Cabergoline reverses cortical hyperexcitability in patients with restless legs syndrome.
OBJECTIVE
To reverse the profile of abnormal intracortical excitability in patients with restless legs syndrome (RLS) by administering the dopaminergic agonist cabergoline.


METHODS
The effects of this drug on motor cortex excitability were examined with a range of transcranial magnetic stimulation (TMS) protocols before and after administration of cabergoline over a period of 4 weeks in 14 patients with RLS and in 15 healthy volunteers. Measures of cortical excitability included central motor conduction time; resting and active motor threshold to TMS; duration of the cortical silent period; short latency intracortical inhibition (SICI) and intracortical facilitation using a paired-pulse TMS technique.


RESULTS
Short latency intracortical inhibition was significantly reduced in RLS patients compared with the controls and this abnormal profile was reversed by treatment with cabergoline; the other TMS parameters did not differ significantly from the controls and remained unaffected after treatment with cabergoline. Cabergoline had no effect on cortical excitability of the normal subjects.


CONCLUSIONS
As dopaminergic drugs are known to increase SICI, our findings suggest that RLS may be caused by a central nervous system dopaminergic dysfunction. This study demonstrates that the cortical hyperexcitability of RLS is reversed by cabergoline, and provides physiological evidence that this dopamine agonist may be a potentially efficacious option for the treatment of RLS.
Nardone
R
R
Department of Neurology, F. Tappeiner Hospital, Merano, Italy. raffaele.nardone@asbmeran-o.it
Ausserer
H
H
Bratti
A
A
Covi
M
M
Lochner
P
P
Marth
R
R
Tezzon
F
F
D000328:Adult; D000368:Aged; D001927:Brain Diseases / Q000150:complications* / Q000188:drug therapy* / Q000503:physiopathology; D000077465:Cabergoline; D004298:Dopamine / Q000378:metabolism; D018491:Dopamine Agonists / Q000008:administration & dosage / Q000009:adverse effects; D004873:Ergolines / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008875:Middle Aged; D009044:Motor Cortex / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D009431:Neural Conduction / Q000187:drug effects / Q000502:physiology; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D011712:Pyramidal Tracts / Q000187:drug effects / Q000503:physiopathology; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012148:Restless Legs Syndrome / Q000188:drug therapy* / Q000209:etiology* / Q000503:physiopathology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D050781:Transcranial Magnetic Stimulation; D016896:Treatment Outcome
D018491:Dopamine Agonists; D004873:Ergolines; D000077465:Cabergoline; D004298:Dopamine