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Monday, November 8, 2010

Taste buds in the lungs

In a finding that surprised even them, researchers lead by Stephen Liggett from the University of Maryland detected bitter taste receptors in human lungs. Yes, that's right. Our lungs have taste buds in them. This discovery may lead to advances in asthma treatment.

The taste buds were revealed serendipitously during an investigation into how the smooth muscle airways in lungs contract during asthma attacks. Lungs contain muscle receptors that regulate airway contraction. Apparently, they also contain taste receptors.

This is a slide of lung taste receptors through a microscope. Red bands are receptors, blue dots are nuclei.

Credit: University of Maryland School of Medicine.

At first, the scientists assumed that the receptors in the lungs would cause airways to constrict upon contact with bitter inhalants. They reasoned that the lung taste buds would cause people to flee from noxious chemicals. However, the opposite proved true. Stimulating the lungs with bitter substances caused the airways to relax, and to a remarkable degree.

According to Liggett:

[The bitter compounds] all opened the airway more profoundly than any known drug that we have for treatment of asthma or chronic obstructive pulmonary disease (COPD).

Obviously, this opens up new possibilities for treating asthma and other lung diseases. The substances must be aerosolized and breathed, not ingested, which is perhaps for the best since they’re bitter. Although the taste buds in the lungs are identical to the ones found in the mouth, the lung taste buds do not send taste signals to the brain.