难治的偏头痛让科学家头痛

The hunt is intensifying for new treatments for migraines, the common and debilitating headaches that have confounded scientists for decades.
人类正在加紧寻求治疗偏头痛的方法，这种让人身体虚弱的常见头痛病已经困扰了科学家数十年。

Of greatest focus for researchers is a brain chemical known as CGRP, which appears to play a role in the transmission of pain, but not in other brain functions, such as cognition or mood. Researchers are trying a variety of experimental drugs to stop CGRP from working by blocking its receptors in the brain. Others are working on artificial antibodies that could soak up the chemical in the bloodstream or brain before it can trigger migraines.
研究人员关注最多的是一种名为降钙素基因相关口（CGRP）的大脑化学物质，这种物质似乎与痛感传递有关，但是在认知或情绪等大脑的其它功能方面并没有造成影响。研究人员尝试使用各种实验药物，通过屏蔽大脑里感应CGRP的部分来阻止CGRP发生作用。还有一些人正致力于人工抗体的研制，使其在CGRP引发偏头痛之前将血液或大脑中的这种化学物质吸收。

Experts say the need for new medicines to treat migraine pain once it begins is great because current drugs only provide some benefit for 50% to 60% of sufferers and can't be used in people with heart disease or who have had a stroke. Also, they aren't a cure, and in many cases, the headaches tend to come back within 24 hours.
专家说，治疗偏头痛的新药一旦面世就会有巨大需求，因为目前的药物只对大约50%-60%的患者有一定疗效，并且心脏病患者和有中风病史的人都不能服用。而且这些药物并不能治本，在很多病例中，患者在24小时内又会出现头痛。

There also is a separate category of preventive drugs, which tend to be used by a small proportion of people who suffer from more frequent or debilitating migraines.
还有一种单独类型的预防性药物，使用者一般是一小部分偏头痛发生频率较高或发作起来更难受的人。

'People need migraine drugs that have a rapid onset of action, that take the pain away and keep it away,' says Richard Lipton, director of the Montefiore Headache Center in New York.
“人们需要立竿见影的偏头痛药，能够止痛并让它不再复发，”纽约蒙特菲奥里头痛研究中心（Montefiore Headache Center）的主任理查德•利普顿（Richard Lipton）说。

 Headache disorders are among the most common medical conditions world-wide. More than 1 in 10 adults globally are affected by migraines, which can be incapacitating, according to the World Health Organization. International studies have found that 50% to 75% of adults have reported a headache in the past year, with up to 4% of the global population reporting having a headache in half or more of the days each month, WHO says.
头痛症是全世界最常见的医学病症之一。根据世界卫生组织（World Health Organization）的数据，在全球范围内，每10名成年人中就有1人以上身受可能让人无法正常行动的偏头痛之苦。世卫组织说，国际研究发现，在过去的一年里，有50%-75%的成年人声称发生过头痛。全球人口中有4%的人每月有一半或者一半以上的日子里会发生头痛。

There isn't such a thing as a 'regular' headache, but rather more than 300 types, says David Dodick, a professor of neurology at the Mayo Clinic's branch in Phoenix and chairman of the American Migraine Foundation. People having migraines usually experience intense pain, sensitivity to light, dizziness and sometimes nausea and visual and sensory symptoms called auras. Two other major types of headaches are caused by tension or medication overuse.
美国梅约诊所（Mayo Clinic）凤凰城分所神经学教授、美国偏头痛基金会（American Migraine Foundation）主席大卫•多迪克（David Dodick）说，头痛没有一种“常规”病症，而是有300多种类型他也是。患偏头痛的人通常会感受到剧痛、对光线敏感、头晕，有时会感到恶心，还会有一些被称为先兆的视觉和知觉症状。另外两大类头痛的成因是紧张或药物使用过度。

Nonsteroidal anti-inflammatory painkillers such as ibuprofen work for some migraine sufferers. But the class of migraine medicines that hit the market in the 1990s called triptans remain the best or only treatment option for many patients. Nevertheless, about half of sufferers don't respond to them or can't take them because of other health reasons.
像布洛芬这样的非类固醇抗炎镇痛药对某些偏头痛患者有效。但是上世纪90年代面市的曲坦类偏头痛药对很多患者来说仍然是最好或唯一的药物选择。然而，大约一半的患者要么服用这类药后没有效果，要么由于其他健康原因不能服用此类药物。

CGRP, which stands for calcitonin gene-related peptide neurotransmitter, has long been thought to play a role in migraines, but for much of that time for the wrong reason. Part of the confusion was because of a misunderstanding of migraines themselves.
CGRP是降钙素基因相关口神经递质的缩写，长久以来它被认为在偏头痛中发挥了作用，不过很长一段时间里这种看法的依据都是错误的。出现混乱的原因是对偏头痛本身产生了误解。

Why they occur still isn't clear, but specialists say they have recently begun to understand the migraine as a brain disorder and not a vascular disorder. Until about 12 years ago, they were believed to stem from constriction of blood vessels in the brain. The dilation of the vessels to compensate then led to the throbbing pain, so the thinking went.
偏头痛发生的原因尚不清楚，但是专家们说他们最近开始把偏头痛当作一种大脑病症而非血管病症。直到大约12年前，偏头痛都被认为是由于大脑血管收缩引起的。血管的补偿性扩张就导致了搏动痛，当时的人们就是这么想的。

Now, it appears more likely that migraines 'hijack' the brain's normal pain circuitry, says Dr. Dodick. The brain's normal pain-sensory system, in which nerve endings send messages to the brain about a threat, goes awry in migraines.
多迪克说，现在看来，更有可能是偏头痛“拦截”了大脑的正常疼痛回路。在大脑正常的疼痛感知系统里，神经末梢会将威胁信息发送给大脑，偏头痛发生时这个系统就会出错。

Experts disagree about how a migraine is triggered, but the trigeminal nerve - an important pathway that carries sensory information about the face - and its connections to numerous other nerves and the brain appear to be responsible for transmitting the pain.
偏头痛是如何引发的？专家们对此意见不一，但是三叉神经（传递面部周围感官信息的重要途径）以及它与其它各种神经和大脑的连接神经似乎是传递疼痛的介质。