Experimental models of epilepsy

Abstract

50 million persons worldwide suffer from epilepsy, and 20-30% of those afflicted have seizures that are resistant to treatment with the currently available antiepileptic drugs. Studies on the epilepsy have been done in experimental models. For development of new and effective antiepileptic drugs, and the study of mechanisms of the epilepsies requires appropriate experimental models. An ideal model for epilepsy should show the following characteristics: (1) the development of spontaneously occuring recurrent seizures; (2) seizure types similar to seizure types occurring in human epilepsy; (3) EEG Pattern similar to EEG of the respective seizure in humans; (4) high seizure frequency to allow acute and chronic drug efficacy tests; (5) pharmacokinetics of antiepileptic drugs similar to those in humans; (6) effective plasma and brain concentrations of antiepileptic drugs similar to those required for control of the respective seizure in humans. Animal models of experimental epilepsy can be divided into three classes: (1) models induced by convulsant drugs or by an electrical. stimulation; (2) models of reflex epilepsies; (3) models of idiopathic epilepsies. Animal models of epilepsy taken from each of these three classes are briefly reviewed. The models in the first class are widely used for evaluation of new anticonvulsant drugs. The EEG patterns and pharmacological properties of kindled seizures are similar to those of psychomotor epilepsy in humans. Various animal species exhibit reflex epilepsies. Myoclonic seizures are induced by photic stimulation in Papio-papio baboons; tonic-clonic seizures are induced by auditory stimuli in certain strains of mice and rats. Photosensitive and febrile seizures have been reported in fowl. Most antiepileptic drugs are effective in reflex epilepsies. Idiopathic epilepsy is most common in dogs. As a conclusion, the suitable animal models are most important for an easier treatment of the epilepsies and a better understanding of the basic mechanisms of the epileptic phenomena.