时差N小时:失去知觉之后 Out for the Count

If you've ever had major surgery, you probablyremember lying down and waking up-but nothing inbetween.

如果你曾经做过重大手术，那么你肯定只记得躺下去和醒来这么2个动作，而其间过程是浑然不知的。

Thanks to the anesthesiologist, during the actualsurgery you were out of it: immobilized andinsensitive to pain.

多亏了麻醉师，你才能在手术中无知觉地度过：不能动弹，也感觉不到疼痛。

But until recently scientists had little understandingof how anesthetics actually work on the cellular level.

但是直到最近科学家们才多少了解到麻醉药是如何在细胞层面上工作的。

That's changed thanks to recent experiments performed by researchers at the University ofZurich, in Switzerland.

还得感谢瑞士苏黎世大学的研究员们最近做的实验，这一困惑才得以解开。

They knew that anesthetics caused pain receptors in the brain to turn off by acting like mostdrugs do:

他们弄清楚了麻药是通 过关闭大脑中的疼痛接收器才使人感觉不到疼痛，原理跟大多数药物一样：

anesthetizing drugs attach to particular sites on nerve cells and turn them off.

麻药附着在神经细胞上某个特殊位置，然后将感知功能关闭。

The question was, where on nerve cells do these drugs attach?

问题是，麻药到底附着在什么位置呢?

Nerve cell membranes have receptors for different kinds of chemicals produced by the brain.

神经细胞膜有多个接收器来识别大脑产生的不同类别的化学物质。

Gamma-amino butyric acid, or GABA, for example, is a chemical that shuts down nerve cells.

例如γ-氨基丁酸，或者简写为GABA，就是可以关闭神经细胞感知功能的化学物质。

The hypothesis was that general anesthesia works by binding to GABA receptors on a nervecell,thereby activating the receptor and instructing the cell to shut down.

假设全身麻醉是将麻药和在神经细胞上的GABA接收器绑定在一起，从而激活接收器，然后再传达闭接收功能的指令关闭。

So it made sense for the Zurich researchers to focus on GABA receptors.

这样的假设就使苏黎世大学的研究员们明白，集中精力研究GABA接收器是关键所在。

To do this they worked with mice that had been genetically engineered to have nerve cellswith GABA receptors that wouldn't respond to anesthetics.

为了证明这点，他们用基因改造过的老鼠做实验，这种老鼠身上的 GABA接收器对麻药免疫。

And sure enough, when such mice were given anesthetic drugs they weren't nearly asimmune to pain as regular mice that had also been given pain-blocking drugs.

毫无疑问，这样的老鼠在使用了麻药后，比起正常的用了麻药的老鼠，疼痛感几乎没有降低。

Clearly, GABA receptor sites on nerve cells are part of what allows anesthetics to do their job.

显然位于神经细胞上的GABA接收器是让麻药起作用的原因之一。

While the Zurich experiment fills in only one piece of the puzzle, it is an important steptowards learning how these amazing drugs work, and how to make them even better.

尽管苏黎世大学做的实验只解决了一小部分困惑，但是这对于了解这些神奇的药物如何工作的，以及怎样让它们发挥更好的效果是重要的一步。