D₂-like dopamine receptors in animals and humans have been shown to be linked to impulsive behaviors that are highly relevant for several psychiatric disorders. Here, we investigate the relationship between the fronto-striatal D₂/D₃ dopamine receptor availability and response inhibition in a selected population of healthy OPRM1 G-allele carriers. Twenty-two participants successively underwent blood-oxygen level dependent functional magnetic resonance imaging (fMRI) while performing a stop-signal task and a separate positron emission tomography (PET) scan. Striatal and extrastriatal D₂/D₃ dopamine receptor availability was measured using the radiotracer [¹⁸F]fallypride. Caudate D₂/D₃ dopamine receptor availability positively correlated with stopping-related fronto-striatal fMRI activation. In addition, right prefrontal D₂/D₃ dopamine receptor availability correlated positively with stopping-related striatal fMRI BOLD signal. Our study partially replicates previous findings on correlations between striatal D₂/D₃ dopamine receptor availability and response inhibition in a population selected for its genetic determination of dopamine response to alcohol and as a modulator of impulse control via the endogenous opioid system. We confirm the important role of D₂/D₃ dopamine receptor availability in the fronto-striatal neural circuit for response inhibition. Moreover, we extend previous findings suggesting that dopamine receptor availability in the right inferior frontal cortex, a crucial region of the stopping network, is also strongly associated with stopping-related striatal fMRI activity in healthy OPRM1 G-allele carriers.

动物和人类中的D ₂样多巴胺受体已被证明与与几种精神疾病高度相关的冲动行为有关。在这里，我们研究了选定的健康 OPRM1 G 等位基因携带者群体中额纹状体 D ₂ /D _{3多巴胺受体可用性与反应抑制之间的关系。}22 名参与者在执行停止信号任务和单独的正电子发射断层扫描 (PET) 扫描时相继接受了血氧水平依赖性功能磁共振成像 (fMRI)。^{使用放射性示踪剂 [ 18} F]fallypride测量纹状体和纹状体外 D ₂ /D ₃多巴胺受体的可用性。尾状D₂ /D ₃多巴胺受体可用性与停止相关的额纹状体fMRI激活呈正相关。此外，右前额叶 D ₂ /D ₃多巴胺受体可用性与停止相关的纹状体 fMRI BOLD 信号呈正相关。我们的研究部分复制了先前关于纹状体 D ₂ /D ₃多巴胺受体可用性和反应抑制之间相关性的研究结果，这些研究结果在被选择用于其对酒精的多巴胺反应的遗传测定和作为通过内源性阿片系统的脉冲控制调节剂的人群中。我们确认 D ₂ /D _{3的重要作用}额纹状体神经回路中用于抑制反应的多巴胺受体可用性。此外，我们扩展了先前的研究结果，表明右下额叶皮层（停止网络的关键区域）中的多巴胺受体可用性也与健康 OPRM1 G 等位基因携带者的停止相关纹状体 fMRI 活动密切相关。