Antiepileptic effects of botulinum neurotoxin E

Experimental studies suggest that the delivery of antiepileptic agents into the seizure focus might be of potential utility for the treatment of focal- onset epilepsies. Botulinum neurotoxin E ( BoNT/ E) causes a prolonged inhibition of neurotransmitter release after its specific cleavage of the synaptic protein synaptosomal- associated protein of 25 kDa ( SNAP- 25). Here, we show that BoNT/ E injected into the rat hippocampus inhibits glutamate release and blocks spike activity of pyramidal neurons. BoNT/ E effects persist for at least 3 weeks, as determined by immunodetection of cleaved SNAP- 25 and loss of intact SNAP- 25. The delivery of BoNT/ E to the rat hippocampus dramatically reduces both focal and generalized kainic acid- induced seizures as documented by behavioral and electrographic analysis. BoNT/ E treatment also prevents neuronal loss and long- term cognitive deficits associated with kainic acid seizures. Moreover, BoNT/ Einjected rats require 50% more electrical stimulations to reach stage 5 of kindling, thus indicating a delayed epileptogenesis. Weconclude that BoNT/ E delivery to the hippocampus is both antiictal and antiepileptogenic in experimental models of epilepsy.Experimental studies suggest that the delivery of antiepileptic agents into the seizure focus might be of potential utility for the treatment of focal- onset epilepsies. Botulinum neurotoxin E ( BoNT/ E) causes a prolonged inhibition of neurotransmitter release after its specific cleavage of the synaptic protein synaptosomal- associated protein of 25 kDa ( SNAP- 25). Here, we show that BoNT/ E injected into the rat hippocampus inhibits glutamate release and blocks spike activity of pyramidal neurons. BoNT/ E effects persist for at least 3 weeks, as determined by immunodetection of cleaved SNAP- 25 and loss of intact SNAP- 25. The delivery of BoNT/ E to the rat hippocampus dramatically reduces both focal and generalized kainic acid- induced seizures as documented by behavioral and electrographic analysis. BoNT/ E treatment also prevents neuronal loss and long- term cognitive deficits associated with kainic acid seizures. Moreover, BoNT/ Einjected rats require 50% more electrical stimulations to reach stage 5 of kindling, thus indicating a delayed epileptogenesis. Weconclude that BoNT/ E delivery to the hippocampus is both antiictal and antiepileptogenic in experimental models of epilepsy.