It hurts so good.
You probably already know that the "spicy" sensation we get from wasabi is not the same as we get from a chili; hot peppers rely on capsaicin for their heat, while wasabi—which is in the same family as horseradish and mustard—gets its pungent kick from a compound called allyl isothiocyanate.
Scientists are particularly interested in how we process that sensation—namely, through a protein receptor found in nerve cells that's known as TRPA1. The TRPA1 receptor is what causes our eyes to water and our sinuses to burn when we pile too much of the green stuff onto one of our California rolls. (It's also triggered by the presence of capsaicin.) But due to its capacity as an "irritant-detector," it may also help us understand the science of pain—and how to combat it. In addition to intensely spicy things such as wasabi and tear gas, the protein is responsible for our reaction to internal problems such as inflammation and damage to tissue.
Researchers from the University of California, San Francisco recently completed a thorough visual mapping of the protein, using more than 100,000 images obtained through microscopic photography and x-ray crystallography, in hopes of using it to design new painkillers and analgesic drugs that are better able to pinpoint and respond to things that are harmful or uncomfortable to the body. In a statement to accompany the study of the protein—which appears in the new issue of Nature—co-author David Julius, PhD, explains, "We've known that TRPA1 is very important in sensing environmental irritants, inflammatory pain, and itch, and so knowing more about how TRPA1 works is important for understanding basic pain mechanisms." (The team made a short video documenting their process, as seen below.)
Essentially, the three-dimensional map of TRPA1 could assist in designing medications that are able to target the protein and essentially block its effects. Does this mean it could be theoretically possible to create a drug that would be able to stop you from bugging out after putting too much horseradish paste in your Bloody Mary, or from wheezing and crying at exposure to tear gas during the biweekly police riots that you so fondly attend? It could be. But scientists are more concerned with using it for, you know, medical applications.
Another interesting factoid: TRPV1, the receptor that reacts to capsaicin—i.e., the "heat" in chili peppers, can also be triggered by high temperatures, which may be why this sensation of "hotness" is perceived differently than that of wasabi and horseradish.