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BioMed Research International
Volume 2013 (2013), Article ID 497485, 9 pages
http://dx.doi.org/10.1155/2013/497485
Research Article

Locally Applied Valproate Enhances Survival in Rats after Neocortical Treatment with Tetanus Toxin and Cobalt Chloride

1Epilepsy Center, Department of Neurosurgery, University Hospital Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany
2Section of Clinical Neuropharmacology, Department of Neurosurgery, University Hospital Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany
3Department of Neurosurgery, University Hospital Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany

Received 30 April 2013; Revised 24 July 2013; Accepted 8 August 2013

Academic Editor: Mauro S. Oliveira

Copyright © 2013 Dirk-Matthias Altenmüller et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose. In neocortical epilepsies not satisfactorily responsive to systemic antiepileptic drug therapy, local application of antiepileptic agents onto the epileptic focus may enhance treatment efficacy and tolerability. We describe the effects of focally applied valproate (VPA) in a newly emerging rat model of neocortical epilepsy induced by tetanus toxin (TeT) plus cobalt chloride (CoCl2). Methods. In rats, VPA ( ) or sodium chloride (NaCl) ( ) containing polycaprolactone (PCL) implants were applied onto the right motor cortex treated before with a triple injection of 75 ng TeT plus 15 mg CoCl2. Video-EEG monitoring was performed with intracortical depth electrodes. Results. All rats randomized to the NaCl group died within one week after surgery. In contrast, the rats treated with local VPA survived significantly longer ( ). In both groups, witnessed deaths occurred in the context of seizures. At least of the rats surviving the first postoperative day developed neocortical epilepsy with recurrent spontaneous seizures. Conclusions. The novel TeT/CoCl2 approach targets at a new model of neocortical epilepsy in rats and allows the investigation of local epilepsy therapy strategies. In this vehicle-controlled study, local application of VPA significantly enhanced survival in rats, possibly by focal antiepileptic or antiepileptogenic mechanisms.