Effect of zonisamide (CI-912) on a synaptic system model.
The effect of the experimental antiepileptic drug zonisamide (1,2-benzisoxazole-3-methanesulfonamide, ZNS) on the trigeminal complex of cats was compared with the effect of established antiepileptic drugs. Intravenous administration of 10-40 mg/kg ZNS significantly depresses descending excitatory mechanisms, as well as segmental and descending inhibitory mechanisms, but has only a minor effect on segmental excitatory mechanisms. This spectrum of activity is similar to that of valproate, and suggests that ZNS should also be a broad-spectrum antiepileptic drug. In agreement with our experimental observations, it has been found that ZNS is effective against complex partial, generalized tonic clonic, and myoclonic seizures. The antiepileptic profile of ZNS in conventional screening tests resembles that of carbamazepine (CBZ) and phenytoin. However, CBZ exacerbates rather than prevents myoclonic seizures. Our experimental model thus provides a more accurate prediction of ZNS's clinical spectrum of activity. The relationship of these findings to the mechanism of action of antiepileptic drugs is discussed.
Department of Neurology, University of Pittsburgh School of Medicine, Pennsylvania 15261.
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D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology* / Q000627:therapeutic use; D002415:Cats; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D004558:Electric Stimulation; D007555:Isoxazoles / Q000494:pharmacology* / Q000627:therapeutic use; D008839:Microelectrodes; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010080:Oxazoles / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012640:Seizures / Q000188:drug therapy* / Q000503:physiopathology; D013569:Synapses / Q000187:drug effects* / Q000502:physiology; D014279:Trigeminal Nucleus, Spinal / Q000187:drug effects / Q000502:physiology; D000078305:Zonisamide
D000927:Anticonvulsants; D007555:Isoxazoles; D010080:Oxazoles; D000078305:Zonisamide