The D2/3 dopamine receptor in pathological gambling: a positron emission tomography study with [11C]‐(+)‐propyl‐hexahydro‐naphtho‐oxazin and [11C]raclopride. (3rd January 2013)

• Record Type: Journal Article
• Authors: Boileau, Isabelle; Payer, Doris; Chugani, Bindiya; Lobo, Daniela; Behzadi, Arian; Rusjan, Pablo M.; Houle, Sylvain; Wilson, Alan A.; Warsh, Jerry; Kish, Stephen J.; Zack, Martin
• Is Part Of: Addiction. Volume 108:Number 5(2013:May)
• Page Start: 953
• Page End: 963
• Publication Date: 2013-01-03
• Subjects: Alcoholism -- Periodicals; Drug addiction -- Periodicals; 616.86
• DOI: 10.1111/add.12066
• Languages: English
• ISSNs: 0965-2140

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <sec id="add12066-sec-0001" sec-type="section"> <title>Aims</title> <p>Pathological gambling (PG) shares diagnostic features with substance use disorder (SUD), but the neurochemical mechanisms underlying PG are poorly understood. Because dopamine (DA), a neurotransmitter implicated in reward and reinforcement, is probably involved, we used positron emission tomography (PET) to test whether PG is associated with abnormalities in D<sub>2</sub> and D<sub>3</sub> receptor levels, as observed in SUD.</p> </sec> <sec id="add12066-sec-0002" sec-type="section"> <title>Design</title> <p>Case–control study comparing PG to healthy control (HC) subjects.</p> </sec> <sec id="add12066-sec-0003" sec-type="section"> <title>Setting</title> <p>Academic research imaging centre.</p> </sec> <sec id="add12066-sec-0004" sec-type="section"> <title>Participants</title> <p>Thirteen non‐treatment‐seeking males meeting DSM‐IV criteria for PG, and 12 matched HC (11 of whom completed PET).</p> </sec> <sec id="add12066-sec-0005" sec-type="section"> <title>Measurements</title> <p>Two PET scans (one with the D<sub>3</sub> receptor preferring agonist [<sup>11</sup>C]‐(+)‐propyl‐hexahydro‐naphtho‐oxazin (PHNO) and the other with [<sup>11</sup>C]raclopride) to assess D<sub>2/3</sub> DA receptor availability, and behavioural measures (self‐report questionnaires and slot‐machine game) to assess subjective effects and relationships to PET measures.</p> </sec> <sec id="add12066-sec-0006" sec-type="section"> <title>Findings</title> <p>Binding of both radiotracers did not differ between groups in striatum or substantia nigra (SN) (all <italic>P</italic> > 0.1). Across PG, [<sup>11</sup>C]‐(+)‐PHNO binding in SN, where the signal is attributable primarily to D<sub>3</sub> receptors, correlated with gambling severity (<italic>r</italic> = 0.57, <italic>P</italic> = 0.04) and impulsiveness (<italic>r</italic> = 0.65, <italic>P</italic> = 0.03). In HC, [<sup>11</sup>C]raclopride binding in dorsal striatum correlated inversely with subjective effects of gambling (<italic>r</italic> = −0.70, <italic>P</italic> = 0.03) and impulsiveness (<italic>r</italic> = −0.70, <italic>P</italic> = 0.03).</p> </sec> <sec id="add12066-sec-0007" sec-type="section"> <title>Conclusions</title> <p>Unlike with substance use disorder, there appear to be no marked differences in D<sub>2</sub>/D<sub>3</sub> levels between healthy subjects and pathological gamblers, suggesting that low receptor availability may not be a necessary feature of addiction. However, relationships between [<sup>11</sup>C]‐(+)‐PHNO binding and gambling severity/impulsiveness suggests involvement of the D<sub>3</sub> receptor in impulsive/compulsive behaviours.</p> </sec> </abstract>