一项研究提示，对酒精依赖的个体的脑多巴胺水平在戒酒期间增加。这个以醉酒和戒酒的循环为特征的慢性酒瘾诱导大脑的依赖于神经递质多巴胺的奖赏路径产生变化。Natalie Hirth及其同事研究了酒精依赖的个体在戒酒期间出现的多巴胺调控的变化。这组作者比较了喝酒很多的人和几乎不喝酒的人的尸检大脑组织样本的3种不同的多巴胺结合分子的配位体结合。
喝酒很多的人和喝酒少人的与D2样受体的结合是类似的，但是喝酒很多的人的与D1受体以及多巴胺转运体的配位体结合减少了。这些结果表明了一个与酒瘾有关的超多巴胺能的状态，其特征是多巴胺水平高。这组作者在酒瘾的大鼠模型中证明了类似的效应。就在立即戒酒之后，来自这些大鼠的大脑组织样本表明了多巴胺水平低，但是在戒酒期间，多巴胺水平指标增加。这种增加的多巴胺水平与大鼠的多动以及寻求酒精的行为增强有关联。
这组作者提出，戒酒之后大脑多巴胺立即水平下降，而在之后长的戒酒期多巴胺增加到超多巴胺能状态。这组作者说，发现与多巴胺水平增加有关的行为可能有助于识别出预防复发的方法。
Dopamine fluctuations in alcoholism
A study suggests that brain dopamine levels in alcohol-dependent individuals increase during periods of abstinence. The cycle of intoxication and withdrawal that characterizes chronic alcoholism induces changes in the brain’s reward pathway, which relies on the neurotransmitter dopamine. Natalie Hirth and colleagues investigated changes in dopamine regulation that occur in alcohol-dependent individuals during periods of abstinence. The authors compared ligand binding by three different dopamine-binding molecules in postmortem human brain tissue samples of heavy alcohol drinkers with samples from those who drank little. Binding to the D2-like receptor was similar in heavy and light drinkers, but ligand binding to the D1 receptor and dopamine transporter was reduced in heavy drinkers. The results indicate a hyperdopaminergic state, marked by high levels of dopamine, associated with alcoholism. The authors showed similar effects in a rat model of alcoholism. Immediately after withdrawal from alcohol, brain tissue samples from the rats indicated low levels of dopamine, but dopamine level indicators increased during periods of abstinence. The increased dopamine levels were associated with hyperactivity and enhanced alcohol seeking in the rats. The authors suggest that brain dopamine levels decrease during the immediate withdrawal from alcohol and later increase to a hyperdopaminergic state during extended abstinence. Uncovering behaviors associated with increased dopamine levels could help identify ways to prevent relapse, according to the authors.
论文 “Convergent evidence from alcohol dependent humans and rats for hyperdopaminergic state in protracted abstinence,” 作者Natalie Hirth 等人
www.psychspace.com心理学空间网
