有冲动的感觉吗？据在健康志愿者身上所做的一项新的研究，做轻率鲁莽决定的倾向源自于多巴胺受体活性的降低以及随之而来的多巴胺在脑中释放的增加。 Joshua Buckholtz及其同事知道，这种特别的神经递质与人类的冲动行为有关，因此他们对32名实验参与者的脑子进行了扫描，在扫描的时候，这些受试者摄取了一剂安非他命以观察在多巴胺浓度与人类冲动行为之间的实际相关性。 研究人员用他们的数据创制了一个模型。在一篇Brevium的文章中，他们用该模型显示，那些有着很强冲动行为的人显示出多巴胺受体D2的结合活性较低，但他们对刺激（如安非他命）反应所释放出的多巴胺却有所增加。 这意味着，一个人的D2自体受体的可获得性差异可帮助预测这个人所展现的冲动行为的表达。 由于冲动还与药物滥用及以往的成瘾性有关，研究人员提示，这种D2活性的降低（以及接着发生的在其它部位多巴胺释放的增加）可能同样也与药物的成瘾性有关。
Article #7: "Dopaminergic Network Differences in Human Impulsivity," by J.W. Buckholtz; M.T. Treadway; R.L. Cowan; N.D. Woodward; R. Li; M.S. Ansari; R.M. Baldwin; A.N. Schwartzman; E.S. Shelby; C.E. Smith; R.M. Kessler; D.H. Zald at Vanderbilt University in Nashville, TN.
Science 30 July 2010:
Vol. 329. no. 5991, p. 532
DOI: 10.1126/science.1185778
Brevia
Dopaminergic Network Differences in Human Impulsivity
Joshua W. Buckholtz,1,2,*, Michael T. Treadway,1, Ronald L. Cowan,3,4 Neil D. Woodward,3,4 Rui Li,5 M. Sib Ansari,5 Ronald M. Baldwin,5 Ashley N. Schwartzman,1 Evan S. Shelby,1 Clarence E. Smith,3 Robert M. Kessler,5 David H. Zald1,3
Dopamine (DA) has long been implicated in impulsivity, but the precise mechanisms linking human variability in DA signaling to differences in impulsive traits remain largely unknown. By using a dual-scan positron emission tomography approach in healthy human volunteers with amphetamine and the D2/D3 ligand [18F]fallypride, we found that higher levels of trait impulsivity were predicted by diminished midbrain D2/D3 autoreceptor binding and greater amphetamine-induced DA release in the striatum, which was in turn associated with stimulant craving. Path analysis confirmed that the impact of decreased midbrain D2/D3 autoreceptor availability on trait impulsivity is mediated in part through its effect on stimulated striatal DA release.
