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Proconvulsant Actions of Intrahippocampal Botulinum Neurotoxin B in the Rat
Neuroscience (2013)
  • Sonja Bröer, University of California - Davis
  • Dorota Zolkowska, University of California - Davis
  • Manuela Gernert
  • Michael A. Rogawski, University of California - Davis
Botulinum neurotoxins (BoNTs) may affect the excitability of brain circuits by inhibiting neurotransmitter release at central synapses. There is evidence that local delivery of BoNT serotypes A and E, which target synaptosomal-associated protein 25, a component of the release machinery specific to excitatory synapses, can inhibit seizure generation. BoNT serotype B (BoNT/B) targets VAMP2, which is expressed in both excitatory and inhibitory terminals. Here we assessed the effects of unilateral intrahippocampal infusion of BoNT/B in the rat on intravenous pentylenetetrazol (PTZ) seizure thresholds, and on the expression of spontaneous behavioral and electrographic seizures. Infusion of BoNT/B (500 and 1000 Unit) by convection-enhanced delivery caused a reduction in myoclonic twitch and clonic seizure thresholds in response to intravenous PTZ beginning about 6 days after the infusion. Handling-evoked and spontaneous convulsive seizures were observed in many BoNT/B-treated animals but not in vehicle-treated controls. Spontaneous electrographic seizure discharges were recorded in animals implanted for depth electroencephalogram recording in the dentate gyrus that received local BoNT/B infusion. In addition, there was an increased frequency of interictal epileptiform spikes and sharp waves at the same recording site. BoNT/B-treated animals also exhibited tactile hyperresponsivity in comparison with vehicle-treated controls. This is the first demonstration that BoNT/B causes a delayed proconvulsant action when infused into the hippocampus. Local infusion of BoNT/B could be useful as a focal epilepsy model.
Publication Date
November 12, 2013
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Citation Information
Sonja Bröer, Dorota Zolkowska, Manuela Gernert and Michael A. Rogawski. "Proconvulsant Actions of Intrahippocampal Botulinum Neurotoxin B in the Rat" Neuroscience Vol. 252 (2013)
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