VOA标准英语2010年-Acupuncture Triggers Natural Painkille

Finding could lead to more effective, longer-lasting pain treatment

Faith Lapidus | Washington, DC 07 June 2010 
 Researchers are closer to unlocking the mysteries of acupuncture¹, learning more about why the ancient Chinese needle treatment eases pain.

Scientists have taken another important step toward understanding how acupuncture — the ancient Chinese form of needle therapy — actually eases pain. The technique has been used as a medical treatment for thousands of years, but Western medicine has been slow to adopt the practice, in part because no one could explain how it worked.

One theory was that sticking needles into certain points on the body stimulated² the central nervous system to release natural pain-killing endorphins in the brain. But Dr. Maiken Nedergaard, a neuroscientist at the University of Rochester Medical Center in New York, saw a problem with that explanation.

"If you have pain in the leg or in the arm, you give acupuncture close to where you have the pain," she explains. "So, a central mechanism³ can't explain that, because [then it] wouldn't matter where you give the acupuncture. So we felt there had to be a local mechanism and that's why we looked into adenosine."

Prodding⁴ a natural anesthetic⁵ into action

Adenosine is a natural pain killer⁶ in our cells, which works like a local anesthetic. It's released after an injury, and inhibits⁷ nerve signals so the brain never receives the painful messages. Nedergaard explains that an acupuncture needle starts that process.

"In these cells — the muscle cell and the skin cell — they contain adenosine, but normally they don't release it.  But the needle...you can look at it as a small injury. It's not really painful, but still injures many cells," says Nedergaard. "As soon as adenosine is released it is very potent⁸, so even if a few cells are damaged, it would give rise to a fairly substantial amount of adenosine release and reduction of pain."

Acupuncture's effectiveness as a painkiller⁹ has sometimes been attributed to the placebo¹⁰ effect; patients with chronic¹¹ pain expect the procedure to work, and so they feel better after a treatment, even if their pain is not actually lessened¹².

Nedergaard and her team worked with mice, who, she points out, have no expectations, so their data has not been compromised by the placebo effect. The mice had discomfort¹³ in one paw. The researchers measured the level of pain before and after an acupuncture treatment by touching¹⁴ the paw with a filament¹⁵ and measuring the difference in reaction time.

Nedergaard says understanding the biological basis of acupuncture's effects can lead to improved results.

"Chronic pain is a big issue for patients. We don't have very good painkillers¹⁶ for a very large number of patients and they very often get acupuncture treatment," she says. "So, knowing that adenosine is at least one of the mediators of the painkilling¹⁷ effect of acupuncture, you can go in and simply slow the removal of adenosine and thereby¹⁸ the painkilling effect of acupuncture would last longer."

More than three times longer, Nedergaard found. She says participants at the Purines 2010 scientific meeting in Barcelona, where she presented her team's results, were excited about the findings.

"I think for the field itself, it is very easy to accept because the different steps in the [adenosine] pathway have all been described before. It's always been known that small injury gives rise (to) adenosine release, and it's also been known that adenosine is a painkiller. We just put it together that acupuncture is also injury and you get adenosine release."

Nedergaard is also excited because the drug they used to slow the removal of adenosine — a cancer medication called deoxycoformycin — is already approved by the U.S. government, so human trials may begin soon.
 

1 acupuncture   

n.针灸，针刺法，针疗法

参考例句：

• Written records show that acupuncture dates back to the Song Dynasty.文字记载表明，宋朝就已经有了针灸。
• It's known that acupuncture originated in China.众所周知，针灸起源于中国。

2 stimulated   

a.刺激的

参考例句：

• The exhibition has stimulated interest in her work. 展览增进了人们对她作品的兴趣。
• The award has stimulated her into working still harder. 奖金促使她更加努力地工作。

3 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

4 prodding   

v.刺，戳( prod的现在分词 )；刺激；促使；（用手指或尖物）戳

参考例句：

• He needed no prodding. 他不用督促。
• The boy is prodding the animal with a needle. 那男孩正用一根针刺那动物。 来自《现代英汉综合大词典》

5 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。

6 killer   

n.杀人者，杀人犯，杀手，屠杀者

参考例句：

• Heart attacks have become Britain's No.1 killer disease.心脏病已成为英国的头号致命疾病。
• The bulk of the evidence points to him as her killer.大量证据证明是他杀死她的。

7 inhibits   

阻止，抑制( inhibit的第三人称单数 )； 使拘束，使尴尬

参考例句：

• A small manufacturing sector inhibits growth in the economy. 制造业规模太小有碍经济增长。
• His bad English inhibits him from speaking freely. 他英语学得不好，这使他不能表达自如。

8 potent   

adj.强有力的，有权势的；有效力的

参考例句：

• The medicine had a potent effect on your disease.这药物对你的病疗效很大。
• We must account of his potent influence.我们必须考虑他的强有力的影响。

9 painkiller   

n.止痛药

参考例句：

• I shall persuade him to take the painkiller.我将说服他把药吃下去。
• The painkiller only provides him a short respite from his pain.止痛药仅仅让他在疼痛中有短暂的疏解。

10 placebo   

n.安慰剂；宽慰话

参考例句：

• The placebo has been found to work with a lot of different cases.人们已发现安慰剂能在很多不同的病例中发挥作用。
• The placebo effect refers to all the observable behaviors caused by placebo.安慰剂效应是指由安慰剂所引起的可观察的行为。

11 chronic   

adj.(疾病)长期未愈的，慢性的；极坏的

参考例句：

• Famine differs from chronic malnutrition.饥荒不同于慢性营养不良。
• Chronic poisoning may lead to death from inanition.慢性中毒也可能由虚弱导致死亡。

12 lessened   

减少的，减弱的

参考例句：

• Listening to the speech through an interpreter lessened its impact somewhat. 演讲辞通过翻译的嘴说出来，多少削弱了演讲的力量。
• The flight to suburbia lessened the number of middle-class families living within the city. 随着迁往郊外的风行，住在城内的中产家庭减少了。

13 discomfort   

n.不舒服，不安，难过，困难，不方便

参考例句：

• One has to bear a little discomfort while travelling.旅行中总要忍受一点不便。
• She turned red with discomfort when the teacher spoke.老师讲话时她不好意思地红着脸。

14 touching   

adj.动人的，使人感伤的

参考例句：

• It was a touching sight.这是一幅动人的景象。
• His letter was touching.他的信很感人。

15 filament   

n.细丝；长丝；灯丝

参考例句：

• The source of electrons in an electron microscope is a heated filament.电子显微镜中的电子源，是一加热的灯丝。
• The lack of air in the bulb prevents the filament from burning up.灯泡内缺乏空气就使灯丝不致烧掉。

16 painkillers   

n.止痛药( painkiller的名词复数 )

参考例句：

• The doctor gave him some painkillers to ease the pain. 医生给了他一些止疼片以减缓疼痛。 来自辞典例句
• The primary painkillers - opiates, like OxyContin - are widely feared, misunderstood and underused. 人们对主要的镇痛药——如鸦片剂奥施康定——存在广泛的恐惧、误解，因此没有充分利用。 来自时文部分

17 painkilling   

[医]止痛的

参考例句：

• Painkilling drugs were not enough to relieve her suffering. 止痛药不能缓解她的痛苦。 来自互联网
• The effect of the painkilling drug didn't wear off for several hours. 止痛药的药效好几个锺头之仍未消失。 来自互联网

18 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。