英语听力文摘 English Digest 242、麻醉功效

　　Out for the Count
麻醉药是指能使整个机体或机体局部暂时、可逆性失去知觉及痛觉的药物。根据其作用范围可分为全身麻醉药及局部麻醉药，全身麻醉药及局部麻醉药根据其作用特点和给药方式不同，又可分为吸入麻醉药和静脉麻醉药。直到现在，科学家们依然不能确定这些麻醉药物如何工作。美国加利福尼亚大学的麻醉学专家詹姆斯·桑尼尔说：“这仍然是神经科学中的一个谜，我们可以使生物体失去知觉，在昏睡中接受手术，然后恢复生物体的意识，但我们却缺乏充足的证据说明那些药物是如何工作的。”

　　If you've ever had major surgery, you probably remember lying down and waking up--but nothing in between. Learn about anesthetics on this Moment of Science.
If you’ve ever had major surgery, you probably remember lying down and waking up–but nothing in between. Thanks to the anesthesiologist, during the actual surgery you were out of it: immobilized and insensitive to pain. But until recently scientists had little understanding of how anesthetics actually work on the cellular² level.
That’s changed thanks to recent experiments performed by researchers at the University of Zurich, in Switzerland. They knew that anesthetics caused pain receptors in the brain to turn off by acting³ like most drugs do: anesthetizing drugs attach to particular sites on nerve cells and turn them off. The question was, where on nerve cells do these drugs attach?
Nerve cell membranes(细胞膜) have receptors for different kinds of chemicals produced by the brain. Gamma-amino butyric acid(γ-氨基丁酸), or GABA(伽马氨基丁酸), for example, is a chemical that shuts down nerve cells. The hypothesis was that general anesthesia works by binding⁴ to GABA receptors on a nerve cell, thereby⁵ activating⁶ the receptor and instructing the cell to shut down. So it made sense for the Zurich researchers to focus on GABA receptors.
To do this they worked with mice that had been genetically⁷ engineered to have nerve cells with GABA receptors that wouldn’t respond to anesthetics. And sure enough, when such mice were given anesthetic¹ drugs they weren’t nearly as immune to pain as regular mice that had also been given pain-blocking drugs. Clearly, GABA receptor sites on nerve cells are part of what allows anesthetics to do their job.
While the Zurich experiment fills in only one piece of the puzzle, it is an important step towards learning how these amazing drugs work, and how to make them even better.
译文：
如果你曾经动过手术，你可能会记得躺下和醒来这两个动作，但是对中间发生的事情一无所知。多亏了你的麻醉师，在实际的手术过程中你对疼痛全然不知。但直到最近科学家们对麻醉药如何在细胞水平上发挥作用仍然了解甚少。
归功于瑞士苏黎世大学研究人员的最新研究，这种情况得以改变。他们知道正如许多药物那样，麻醉药让大脑里的疼痛受体处于关闭状态。麻醉药依附在神经细胞里的特定区域，并对它们进行麻醉。问题是，这些药物是依附在神经细胞的的哪个部位呢？
神经细胞膜针对大脑产生的各种化学物质都有受体。如γ-氨基丁酸或伽马氨基丁酸，都是可以使神经细胞关闭的化学物质。假设全身麻醉与神经细胞上的伽马氨基丁酸受体有关，那么可以激活受体，指示细胞关闭。因此苏黎世大学研究人员认为应该着重研究伽马氨基丁酸受体。
为了此项研究，研究人员们用经过遗传工程处理后的老鼠做实验，这些老鼠的伽马氨基丁酸受体不会对麻醉药起反应。果然，这些老鼠在注射了麻醉药后并不像正常的老鼠注射了麻醉药那样，对疼痛免疫。显然，在神经细胞上的伽马氨基丁酸受体就是麻醉药发挥作用的地方。
尽管苏黎世大学的实验只解决了谜团中的一小部分，但是研究麻醉药是怎样工作的以及怎样让它们工作的更好仍是非常重要的。
Notes:
(1)Out for the Count 死的, 毁了的
Count me out for the banana split.
别指望我同你一起分享香蕉味。

1 anesthetic   

n.麻醉剂，麻药；adj.麻醉的，失去知觉的

参考例句：

• He was given a general anesthetic.他被全身麻醉。
• He was still under the influence of the anesthetic.他仍处在麻醉状态。

2 cellular   

adj.移动的；细胞的，由细胞组成的

参考例句：

• She has a cellular telephone in her car.她的汽车里有一部无线通讯电话机。
• Many people use cellular materials as sensitive elements in hygrometers.很多人用蜂窝状的材料作为测量温度的传感元件。

3 acting   

n.演戏，行为，假装；adj.代理的，临时的，演出用的

参考例句：

• Ignore her,she's just acting.别理她，她只是假装的。
• During the seventies,her acting career was in eclipse.在七十年代，她的表演生涯黯然失色。

4 binding   

有约束力的，有效的，应遵守的

参考例句：

• The contract was not signed and has no binding force. 合同没有签署因而没有约束力。
• Both sides have agreed that the arbitration will be binding. 双方都赞同仲裁具有约束力。

5 thereby   

adv.因此，从而

参考例句：

• I have never been to that city,,ereby I don't know much about it.我从未去过那座城市，因此对它不怎么熟悉。
• He became a British citizen,thereby gaining the right to vote.他成了英国公民，因而得到了投票权。

6 activating   

活动的，活性的

参考例句：

• "I didn't say we'd got to stop activating the masses! “我并没说就此不发动！ 来自子夜部分
• Presumably both the very small size and activating influence of fluorine atoms contribute to this exception. 这大概是由于氟原子半径小和活性高这两个原因的影响，氟原子对这种例外做出了贡献。

7 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物