Researchers Identify Gene Linked to Heroin Relapse
The threat of relapse hangs over any attempt to kick a heroin addiction. The results of a new study provide new clues as to which drug users may be at greater risk of sabotaging their treatment efforts. Scientists have identified a gene that plays a crucial role in controlling heroin craving and relapse behavior in rodents.
The nucleus accumbens is a brain region important for processing pleasure and rewards; as such, it is central to heroin addiction. Using the drug activates the area, which is divided into a core and a shell, to produce effects that are both pleasurable and highly addictive. Ivan Diamond of the Ernest Gallo Clinic and Research Center in Emeryville, Calif., and his colleagues studied rats that ingested repeated doses of heroin and found that a gene known as AGS3 can increase the output of the signaling in some neurons that respond to the drug. When the researchers inhibited the expression of AGS3 in the nucleus accumbens core of animals that had previously experienced both addiction and withdrawal, they found that the rats showed less desire to seek out additional drugs after they were given a small dose. Interfering AGS3 expression in the shell of the nucleus accumbens did not dampen their desire for the drug, however.
The results build on work that previously implicated AGS3 in cocaine relapse as well. "These observations," the authors conclude, "open an avenue to develop treatments for heroin addiction directed against relapse." A report detailing the findings will be published online this week by the Proceedings of the National Academy of Sciences. --Sarah Graham
据sciam5月31日报道，长久以来人们一直尝试着防止吸毒者药物戒毒后复吸。科学家已经在啮齿类动物体内鉴别出一个在控制海洛因成瘾和复吸行为上起着关键性作用的基因。对于将海洛因作为药物来使用的患者来说，更高的成瘾危险性可能会影响其治疗效果。美国最新的研究结果为这种情况提供了种新的解决方案。
阿肯伯氏核（nucleus accumbens）位于大脑的中心区域负责处理快乐和奖赏等行为，对海洛因的成瘾也起着关键的作用。该区域分为核区和外壳区，药物激活该区域后产生快乐和很高的上瘾性作用。美国加利福尼亚州Emeryville的Ernest Gallo临床和研究中心的Ivan Diamond及其同事研究了重复给海洛因后的老鼠，发现在一些与药物应答相关的神经区中，名为“AGS3”的基因输出的信号增加了。当研究者抑制了那些上瘾后停止服药的小鼠脑部阿肯伯氏核区AGS3的表达，发现它们对于药物的成瘾性减少了。但是，如果抑制阿肯伯氏核外壳区AGS3的表达，对药物的成瘾性将不起作用。
此项研究结果是基于以前发现的AGS3基因对咖啡因成瘾作用研究之上的。研究者表示此项研究的详细结果将于近期发表在英国《自然》杂志的电子版上，该项研究为开发海洛因戒瘾后复吸的治疗提供了新的研究方法。
