The hippocampal slice: a system for studying the pharmacology of seizures and for screening anticonvulsant drugs.

Interictal spikes with a configuration similar to that occurring in grand mal epilepsy were generated by the application of penicillin to a hippocampal slice preparation. This slice preparation has potential value for screening anticonvulsant drugs and for studying epileptic activity. The effect of anticonvulsant drugs on seizure activity was tested at concentrations comparable to reported clinical serum concentrations. Phenytoin and diazepam were maximally effective at concentrations of 20 microgram/ml and 3-4 microgram/ml, respectively, in good agreement with their effective concentrations in clinical practice. Phenobarbital was more potent (5 microgram/ml) and mesuximide (50% potent at 80 microgram/ml) was least effective.