They discovered the exact path by which chili peppers feel “hot” and mints feel “cold” when the signals reach our brains:
The 2021 Nobel Prize for Physiology or Medicine was awarded to David Julius of the University of California, San Francisco, and Ardem Patapoutian of Scripps Research in La Jolla, California, for “for their discoveries of receptors for temperature and touch.”
It’s been a longstanding mystery why chili peppers feel hot to the taste:
“In order to truly appreciate Dr. Julius’ discovery, a bit of context may be in order. Unless you build up tolerance, eating spicy foods is painful. Peppers and wasabi give off a strange sensation that your mouth is on fire, and for the longest time researchers simply couldn’t figure out why this was the case. Failing to pinpoint any immediate benefits of this response, they speculated it must be the remnant of some distant evolutionary adaptation.
“Dr. Julius answered this question by showing us what TRPV1 is responsible for: keeping our bodies safe from high temperatures. The channel responds not only to capsaicin, but also to temperatures that are greater than 110 degrees Fahrenheit. TRPV1 also acts up when we are injured or sunburned, causing damaged tissue to feel hot to the touch. In all cases, the channel transmits a signal that our brains turn into the sensation of heat. – Tim Brinkhof, “Beyond Pain and Pressure: 2021 Nobel Prize for Medicine Awards Work on Sensory Perception” at Big Think (October 7, 2021)”
To track the system at work, researchers needed to catch it responding to a false heat signal created by the receptor for capsaicin, the substance that makes the chili peppers taste painfully hot.
The receptor is an ion channel (a protein) called TRPV1: It “opens when heat is sensed: ”News, “Nobel Prize Medicine win solves a mystery in hot, cold sensing” at Mind Matters News
Takehome: By pinpointing actors and processes precisely, the work of Julius’s and Patapoutian’s teams may help address chronic pain — traditionally hard to resolve.