There is no shortage of people who love spicy food. Often referred to as chili-heads, these gastromasochists seek out the burn that comes from a hot pepper’s capsaicin. Indeed, some hot sauces enjoy a dedicated and zealous fanbase.
But there’s a fine line between pleasure and pain. And that line is called TRPV1. This protein is laced into the nerve fibers on the skin and tongue and responds to both temperature to toxins. When you bite into a cayenne pepper or touch a too-hot teapot, TRPV1 is the thing that tells you “ouch.”
David Julius began hunting for TRPV1 close to 20 years ago. At the time, scientists had for decades been using capsaicin, the molecule that gives chili peppers their heat, to study pain. But little was known about how it triggered that sensation. Other scientists had already tried and failed to find the molecule that binds to capsaicin, known as its receptor, but that only enticed Julius to take on the challenge. “People had looked for it for many years, and it took on a mythical glow,” said Julius, a biologist at the University of California, San Francisco. “What is this elusive thing?”
A better understanding of this sophisticated mechanism could lead to new painkillers which dampen TRPV1’s sensitivity. The medications could be a welcome alternative to opioides, which are effective but have some unfortunate side-effects.
And there are some upsides to pain; without the "ouch," we might just keep eating hot peppers higher and higher on the Scoville scale: