[♩INTRO] If you’ve ever had wasabi… Well, actually, you probably haven’t eaten
real wasabi. That’s because it’s super rare outside
of Japan. That green stuff that comes with your sushi is just a blend of horseradish and mustard
dyed to look like wasabi. But if you’ve ever thought you had wasabi, or are just a fan of plain ole horseradish
in general, you’re familiar with that special burning
sensation that fills your nose. Well, that’s thanks to a chemical that’s
abundant in those foods one that triggers your body’s defenses to
toxins. Wasabi and horseradish are both cabbage-type
plants related to things like broccoli, kale, Brussels
sprouts, and mustard. And they’ve been selectively bred for at
least a thousand years to have nice, big rhizomes, a type of underground
stem, because those are ground or shredded to add
that special kick to your meal. The nose burn largely comes from a compound
called allyl isothiocyanate. It’s also found to a lesser extent in mustard
and radishes. It easily becomes airborne, so when you eat
wasabi or horseradish, a bunch of it floats up into your nose, right to where you have all these special
detectors for it. These detectors are called receptors, and
they’re molecules on the surface of nerve cells that allow them to respond
to things. Each type of receptor responds to different
groups of molecules. The one for allyl isothiocyanate is called
TRPA1. And it detects more than wasabi and horseradish. It also alerts your body to the presence of
tear gas, cigarette smoke, and car exhaust. Basically, a bunch of possible airborne irritants. When triggered, receptors tells their nerve
cells to message the brain, which results in that itching or burning sensation. And there are simply more of these receptors
in your nose than in your mouth, which is why you really feel the burn there. Enough of the offensive substance leads to
coughing, crying, basically anything to try and get it out of
you. TRPA1 is related to other pain-causing receptors,
like TRPV1 the one responsible for the burn of hot chilis. But it’s kind of weird because it responds
to a lot of things. In addition to wasabi and airborne irritants,
it can also be set off by chemicals produced by your own cells, so
it’s sometimes to blame for pain, itching, or burning associated with inflammation
or immunological diseases. And it even seems to be involved in sensing
dangerously cold things. It has so many triggers that scientists are
still trying to figure out all the ways it can go off, and how the body uses it. But in the meantime, some are harnessing its
powers for good. A group of researchers is hoping to develop
a special fire alarm for the hard of hearing Instead of making a loud sound, it would spray a mist made of allyl isothiocyanate. It’s basically a wasabi alarm! Because it’s probably better to have the
feeling of fire in your nose than have an actual fire at your feet. Thanks to Jan Bartnik for asking about horseradish! And thanks to all of our patrons who voted
on this question in our poll. We really can’t say it enough: without our
patrons, we couldn’t do what we do. If you have some burning questions like this
that you’d like us to consider, you can learn more about joining our community
of patrons at Patreon.com/SciShow. [♩OUTRO]
