Your Skin Can Smell

Sort of.

It wasn't until the 1980s and 1990s that scientists finally worked out how the sense of smell works, identifying the "olfactory receptors" that lock onto certain organic molecules. In the nose, those receptors are hooked into a network of nerves that transmit the smell message to the brain, triggering the sensation of smelling something.

But "olfactory receptors" might be doing much more:

Over the last decade or so, scientists have discovered that odor receptors are not solely confined to the nose, but found throughout body — in the liver, the heart, the kidneys and even sperm — where they play a pivotal role in a host of physiological functions.

Now, a team of biologists at Ruhr University Bochum in Germany has found that our skin is bristling with olfactory receptors. “More than 15 of the olfactory receptors that exist in the nose are also found in human skin cells,” said the lead researcher, Dr. Hanns Hatt. . . .

The presence of scent receptors outside the nose may seem odd at first, but as Dr. Hatt and others have observed, odor receptors are among the most evolutionarily ancient chemical sensors in the body, capable of detecting a multitude of compounds, not solely those drifting through the air.

“If you think of olfactory receptors as specialized chemical detectors, instead of as receptors in your nose that detect smell, then it makes a lot of sense for them to be in other places,” said Jennifer Pluznick, an assistant professor of physiology at Johns Hopkins University who in 2009 found that olfactory receptors help control metabolic function and regulate blood pressure in the kidneys of mice.

Which is fascinating. What are the olfactory receptors in our skin for, and what do we do with them? They must be doing something, because otherwise we wouldn't have them, but they aren't wired to the nervous system. Do they transmit chemical messages to surrounding skin cells? What sort, and why?

One possibility is that this relates to the immune system and to healing:

exposing one of these receptors (colorfully named OR2AT4) to a synthetic sandalwood odor known as Sandalore sets off a cascade of molecular signals that appears to induce healing in injured tissue. In a series of human tests, skin abrasions healed 30 percent faster in the presence of Sandalore, a finding the scientists think could lead to cosmetic products for aging skin and to new treatments to promote recovery after physical trauma.

I wouldn't get my hopes up yet about healing skin cream, but work on these systems is just getting started, and there may be lots more surprises to come.