title: Lamotrigine and valproic acid have different effects on motorcortical neuronal excitability.
abstract: To investigate different cortical effects of lamotrigine and valproic acid, 30 paid healthy adult men were given, in a randomized/blinded fashion on three separate days (separated by a week), either a single dose of lamotrigine 325 mg, or a single dose of valproic acid 1,250 mg, or placebo. Resting motor threshold (RMT), cortical silent period (CSP) and motor evoked potential recruitment curves (RC) were assessed at baseline and 3 h after administration of each medication (or placebo). Lamotrigine caused a significant increase (63.32 vs. 69.25) in the RMT, compared with an insignificant increase following valproic acid (62.50 vs. 63.35), and a decrease (62.60 vs. 62.36) following placebo (F (2,26) = 18.58, P < 0.0001). No significant difference in CSP was found between placebo and drugs (F (2,26) = 0.119, P > 0.05). RCs were significantly suppressed by lamotrigine (t = 2.07, P < 0.05) and enhanced by valproic acid (t = 2.39, P < 0.05). Lamotrigine and valproic acid have different effects on cortical neuronal excitability as demonstrated by TMS.
authors.affiliation: Brain Stimulation Laboratory, Department of Psychiatry, Medical University of South Carolina, MUSC IOP, 502 N, 67 President Street, Charleston, SC, 29425, USA. lixi@musc.edu
authors.forename: Xingbao
authors.initials: X
authors.lastname: Li
authors.forename: Raffaella
authors.initials: R
authors.lastname: Ricci
authors.forename: Charles H
authors.initials: CH
authors.lastname: Large
authors.forename: Berry
authors.initials: B
authors.lastname: Anderson
authors.forename: Ziad
authors.initials: Z
authors.lastname: Nahas
authors.forename: Mark S
authors.initials: MS
authors.lastname: George
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D002491:Central Nervous System Agents / Q000494:pharmacology*; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000187:drug effects; D006801:Humans; D000077213:Lamotrigine; D016014:Linear Models; D008297:Male; D009043:Motor Activity; D009044:Motor Cortex / Q000187:drug effects* / Q000502:physiology; D050781:Transcranial Magnetic Stimulation; D014227:Triazines / Q000494:pharmacology*; D014635:Valproic Acid / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D002491:Central Nervous System Agents; D014227:Triazines; D014635:Valproic Acid; D000077213:Lamotrigine