Is amygdala kindling in rats a model for drug-resistant partial epilepsy?

Amygdala-kindled female rats were used to compare the effects of seven antiepileptic drugs that are clinically used for treatment of partial epilepsy with complex symptomatology, on generalized seizures, focal seizures, or electrographic seizure activity at the focus. As a second approach of drug evaluation, drug effects on mean latency, severity, and duration of the seizures were determined. Anticonvulsant potencies obtained were compared with those determined in the maximal electroshock seizure test in female rats. Phenobarbital, phenytoin, carbamazepine, valproic acid, diazepam, clonazepam, but not primidone dose-dependently suppressed generalized motor seizures in kindled rats; however, except for the benzodiazepines, ED50S were substantially higher than those determined in the maximal electroshock seizure test. Compared with their effect on generalized motor seizures, all drugs were much less potent in blocking focal seizures and afterdischarges recorded from the amygdala. The data suggest that with respect to behavioral and pharmacologic characteristics of the amygdala kindling model, fully kindled rats may be a useful model for drug-resistant complex partial seizures with secondary generalization. Results of experiments with novel inhibitors of GABA uptake, which were inactive in the maximal electroshock seizure test but highly potent against kindled seizures, suggest that such drugs might be more effective than current antiepileptic drugs for treatment of partial epilepsy.