Dopaminergic potentiation of rTMS-induced motor cortex inhibition.
BACKGROUND
Experiments in animal models suggest that neuronal plasticity can be enhanced by dopaminergic receptor activation. The present study tested whether stimulation-induced plasticity of human motor cortex after low-frequency repetitive transcranial magnetic stimulation (rTMS) could be potentiated by a single oral dose of the combined D1/D2 receptor agonist pergolide.


METHODS
In a randomized, double-blind, placebo-controlled cross-over design, nine healthy young volunteers received .125 mg pergolide or placebo 2 hours before 1 Hz rTMS was applied for 20 min to the left primary motor cortex. In a control experiment 7 subjects received .125 mg pergolide 2 hours before sham rTMS. We used single-pulse TMS at rest to assess corticospinal excitability before and up to 24 min after rTMS.


RESULTS
Suppression of corticospinal excitability by 1 Hz rTMS was more pronounced after pergolide intake compared with placebo and lasted approximately 20 min after pergolide but only 5 min after placebo. No change of corticospinal excitability could be observed when sham rTMS was performed after pergolide intake.


CONCLUSIONS
The results suggest a possible role for dopaminergic potentiation of rTMS-induced neuroplasticity in experimental or therapeutic applications and should be considered when rTMS is applied in patients under medication with dopamine agonists or antagonists.
Lang
Nicolas
N
Department of Neurology, Christian-Albrechts University, Kiel, Germany. nlang@gwdg.de
Speck
Sascha
S
Harms
Jochen
J
Rothkegel
Holger
H
Paulus
Walter
W
Sommer
Martin
M
D000328:Adult; D018592:Cross-Over Studies; D004298:Dopamine / Q000378:metabolism*; D018491:Dopamine Agonists / Q000494:pharmacology; D004311:Double-Blind Method; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000187:drug effects / Q000502:physiology*; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D010479:Pergolide / Q000494:pharmacology; D050781:Transcranial Magnetic Stimulation
D018491:Dopamine Agonists; D010479:Pergolide; D004298:Dopamine