Dopamine D1 receptors in cocaine dependence measured with PET and the choice to self-administer cocaine

The goal of this study was to determine D"1 receptor availability in human cocaine-dependent (CD) subjects and matched healthy controls (HCs). In addition, the CD subjects performed cocaine self-administration sessions in order to explore the association between D"1 receptor availability and cocaine-seeking behavior. Twenty-five CD subjects (40±4 years, 19M6 F) and 23 matched HCs (38±4 years, 19M4F) were scanned with PET and the radiotracer ¹¹CNNC 112. During the cocaine self-administration sessions, CD volunteers were given the choice to self-administer cocaine (0, 6, and 12mg) or to receive a monetary voucher worth 5. D"1 receptor availability was measured in the limbic, associative, and sensori-motor striatum in addition to cortical brain regions. No difference in D"1 receptor availability was seen between the two groups. A negative association was seen between D"1 receptor BP(ND) in the limbic striatum and the choice for the 6mg dose of cocaine (r0.47, p0.02, corrected for age). These results do not support the hypothesis that cocaine dependence is associated with a reduction in D"1 receptor availability in the striatum. However, within the CD subjects, low D"1 receptor availability in the ventral striatum was associated with the choice to self-administer cocaine, suggesting that low D"1 receptor availability may be associated with an increased risk of relapse in cocaine dependence.