How Do Pain Relievers Work? - George Zaidan

Translator: Ido Dekkers Reviewer: Ariana Bleau Lugo

翻译人员: Yoshinari Fukuzawa 校对人员: Scarlett Huang

Say you're at the beach, and you get sand in your eyes.

假设你在海滩上，沙子进了眼睛

How do you know the sand is there?

你怎么知道有沙子呢？

You obviously can't see it, but if you are a normal, healthy human,

显然你看不到 但若你是个正常、健康的人

你可以感觉到有沙子

you can feel it,

that sensation of extreme discomfort, also known as pain.

这种极不舒服的感觉叫做「疼痛」

Now, pain makes you do something,

疼痛要你采取行动

in this case, rinse your eyes until the sand is gone.

此例中是要你 冲洗眼睛，直到沙子消失

And how do you know the sand is gone?

你怎么知道沙子不见了？

Exactly. Because there's no more pain.

没错，因为不痛了

There are people who don't feel pain.

有人感觉不到疼痛

Now, that might sound cool, but it's not.

听起来很酷，但其实一点也不酷

If you can't feel pain, you could get hurt, or even hurt yourself

如果感觉不到疼痛 你可能会受伤，甚至可能伤到自己

and never know it.

而完全不知道

Pain is your body's early warning system.

疼痛是你身体的早期预警系统

It protects you from the world around you, and from yourself.

可保护你不受到 周围世界或自己的伤害

随着我们长大，疼痛感测器 会安装在身体的大多数地方

As we grow, we install pain detectors in most areas of our body.

These detectors are specialized nerve cells

这些感测器是特殊的神经细胞

called nociceptors

称为「痛觉感受器」

that stretch from your spinal cord to your skin, your muscles, your joints,

分布在脊髓、皮肤、肌肉、关节

your teeth and some of your internal organs.

牙齿和一些内脏

Just like all nerve cells, they conduct electrical signals,

就像所有的神经细胞 它们传送电信号

sending information from wherever they're located back to your brain.

从它们所在之处传送讯号回大脑

But, unlike other nerve cells,

但是，不像其他神经细胞

nociceptors only fire if something happens that could cause

痛觉感受器在身体可能或正在收到伤害时

才会作用

or is causing damage.

So, gently touch the tip of a needle.

所以，轻摸针尖

You'll feel the metal, and those are your regular nerve cells.

你可以感觉到金属 一般神经细胞给你这种感觉

But you won't feel any pain.

但是你不会感到任何疼痛

Now, the harder you push against the needle,

但你越用力推针尖

the closer you get to the nociceptor threshold.

越接近痛觉感受器的极限值

Push hard enough, and you'll cross that threshold

很用力的话，就会超过极限值

and the nociceptors fire,

痛觉感受器会启动 并告诉身体停止目前的行为

telling your body to stop doing whatever you're doing.

But the pain threshold isn't set in stone.

痛觉感受器的门槛，并非一成不变

Certain chemicals can tune nociceptors, lowering their threshold for pain.

某些化学​​物质可以调节感受器

降低痛觉的阈值

When cells are damaged, they and other nearby cells

细胞受损时，受损细胞及邻近细胞

start producing these tuning chemicals like crazy,

开始疯狂生产这些调节化学物质

lowering the nociceptors' threshold to the point

降低痛觉感受器的门槛，直到

where just touch can cause pain.

连触摸都会疼痛

And this is where over-the-counter painkillers come in.

这时非处方的止痛药 可以大展身手了

Aspirin and ibuprofen

阿斯匹灵和布洛芬

block production of one class of these tuning chemicals,

可阻止一种调节化学物质的生产

called prostaglandins.

称为「前列腺素」

Let's take a look at how they do that.

我们来探讨一下原理

When cells are damaged, they release a chemical called arachidonic acid.

当细胞损伤，会释放一种化学物质 叫做「花生油酸」

有两种酵素 COX-1 和 COX-2

And two enzymes called COX-1 and COX-2

convert this arachidonic acid into prostaglandin H2,

可将花生油酸转换成前列腺素 H 2

which is then converted into a bunch of other chemicals

再将其转换成一系列化学物质 产生一连串效果

that do a bunch of things,

including raise your body temperature, cause inflammation

包括升高体温、引起发炎、

and lower the pain threshold.

降低疼痛阈值

Now, all enzymes have an active site.

所有的酵素有特定的活性部位

That's the place in the enzyme where the reaction happens.

也就酵素反应发生的地方

The active sites of COX-1 and COX-2

COX-1 和 COX-2 的活性部位

fit arachidonic acid very cozily.

非常适合花生油酸

As you can see, there is no room to spare.

正如你看到的，也没有多余的空间

Now, it's in this active site that aspirin and ibuprofen do their work.

阿斯匹灵和布洛芬，就是在这个 活性部位发挥作用

So, they work differently.

它们的工作原理不同： 阿斯匹灵像豪猪的刺

Aspirin acts like a spine from a porcupine.

It enters the active site and then breaks off,

进入活性部位，然后脱落

leaving half of itself in there,

留下一半在那里

totally blocking that channel and making it impossible

完全阻断通道，让花生油酸进不来

for the arachidonic acid to fit.

This permanently deactivates COX-1 and COX-2.

这会永久停用 COX-1 和 COX-2

Ibuprofen, on the other hand,

另一方面，布洛芬

enters the active site,

进入活性部位 但不破坏或改变酵素

but doesn't break apart or change the enzyme.

COX-1 and COX-2 are free to spit it out again,

COX-1 和 COX-2 可把它再吐出来

but for the time that that ibuprofen is in there,

但布洛芬在那里的期间

the enzyme can't bind arachidonic acid, and can't do its normal chemistry.

酵素无法结合花生油酸

因此无法进行正常的化学反应

But how do aspirin and ibuprofen know where the pain is?

阿斯匹灵和布洛芬 怎么知道哪里痛？

Well, they don't.

噢，它們並不知道

Once the drugs are in your bloodstream,

一旦药物进入血液中

they are carried throughout your body,

就会被带往全身

and they go to painful areas just the same as normal ones.

不但会到疼痛部位 也会到正常部位

这就是阿斯匹灵和布洛芬的原理

So that's how aspirin and ibuprofen work.

But there are other dimensions to pain.

还有其他种类的疼痛

Neuropathic pain, for example,

例如神经性疼痛

is pain caused by damage to our nervous system itself;

是神经系统本身受损 所引起的疼痛

there doesn't need to be any sort of outside stimulus.

这种疼痛不需要任何形式的外界刺激

And scientists are discovering that the brain controls

科学家们发现，大脑控制了

how we respond to pain signals.

我们对疼痛信号的反应

For example, how much pain you feel can depend on

例如，疼痛的程度取决于

whether you're paying attention to the pain, or even your mood.

你对疼痛的在意程度 甚至是你的心情

Pain is an area of active research.

疼痛是个活跃的研究领域

If we can understand it better, maybe we can help people manage it better.

如果我们能更了解疼痛 或许我们就更能有效的管理疼痛