Increased synaptic dopamine in the putamen in restless legs syndrome

Christopher J. Earley, Hiroto Kuwabara, Dean Foster Wong, Charlene Gamaldo, Rachel E. Salas, James R. Brašíc, Hayden T Ravert, Robert F. Dannals, Richard P. Allen

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


Study Objectives: Prior studies using positron emission tomography (PET) or single-photon emission computed tomography techniques have reported inconsistent findings regarding differences between patients with restless legs syndrome (RLS) and control patients in the striatal dopamine-2 receptor (D2R) binding potentials (BP). D2R-BP does reflect receptor-ligand interactions such as receptor affinity (Kd) and density (βmax) or neurotransmitter synaptic concentrations. Thus, differences in D2R-BP reflect changes in these primary factors. PET techniques are currently available to estimate D2R βmax and Kd. Design: Separate morning and evening PET scans were performed. The D2R-BP were measured in basal ganglia using [11C]raclopride. Setting: Academic medical center. Patients or Participants: Thirty-one patients with primary RLS and 36 age- and sex-matched control patients completed the study. Measures and Results: Patients with RLS had lower D2R-BP in putamen and caudate but not the ventral striatum. A subgroups analysis of those RLS patients who had not previously taken dopaminergic medications continued to show a significantly lower D2R-BP in the posterior putamen. D2R-BP did not differ between night and day for either group. D2R βmax and Kd did not differ significantly between patients with RLS and control patients but did show a strong and significant increase at night in the ventral striatum. Primary and secondary clinical measures of disease status failed to show any relation to D2R in any brain region. Conclusions: Given the lack of any difference in either βmax or Kd and the prior studies supporting an increase in presynaptic dopaminergic activity, the current changes found in D2R-BP likely reflect an increase in synaptic dopamine.

Original languageEnglish (US)
Pages (from-to)51-57
Number of pages7
Issue number1
StatePublished - Jan 1 2013


  • Diurnal
  • Dopamine receptor
  • Positron emission tomography
  • Restless legs syndrome
  • Striatum

ASJC Scopus subject areas

  • Clinical Neurology
  • Physiology (medical)


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