WEBVTT - How Does Aspirin Work?

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<v Speaker 1>Welcome to brain stuff from how stuff works. Hey, brain

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<v Speaker 1>stuff is Christian saga. Here. There are lots of ways

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<v Speaker 1>to numb yourself to the minor aches and pains that

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<v Speaker 1>we humans accrue in our daily lives. But today we're

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<v Speaker 1>talking about aspirin. Why aspirin because although aspirin as we

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<v Speaker 1>know it has only existed since the late eighteen hundreds,

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<v Speaker 1>the plant that it was originally derived from, willow, is

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<v Speaker 1>probably the oldest known pain killer in history. Records of

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<v Speaker 1>people using willow leaves to relieve pain and fevers stretch

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<v Speaker 1>back six thousand years to ancient Assyria and sumer Willow

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<v Speaker 1>was also put to use in ancient Egypt, Babylon, and China,

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<v Speaker 1>and Hippocrates thought it was pretty rad especially for pain

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<v Speaker 1>during childbirth. In the seventeen and eighteen hundreds, scientists were

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<v Speaker 1>on identifying, extracting, and purifying the active ingredient in willow,

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<v Speaker 1>which turned out to be a chemical they called salison,

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<v Speaker 1>which they further discovered your digestive system changes into salacilic acid,

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<v Speaker 1>which is what reacts with stuff in your body to

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<v Speaker 1>relieve pain, reduced fever, and swelling. More on how all

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<v Speaker 1>that works in a second, but first salacilic acid. It

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<v Speaker 1>was a pharmacological superstar. German chemists figured out how to

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<v Speaker 1>synthesize it on an industrial scale in the eighteen seventies,

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<v Speaker 1>effectively ending millennia of willow powder use. But it had

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<v Speaker 1>its drawbacks. Lots of patients couldn't stomach it. Literally, it

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<v Speaker 1>was really hard on the stomach lining The son of

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<v Speaker 1>one such patient, a chemist with Friedrich Bear in Company

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<v Speaker 1>by the name of Felix Hoffman, thought it might be

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<v Speaker 1>less irritating if it was less acidic, so Hoffman converted

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<v Speaker 1>it to what Bayer in Company dubbed aspirin in eighteen

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<v Speaker 1>ninety nine. Aspirin has become the popular and less ridiculous

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<v Speaker 1>to pronounce name for Hoffman's chemical compound, a setal silic

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<v Speaker 1>acid or salicylate. It works, as humanity finally figured out

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<v Speaker 1>in the nineteen seventies, by preventing yourselves from using cyclo

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<v Speaker 1>oxygen ase to to create prostaglandins. And don't worry, I'm

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<v Speaker 1>about to unpack all of those words. Let's start with

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<v Speaker 1>the idea that lots of pain is useful evolutionarily speaking,

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<v Speaker 1>when you feel pain due to an injury like a burn,

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<v Speaker 1>or a twisted ankle. It prompts you to take your

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<v Speaker 1>hand away from that hot thing real quick, or to

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<v Speaker 1>keep your weight off the ankle until it heals. It's

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<v Speaker 1>it's useful, right. Pain from an injury to anything but

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<v Speaker 1>the nervous system is called non susceptive pain after specialized

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<v Speaker 1>sense areene neurons located throughout your body called NA susceptors.

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<v Speaker 1>They alert your brain to damage with the help of

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<v Speaker 1>the damaged tissue itself. Cells in the hurt areas start

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<v Speaker 1>producing enzymes that work together to create a few signal chemicals,

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<v Speaker 1>including those prostaglandins I mentioned a minute ago. Prostaglandins tell

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<v Speaker 1>your NO susceptors, no, hey, seriously, there is a problem here.

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<v Speaker 1>They make your NO susceptors increase the signal to your brain.

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<v Speaker 1>You feel the pain more acutely now. Prostaglandins are also

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<v Speaker 1>one of the chemicals that cause inflammation in the tissue

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<v Speaker 1>around a wound. They make your blood vessels expand, flooding

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<v Speaker 1>the damaged tissue with all the immune systems stuff your

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<v Speaker 1>body sends to protect the wound from infection and to

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<v Speaker 1>help it to heal. All of this is great right

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<v Speaker 1>up until it isn't. After a certain point, you don't

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<v Speaker 1>need continual acute pain as a reminder that you're injured.

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<v Speaker 1>We know, and some non susceptive pain and swelling is

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<v Speaker 1>warning us about stimuli that we can't easily avoid, like headaches, arthritis,

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<v Speaker 1>or period cramps. In the case of arthritis, that inflammation

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<v Speaker 1>can even cause more damage in the long run. Here's

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<v Speaker 1>where aspirin swoops in to save the day. When you

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<v Speaker 1>take aspirin, it's absorbed by your digestive tract into your

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<v Speaker 1>blood stream, which takes it throughout your body, including places

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<v Speaker 1>where cells are excreting the enzymes necessary to produce prostaglandins.

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<v Speaker 1>Molecules of aspirin lock up with one of those enzymes,

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<v Speaker 1>cyclo oxygenase two. Once a molecule of cyclo oxygenase two

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<v Speaker 1>is locked into a molecule of aspirin, it can't help

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<v Speaker 1>create prostaglandins, which means fewer prostaglandins, which means that the

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<v Speaker 1>pain signals to your brain don't increase as much and

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<v Speaker 1>the tissue in the area doesn't swell as much. Hey,

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<v Speaker 1>thanks thousands of years of science. Check out the Brainstuff

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<v Speaker 1>channel on YouTube and for more on this, and thousands

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<v Speaker 1>of other topics. Visit how stuff works dot com.