研究发现抑郁症可以检测

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Researchers may have found test for depression
\"This test could serve to predict the efficacy of antidepressant therapy quickly, within four to five days, sparing patients the agony of waiting a month or more to find out if they are on the correct therapeutic regimen,\" said Mark Rasenick, UIC distinguished university professor of physiology and biophysics and psychiatry.

Despite decades of research, the biological basis of depression is unknown, and the molecular and cellular targets of antidepressant treatment remain elusive, although it is likely that these drugs have one or more primary targets.

Rasenick said the discovery could help millions who suffer from undiagnosed depression or receive unsuccessful treatment.

\"We discovered that in depressed individuals a signaling protein is located in specific areas of the cell membrane called lipid rafts,\" he said. This protein, called Gs alpha, activates adenylyl cyclase, a link in signal transduction, and is responsible for the action of neurotransmitters such as serotonin.

\"These 'rafts' are thick, viscous, almost gluey areas, that either facilitate or impede communication between membrane molecules,\" Rasenick said. \"When Gs alpha is caught in these lipid raft domains, its ability to couple with and activate adenylyl cyclase is markedly reduced. Antidepressants help to move the Gs alpha out of these rafts and facilitate the action of certain neurotransmitters.\"

Previous research in both rats and cultured brain cells by Rasenick and his colleagues, as well as others, has shown that Gs alpha changed its location in response to antidepressants, moving out of the lipid rafts to areas of the membrane that allow more efficient communication among membrane components responsible for neurotransmitter action. Further, antidepressant and antipsychotic drugs have been shown to concentrate in these lipid rafts.

\"This new study shows that in depressed humans, Gs alpha protein is confined in lipid rafts, where it's less likely to mediate the action of neurotransmitters, and that antidepressants have the opposite effect,\" Rasenick said.

\"In simple language -- we may be able to tell you if you are depressed and more importantly, whether you are responding to the chosen antidepressant therapy.\"

The new study may also explain why antidepressants take so long to work and why chemically dissimilar compounds have similar effects.

In their study, Rasenick and colleagues compared brain samples from depressed people who had committed suicide with controls who had no history of psychiatric disorders. They found that while the total amount of Gs alpha was the same in the depressed and non-depressed, the depressed have a greater proportion of Gs alpha confined to lipid rafts. The localization of other G proteins was not different.

Rasenick and his colleagues have begun further studies to confirm and expand these findings.

http://www.physorg.com/news124478051.html
研究发现抑郁症可以检测
伊利诺斯大学（芝加哥）医学院的研究者发现，大脑内蛋白质位置的改变可以作为抑郁症的生物标记，因此可以用一种简单、快捷的试验室测试来确定患者是否患有抑郁症，进而决定是否采取对策给予特定的抗抑郁治疗。该项研究发表在3月份第12期的《神经科学杂志》上。
伊利诺斯大学（UIC）生理学、生物物理学和精神病学知名教授Mark Rasenick说， “该项研究有助于在4~5天内快速预测抗抑郁治疗的效果，使患者免受等待一个月甚至更长时间来评判治疗方案正确与否的痛苦。”
尽管研究了数十年，抑郁症生物学机理依然未知，抗抑郁药物治疗的分子和细胞靶点仍然捉摸不透，但这些药物很可能有一个或多个主要靶点。Rasenick说，“该发现为成千上万未确诊为抑郁症的或者接受不成功治疗的人带来了福音。我们发现在抑郁人群中，一种信号蛋白位于细胞膜上被称为脂质筏的特定区域。”这种被称为Gsa的蛋白能够激活信号转导途径中的腺苷酸环化酶，并且负责神经递质如5-羟色胺的活动。Rasenick说，“这些脂质筏厚而且粘，几乎呈胶体状，膜分子间的联系要么更加容易要么被阻断。当Gsa蛋白进入这些脂质筏区域，其结合和激活腺苷酸环化酶的能力大大减弱。而抗抑郁药物有助于驱走这些脂质筏中的Gsa，从而使特定递质的活动更加容易。和其他人的研究一样，Rasenick和他的同事早期进行的大鼠和培养的脑细胞研究结果也表明Gsa通过改变位置对抗抑郁药物作出反应，从脂质筏中移至膜区从而使对递质活动作出响应的膜组分间的联系更加有效。进一步的研究发现，抗抑郁和抗精神病药物都对脂质筏有浓缩作用。Rasenick说，“新的研究结果显示，抑郁病人中的Gsa蛋白限定在脂质筏中，在那里不大可能调节递质的活动，并且抗抑郁药物有相反的结果。简言之——我们可以告诉你是否患上抑郁症，更重要的是，你是否对抗抑郁治疗有所反应。”
新的研究还可以解释为什么抗抑郁药物要花很长时间去治疗以及为什么化学结构不同的化合物有相同的治疗效果。在该研究中，Rasenick和他的同事还比较了自杀的抑郁症患者和没有精神病史的对照人群的大脑样品。他们发现，Gsa的总量是相同的，只是抑郁病人限定在脂质筏区域的Gsa更多。其它G蛋白的定位则没有区别。Rasenick和他的同事又开始了进一步确证及拓展研究。