title: A(2A) adenosine receptor binding parameters in platelets from patients affected by pathological gambling.
abstract: OBJECTIVE
  A structural and functional interaction between A(2A) adenosine receptors and D(2) dopamine receptors has been implicated in the pathophysiology of impulse control disorders. The aim of this study was to use platelet membranes to assess A(2A) adenosine receptor affinity and density in patients affected by pathological gambling (PG; which is classified as a specific impulse control disorder) with respect to those of control subjects.
  
  
  METHODS
  Twelve drug-free PG patients and 12 age- and sex-matched healthy controls were enrolled in the study. PG was diagnosed according to the Structured Clinical Interview for DSM-IV - Patient Version 2.0 and the South Oaks Gambling Screen. A(2A) adenosine receptor binding parameters were evaluated using a [(3)H]ZM(241385) binding assay; affinity and density (B(max)) were determined by means of saturation binding studies with platelet membranes.
  
  
  RESULTS
  The A(2A) adenosine receptor binding affinity was found to be significantly higher in patients affected by PG than in healthy subjects; in contrast, no significant differences in B(max) were observed between the 2 groups.
  
  
  CONCLUSIONS
  The elevated A(2A) adenosine receptor binding affinity in platelets from PG patients with respect to control subjects demonstrates for the first time a change in adenosine receptor parameters, and it suggests the involvement of the adenosine system in this pathology. The previously demonstrated hyperactivity of the dopamine system in PG may modulate the A(2A) adenosine receptor, supporting a role for this receptor as a peripheral marker of dopamine dysfunction. Because it is not possible to directly measure the D(2) dopamine receptor in human platelets, these data are particularly relevant to the detection of dopamine dysfunction.
authors.affiliation: Department of Psychiatry, Neurobiology, Pharmacology and Biotechnology, University of Pisa, Pisa, Italy. cmartini@farm.unipi.it
authors.forename: Claudia
authors.initials: C
authors.lastname: Martini
authors.forename: Simona
authors.initials: S
authors.lastname: Daniele
authors.forename: Michela
authors.initials: M
authors.lastname: Picchetti
authors.forename: Anna
authors.initials: A
authors.lastname: Panighini
authors.forename: Marina
authors.initials: M
authors.lastname: Carlini
authors.forename: Maria Letizia
authors.initials: ML
authors.lastname: Trincavelli
authors.forename: Daniela
authors.initials: D
authors.lastname: Cesari
authors.forename: Eleonora
authors.initials: E
authors.lastname: Da Pozzo
authors.forename: Francesca
authors.initials: F
authors.lastname: Golia
authors.forename: Liliana
authors.initials: L
authors.lastname: Dell'Osso
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000000981:diagnostic imaging / Q000378:metabolism*; D016022:Case-Control Studies; D005260:Female; D005715:Gambling / Q000097:blood / Q000000981:diagnostic imaging / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008297:Male; D011869:Radioligand Assay / Q000379:methods; D011877:Radionuclide Imaging; D043705:Receptor, Adenosine A2A / Q000378:metabolism*; D014227:Triazines / Q000097:blood*; D014230:Triazoles / Q000097:blood*; D014316:Tritium
chemical_list: D043705:Receptor, Adenosine A2A; D014227:Triazines; D014230:Triazoles; C097270:ZM 241385; D014316:Tritium