doi:10.1093/brain/awl163 Brain (2006), 129, 2017–2028 Support for dopaminergic hypoactivity in restless legs syndrome: a PET study on D2-receptor binding Simon Cˇ ervenka,1 Sven E. Pa˚lhagen,2 Robert A. Comley,4 Georgios Panagiotidis,3 Zsolt Csele´nyi,1 Julian C. Matthews,4,5 Robert Y. Lai,6 Christer Halldin1 and Lars Farde1 1Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet, Karolinska University Hospital Solna, 2Department of Neurology, 3Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska University Hospital Huddinge, Stockholm, Sweden, 4Translational Medicine and Genetics, GlaxoSmithKline, Cambridge, 5The University of Manchester, Wolfson Molecular Imaging Centre, Manchester and 6Neurology Discovery Medicine, GlaxoSmithKline, Harlow, UK Correspondence to: Simon Cˇ ervenka, Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet, Karolinska University Hospital Solna, Building R5, SE-171 76 Stockholm, Sweden E-mail:
[email protected] Clinical observations support a central role of the dopamine system in restless legs syndrome (RLS) but previous imaging studies of striatal dopamine D2-receptors have yielded inconclusive results. Extrastriatal dopaminergic function has hitherto not been investigated. Sixteen RLS patients naı¨ve to dopaminergic drugs and sixteen matched control subjects were examined with PET. [11C]Raclopride and [11C]FLB 457 were used to estimate D2-receptor availability in striatum and extrastriatal regions, respectively. Examinations were performed both in the morning (starting between 10:00 and 12:00 h) and evening (starting at 18:00 h). Measures were taken to monitor and control for head movement during data acquisition. In the striatum, patients had significantly higher [11C]raclopride binding potential (BP) values than controls.