title: Vagus nerve stimulation has antidepressant effects in the kainic acid model for temporal lobe epilepsy.
abstract: BACKGROUND
  Depression is the most common psychiatric comorbidity in epilepsy patients. The lack of success with current pharmacological interventions for this patient population, highlights the importance of optimizing non-pharmacological neuromodulatory treatments such as vagus nerve stimulation (VNS). Studies on the antidepressant effect of VNS in epilepsy patients may be confounded by concurrent anti-epileptic drug therapy. To date, studies in epilepsy models overcoming this problem are lacking.
  
  
  OBJECTIVE
  We investigated whether VNS affects anhedonia, a key symptom of major depression, in the kainic acid rat model for temporal lobe epilepsy.
  
  
  METHODS
  Anhedonia was assessed in kainic acid (KA) and saline (SAL) injected rats using the saccharin preference test (SPT). To exclude differences in taste perception, the quinine aversion test (QAT) was performed. Both groups were randomly subdivided in a VNS and a SHAM group, yielding 4 experimental arms: KA-VNS, KA-SHAM, SAL-VNS and SAL-SHAM. Both VNS groups received 2 weeks of VNS, while the SHAM groups were not stimulated. Thereafter, the SPT and QAT were repeated.
  
  
  RESULTS
  Saccharin preference was significantly reduced in the KA compared to the SAL rats (P < 0.05), without differences in quinine aversion. Two weeks of VNS significantly increased the saccharin preference in the KA-VNS group (P < 0.05), while it had no effect on quinine aversion. No effects of VNS or SHAM were found in the other groups.
  
  
  CONCLUSIONS
  The KA rats displayed anhedonia which was significantly decreased by VNS, indicating that this neuromodulatory treatment could likewise diminish depressive symptoms in patients suffering from temporal lobe epilepsy and comorbid depression.
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology (LCEN3), Ghent University, Department of Neurology, Institute for Neuroscience, Ghent, Belgium. Electronic address: Annelies.Grimonprez@ugent.be.
authors.forename: Annelies
authors.initials: A
authors.lastname: Grimonprez
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology (LCEN3), Ghent University, Department of Neurology, Institute for Neuroscience, Ghent, Belgium.
authors.forename: Robrecht
authors.initials: R
authors.lastname: Raedt
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology (LCEN3), Ghent University, Department of Neurology, Institute for Neuroscience, Ghent, Belgium.
authors.forename: Ine
authors.initials: I
authors.lastname: Dauwe
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology (LCEN3), Ghent University, Department of Neurology, Institute for Neuroscience, Ghent, Belgium.
authors.forename: Lies
authors.initials: L
authors.lastname: Mollet
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology (LCEN3), Ghent University, Department of Neurology, Institute for Neuroscience, Ghent, Belgium.
authors.forename: Lars Emil
authors.initials: LE
authors.lastname: Larsen
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology (LCEN3), Ghent University, Department of Neurology, Institute for Neuroscience, Ghent, Belgium.
authors.forename: Alfred
authors.initials: A
authors.lastname: Meurs
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology (LCEN3), Ghent University, Department of Neurology, Institute for Neuroscience, Ghent, Belgium.
authors.forename: Veerle
authors.initials: V
authors.lastname: De Herdt
authors.affiliation: Swammerdam Institute of Life Sciences, Department of Neurobiology, University of Amsterdam, The Netherlands.
authors.forename: Wytse
authors.initials: W
authors.lastname: Wadman
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology (LCEN3), Ghent University, Department of Neurology, Institute for Neuroscience, Ghent, Belgium.
authors.forename: Jean
authors.initials: J
authors.lastname: Delbeke
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology (LCEN3), Ghent University, Department of Neurology, Institute for Neuroscience, Ghent, Belgium.
authors.forename: Kristl
authors.initials: K
authors.lastname: Vonck
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology (LCEN3), Ghent University, Department of Neurology, Institute for Neuroscience, Ghent, Belgium.
authors.forename: Paul
authors.initials: P
authors.lastname: Boon
mesh_terms: D059445:Anhedonia; D000818:Animals; D002755:Choice Behavior; D003865:Major Depressive Disorder / Q000150:complications / Q000628:therapy*; D004195:Disease Models, Animal; D004833:Epilepsy, Temporal Lobe / Q000139:chemically induced / Q000150:complications / Q000628:therapy*; D007608:Kainic Acid; D008297:Male; D051381:Rats; D013226:Status Epilepticus / Q000139:chemically induced / Q000150:complications / Q000628:therapy; D055536:Vagus Nerve Stimulation
chemical_list: D007608:Kainic Acid
keywords: Anhedonia; Depression; Kainic acid model; Temporal lobe epilepsy; Vagus nerve stimulation