizures were found. Previous studies have reported variable results with carbamazepine and the kindled amygdaloid seizure in rats. The present study provides a comprehensive evaluation of carbamazepine in this model of epilepsy and discusses the results with regard to the finding reported previously.