© iStockphotoLungs.
Your lungs know a bitter sensation when they taste one.
Yes, taste. In a
Nature Medicine study, Stephen B. Liggett and company found receptors on the smooth muscle in the lungs that respond to bitterness, similar to the bitter taste buds on the tongue. And, Liggett found, the receptors' reaction to bitterness is to relax the muscles, and therefore to expand airways. That was totally unexpected, he says, and opens intriguing possibilities for pulmonary treatment - for example,
asthmatic symptoms could be treated by exposing these receptors to bitter compounds.
Like tastebuds on the tongue, the receptors react to bitterness, but unlike tastebuds they do not send any signals to the brain. The researchers thought the taste receptors might have evolved as a protection against toxic plants [Boston Globe]
The researchers first thought that bitter compounds might trigger a constriction of the airways, to prevent toxins from further infiltrating the lungs. The fact that Liggett saw the opposite, airways opening up, suggests that this feature evolved to help us fight off infections like bronchitis or pneumonia, where it would be beneficial to relax the airway so a person could cough up noxious fluids from the lungs.
