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你的嗅觉器官遍布全身

You smell with your body, not just your nose

音乐
[music]
问大家这样一个问题
Here’s the question for you.
詹妮弗·普拉兹尼克
你觉得你能闻到多少种气味?
How many different scents do you think you can smell?
或者说能精确辨别多少种气味
And maybe even identify with accuracy.
一百?三百?一千?
One hundred? three hundred? a thousand?
有项研究表明
One study estimates that humans
人类可以探测到一万亿种不同的气味
can detect up to 1 trillion different odors.
一万亿 难以想像
A trillion, it’s hard to imagine.
但是你的鼻子拥有实现它的分子机器
But your nose has a molecular machinery to make it happen.
众多的嗅觉受体 微型气味探测器
Olfactory receptors, tiny scent detectors,
充满了你的鼻子
are packed into your nose.
每一个都在耐心地等着被
Each one patiently waiting to
气味激活
be activated by the odor,
或者说被指定用来探测配体
or ligand that it’s been assigned to detect.
事实证明人类和所有的脊椎动物
It turns out we humans like all vertebrates
都拥有大量的嗅觉受体
have lots of olfactory receptors.
事实上 我们所有的DNA中
In fact more of our DNA is devoted to
编码不同嗅觉受体的基因比
genes for different olfactory receptors
编码别的类型蛋白质的多
than for any other type of protein.
为什么?
Why is that?
嗅觉受体除了帮助我们闻气味
Could olfactory receptors be doing something else
还有别的功能么?
in addition to allowing us to smell?
琳达·巴克和理查德·阿克塞尔
In 1991 Linda Buck and Richard Axel uncovered
在1991年揭示了嗅觉受体的分子识别机制
the molecular identity of olfactory receptors work,
并且最终获得了诺贝尔奖
which ultimately led to a Nobel Prize.
当时我们都认为
At the time we all assumed that
这些受体只存在于鼻子里
these receptors were only found in the nose.
大概过了一年
However about a year or so later,
一篇报道指出不仅鼻子里有嗅觉受体
a report emerged of an olfactory receptor expressed in a tissue
其它组织里也有
other than the nose .
然后类似报道层出不穷
And then another such report emerged and another.
现在我们已经知道这些受体遍布全身
We now know that these receptors are found all over the body,
甚至包括一些你根本想不到的地方
including in some pretty unexpected places.
肌肉 肾脏 肺和血管
In muscle, in kidneys, lungs and blood vessels.
但是它们在这些地方干什么?
But what are they doing there?
我们知道嗅觉受体是鼻子里
Well we know that olfactory receptors act as
灵敏的化学传感器
sensitive chemical sensors in the nose,
它们靠此来实现嗅觉功能
that’s how they mediate our sense of smell.
事实上它们也在人体内很多其它部位
It turns out they also act as sensitive chemical sensors
充当灵敏的化学传感器
in many other parts of the body.
我不是说当你走进厨房时 你的肝脏
Now I’m not saying that your liver can detect the aroma
能探测到清晨咖啡的芳香
of your morning coffee as you walk into the kitchen.
而是说在你喝完清晨咖啡后
Rather after you drink your morning coffee,
你的肝会利用嗅觉受体
your liver might use an olfactory receptor to
用化学方法探测你血液里流动的
chemically detect the change in concentration
化学物质的浓度变化
of a chemical floating through your bloodstream.
身体里很多类型的细胞和组织
Many cell types and tissues in the body use
都利用化学传感器
chemical sensors or chemosensors to
来监测荷尔蒙 代谢物或
keep track of the concentration of
其它分子的浓度
hormones, metabolites and other molecules.
有些化学传感器就是嗅觉受体
And some of these chemosensors are olfactory receptors.
假设你是一个胰腺或肾脏
If you are a pancreas or a kidney and
你需要一个专门的化学传感器
you need a specialized chemical sensor
来监测某个特定的分子
that will allow you to keep track of a specific molecule.
何必多此一举?
Why reinvent the wheel?
在鼻子之外发现嗅觉受体
One of the first examples of an olfactory receptor found
的先例之一是 在人类精子中
outside the nose showed that human sperm
发现了嗅觉受体的存在
express an olfactory receptor.
拥有这种受体的精子可以寻找到
And that sperm with this receptor will seek out
可以作出响应的化学物质 即受体的配体
the chemical that the receptor responds to, the receptor’s ligand.
也就是说精子会游向配体
That is the sperm will swim toward the ligand.
这就得出一个有趣的暗示
