Can our skin smell?

The skin is the largest sensory organ in the human body. Using the receptors embedded in the skin, we can gauge the temperature of our surroundings, find out whether a surface is rough or smooth and even feel pain. But would you believe us if we told you that the skin also helps us smell?

Our nose is filled with receptors that help us distinguish smells. Called olfactory receptors (OR), there are about 350 different types of OR that we know of. While one type of receptors makeyou aware of the stinking drain, there is another different set which detects the fragrance of an incense stick and helps you feel relaxed. Recent studies have shown the olfactory receptors are also found in our kidneys, the intestine and the prostate gland but these being internal organs determining the role the ORs is rather difficult. Researcher,Dr. Daniela Busseand her colleagues at the Ruhr University Bochum in Germany have found that a certain type of olfactory receptor called OR2AT4 is found in skin cells as well.

Through a serious of experiments, the researchers determined that the OR2AT4 responds to the smell of Sandalore, a commercially available synthetic odour that resembles Sandalwood. Presence of this odour in the environment activates the OR2AT4 receptors, which in turn activate p38 mitogen activated protein kinases (p38 MAPK). The p38 MAPK play a role in cell divisionand cell survival thus leading the researchers to conclude that the smell of sandalwood could be used to stimulate healing.

The researchers further tested this idea by growing some skin cells in the lab and then inducing some scratch injuries. It was found that cells that were exposed to Sandalore for prolonged periods showed 32% more cell division and around 50 % more migration of new cells to the site of injury when compared to cells that were not exposed to Sandalore. Both these factors would contribute to quicker healing of injuries.

While such a finding is likely to pave to a new generation of healing methods and probably even anti-ageing treatments, it also provides some backing to the existing practises of aromatheraphy. However, researchers are wary of extending the results of this study to all and sundry so soon. Receptorsare notorious for being variable in different individuals. So, how your OR respond to a particular aroma is not necessarily the same way in which they would respond in your siblings or your parents or children and treatments might not be effective. So, a lot of work still needs to be done to find out exact modes of treatment using ORs on the skin.

Nevertheless, the study gives you another reason to buy those scented candles and treat yourself to another session of aromatherapy because now you know your skin can smell them too!

The contributors are authors at Coffee Table Science