WIKIMEDIA, HELENA PAFFENThe detection of chemical odors isn’t limited to the nose. Internal tissues, including the heart, liver, and gut, are also known to harbor olfactory receptors. “Only a tiny little amount of odorants are used by our receptors in the nose,” chemist Peter Schieberle of the Technical University of Munich told Discovery News. “Odor might have secondary functions in the human body.”
This week (July 7), a team described its research on the olfactory responses of the skin. Hanns Hatt of Ruhr University Bochum in Germany and colleagues examined the response of epidermal cells known as keratinocytes, which express an olfactory receptor called OR2AT4, along with at least four others. The researchers found that Sandalore, a synthetic sandalwood oil used in aromatherapy, perfumes, and skin care products all bound to the receptor, triggering cells to divide and migrate, processes characteristic of skin healing.
Specifically, cell proliferation increased by 32 percent and cell migration by nearly 50 percent when cultured keratinocytes were exposed to high concentrations Sandalore—1,000 times greater than is needed to activated olfactory receptors in the nose—for five days. Another synthetic sandalwood scent, called Brahmanol, had a similar effect, while other versions, including the natural compound, had none. The researchers published their results in Journal of Investigative Dermatology.
(Another study, published in the Archives of Biochemistry and Biophysics last week, also explored the effects of sandalwood oil on skin, finding that the compound caused pre-cancerous keratinocytes to undergo autophagy and cell death. The role of olfactory receptors was not explored.)
In total, more than 150 olfactory receptors have been identified outside the nose and are currently an active area of study. “There is a big trend towards odor receptors being found elsewhere in the body doing other jobs,” Joel Mainland of the Monell Chemical Senses Center in Philadelphia told New Scientist.