This has intriguing implications.
精子是通过”嗅出”配体浓度最高的区域
Are sperm aided in finding the egg by sniffing out
找到卵子的么?
the area with the highest ligand concentration?
我喜欢这个例子 因为它清楚地
I like this example because it clearly demonstrates
证明了嗅觉受体的基本工作
that an olfactory receptor’s primary job
是充当一个化学传感器
is to be a chemical sensor.
但具体功能视情况而定
But depending on the context.
它可以影响你感知气味的方式
It can influence how you perceive a smell,
或是影响精子的运动方向
or in which direction sperm will swim.
事实证明嗅觉受体能做的还有很多
And as it turns out a huge variety of other processes.
嗅觉受体参与了肌肉细胞移动
Olfactory receptors have been implicated in muscle cell migration,
帮助肺去感知吸入的化学物质并做出响应
in helping the lung to sense and respond to inhaled chemicals,
以及创伤愈合
and in wound healing.
同样地 味觉受体曾被认为只存在于舌头
Similarly taste receptors once thought to be found
现已证明全身的细胞
only in the tongue, are now known to be expressed
和组织都有味觉受体的存在
in cells and tissues throughout the body.
更让人惊讶的是
Even more surprisingly,
近期有研究表明 存在于眼睛里的光受体
a recent study found that the light receptors in our eyes
在血管中也发挥作用
also play a role in our blood vessels.
我的实验室致力于研究肾脏中的
In my lab we work on trying to understand the rules
嗅觉受体和味觉受体的作用
of olfactory receptors and taste receptors in the context of the kidney.
肾脏是体内平衡的控制中心
The kidney is a central control center for homeostasis.
我们认为作为体内平衡控制中心
And to us it makes sense that a homeostatic control center
肾脏拥有化学传感器是很合理的
would be a logical place to employ chemical sensors.
我们已经识别出肾脏中很多
We’ve identified a number of different olfactory
不同的嗅觉和味觉受体
and taste receptors in the kidney.
其中的嗅觉受体78号
One of which olfactory receptor 78
会存在于与调节血压息息相关的
is known to be expressed in cells and tissues
细胞和组织中
that are important in the regulation of blood pressure.
当清除老鼠的这种受体后
When this receptor is deleted in mice,
它们的血压会降低
their blood pressure is low.
让人惊讶的是这种受体会对一种
Surprisingly this receptor was found to respond to
叫做短链脂肪酸的化学物质作出响应
chemicals called short chain fatty acids
这种化学物质由肠道中的细菌
that are produced by the bacteria
也就是肠道菌群产生
that reside in your gut, your gut microbiota.
这些化学物质被肠道菌群生产出来后
After being produced by your gut microbiota,
会被你的血液吸收
these chemicals are absorbed into your bloodstream
并和嗅觉受体78号之类的受体相互作用
where they can then interact with receptors like olfactory receptor 78.
这表明肠道菌群中新陈代谢的改变
Meaning that the changes in metabolism of your gut microbiota
可能会影响血压
may influence your blood pressure.
尽管我们已经在肾脏中识别出一些
Although we’ve identified a number of different
不同的嗅觉和味觉受体
olfactory and taste receptors in the kidney,
但我们才刚刚开始梳理它们不同的功能
we’ve only just begun to tease out their different functions
我们还要找出它们响应的化学物质
and to figure out which chemicals each of them responds to.
针对别的器官和组织的类似研究即将开展
Similar investigations lie ahead for many other organs and tissues,
但目前只有很少的受体被研究
only a small minority of receptors has been studied to date.
这是项激动人心的事业
This is exciting stuff.
它将革新我们对五大感知系统之一的
It’s revolutionizing our understanding of the scope
影响范围的理解
of influence for one of the five senses.
而且它可能改变我们对
And it has the potential to change our understanding
人类生理机能的某些方面的看法
of some aspects of human physiology.
虽然才刚开始 但我相信我们已经嗅到了
It’s still early, but I think we’ve picked up on the scent
我们要追随的气味 谢谢
of something we’re following. Thank you.

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视频概述

介绍了人体中的嗅觉受体,除了存在于鼻子里,它们遍布全身,功能各异

听录译者

研究僧

翻译译者

研究僧

审核员

审核员E

视频来源

https://www.youtube.com/watch?v=XIOw62ZlP0I

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