title: Modulation of human motor cortex excitability by valproate.
abstract: BACKGROUND
  Valproate is widely used in the treatment of epilepsy, bipolar disorder, and chronic pain disorders, but its exact mechanisms of action is still incompletely understood.
  
  
  OBJECTIVE
  Here we used transcranial magnetic stimulation to explore effects of a single dose of 800 mg valproate on motor cortex excitability in healthy volunteers.
  
  
  METHODS
  Motor threshold, peripheral maximum M-wave, cortical silent period short intracortical inhibition, intracortical facilitation, and motor evoked potential recruitment were assessed before and 1.5 h after the administration of valproate in 15 (eight male, seven female) healthy volunteers.
  
  
  RESULTS
  None of the measures of cortical excitability were found to be altered significantly after valproate.
  
  
  CONCLUSIONS
  These results are in line with previous findings of unaffected intracortical excitability after a single dose of valproate, suggesting that valproate's immediate in vivo actions do not resemble the effects of classic GABAergic compounds.
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, University of Regensburg, Universitaetsstraße 84, 93053 Regensburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Zunhammer
authors.forename: Berthold
authors.initials: B
authors.lastname: Langguth
authors.forename: Michael
authors.initials: M
authors.lastname: Landgrebe
authors.forename: Elmar
authors.initials: E
authors.lastname: Frank
authors.forename: Sabine
authors.initials: S
authors.lastname: Müller
authors.forename: Julia
authors.initials: J
authors.lastname: Burger
authors.forename: Philipp G
authors.initials: PG
authors.lastname: Sand
authors.forename: Peter
authors.initials: P
authors.lastname: Eichhammer
authors.forename: Göran
authors.initials: G
authors.lastname: Hajak
mesh_terms: D000328:Adult; D000927:Anticonvulsants / Q000494:pharmacology*; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000187:drug effects* / Q000502:physiology; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D014635:Valproic Acid / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D000927:Anticonvulsants; D014635:Valproic Acid