Influence of the N-methyl-D-aspartate antagonist memantine on human motor cortex excitability.
The aim of our study was to investigate the effect of the N-methyl-D-aspartate (NMDA) antagonist memantine on motor excitability in humans. Seven healthy volunteers received memantine or placebo, respectively, over a period of 8 days. At day 8, transcranial magnetic stimulation (TMS) was performed using a paired pulses paradigm in order to assess intracortical inhibition and facilitation. Additionally, motor threshold and silent period duration after TMS were measured as well as M waves, F waves and peripheral silent period after electrical peripheral nerve stimulation. Intracortical inhibition was enhanced, and intracortical facilitation reduced after memantine ingestion in comparison to placebo, whereas no significant difference could be observed regarding the other neurophysiological parameters. We conclude that the NMDA receptor is involved in the regulation of excitability of intracortical interneuronal circuits.
Schwenkreis
P
P
Department of Neurology, Ruhr-University Bochum, BG-Kliniken Bergmannsheil, Germany. peter.u.schwenkreis@ruhr-uni-bochum.de
Witscher
K
K
Janssen
F
F
Addo
A
A
Dertwinkel
R
R
Zenz
M
M
Malin
J P
JP
Tegenthoff
M
M
D000328:Adult; D018592:Cross-Over Studies; D004056:Differential Threshold / Q000187:drug effects; D004311:Double-Blind Method; D004558:Electric Stimulation; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008280:Magnetics; D008297:Male; D008559:Memantine / Q000494:pharmacology*; D009044:Motor Cortex / Q000187:drug effects* / Q000502:physiology; D016202:N-Methylaspartate / Q000037:antagonists & inhibitors*; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D010812:Physical Stimulation / Q000379:methods; D014459:Ulnar Nerve / Q000502:physiology
D018691:Excitatory Amino Acid Antagonists; D016202:N-Methylaspartate; D008559:Memantine