Olfactory Receptors Identified in Bronchi

Olfactory receptors (ORs), responsible for detecting scent, have been found for the first time in the bronchi, and by their interactions with the receptors, certain substances can cause the bronchi themselves to contract or dilate. A study out of Germany, published last week in Frontiers in Physiology, details the findings and their implications.

The two types of receptors were identified as OR1D2 and OR2AG1, expressed the protein and RNA levels of human airway smooth muscle cells, “ubiquitously present in the bronchial tissue.”

When exposed to amyl butyrate, an ester described as having a “banana apricot” scent, the OR2AG1 receptors are stimulated. When the fresh scent binds with the receptor, the bronchi dilates, allowing for easier breathing and counteracting the effects of histamines. Hans Hatt, one of the researchers, says that the effect of amyl butyrate “can probably counteract not only the effect of histamine, but also that of other allergens that make breathing difficult." These discoveries may be good news for sufferers of asthma, or perhaps even COPD.

The other receptor, OR1D2, reacts in the opposite to certain scents. Bourgeonal, a perfume-ish, floral scent, caused these receptors to retract, causing inflammation and inhibiting breathing. The study suggests that “ORs might be new therapeutic targets for these diseases, and blocking ORs could be an auspicious strategy for the treatment of early-stage chronic inflammatory lung diseases.”

Because the study claims to be the first to identify ORs in bronchial passageways, and observes a few ways in which odorants can impact respiratory reactions, it may provide the basis for new imaginings of asthma and COPD treatment in the future.