SPECT imaging of striatal pre- and postsynaptic dopaminergic status in restless legs syndrome with periodic leg movements in sleep

J Neurol. 2002 Feb;249(2):164-70. doi: 10.1007/pl00007859.


Restless legs syndrome (RLS) is a common sleep-related disorder principally characterised by leg paresthesia associated with an irresistible urge to move. A majority of RLS patients experience periodic leg movements during sleep (PLMS) and wakefulness. Pharmacological evidence suggests that RLS-PLMS may be caused by a central nervous system dopaminergic (DA) dysfunction. The aim of the present study was to evaluate the striatal pre- and postsynaptic DA status in patients suffering from both RLS and PLMS, by means of [123I] beta-CIT and [123I]IBZM SPECT respectively. Ten drug-naïve patients and ten age-matched controls participated in this study. All participants were recorded for at least one night of polysomnography before the SPECT studies. No difference was seen in DA transporter ([123I] beta-CIT) binding between RLS-PLMS patients (MD=4.89) and controls (MD=4.81; p=0.81). The study of the striatal D2-receptor binding ([123I]IBZM) revealed a significantly lower binding in patients (MD= 1.72) compared with controls (MD=1.85; p=0.006). These results support the hypothesis that a central DA dysfunction is involved in the physiopathology of RLS-PLMS. Several mechanisms may be responsible for the decrease of the D2-receptor binding. However, since [123I] beta-CIT binding is normal, a decreased number of D2-receptors or a decreased affinity of D2-receptors for [123I]IBZM is more likely than an increased level of synaptic DA with attendant downregulation of D2-receptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Benzamides
  • Binding, Competitive / drug effects
  • Binding, Competitive / physiology
  • Cocaine / analogs & derivatives
  • Dopamine / metabolism*
  • Dopamine Plasma Membrane Transport Proteins
  • Female
  • Functional Laterality / drug effects
  • Functional Laterality / physiology
  • Humans
  • Male
  • Membrane Glycoproteins*
  • Membrane Transport Proteins / drug effects
  • Membrane Transport Proteins / metabolism
  • Middle Aged
  • Neostriatum / diagnostic imaging*
  • Neostriatum / physiopathology
  • Nerve Tissue Proteins*
  • Presynaptic Terminals / diagnostic imaging*
  • Presynaptic Terminals / metabolism
  • Prospective Studies
  • Pyrrolidines
  • Restless Legs Syndrome / diagnostic imaging*
  • Restless Legs Syndrome / physiopathology
  • Synaptic Membranes / diagnostic imaging*
  • Synaptic Membranes / metabolism
  • Synaptic Transmission / physiology*
  • Tomography, Emission-Computed, Single-Photon


  • Benzamides
  • Dopamine Plasma Membrane Transport Proteins
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Nerve Tissue Proteins
  • Pyrrolidines
  • 2beta-carbomethoxy-3beta-(4-iodophenyl)tropane
  • 3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide
  • Cocaine
  • Dopamine