Bitter is sweet for asthma sufferers

Researchers at the University of Maryland have discovered that the lung has similar bitter taste receptors to the tongue — and that this knowledge could help treat conditions such as asthma.

Dr Stephen Liggett says his team found the taste receptors by accident during a previous study into muscle receptors. Unlike those in the tongue, the receptors aren’t in clusters and don’t send taste signals to the brain. (Now that really would have been an aftertaste…)

The team’s original theory was that the taste buds were designed to alert the body when it had mistakenly ingested a bitter poison from a plant, the idea being that this would cause the person to get a tight chest and cough, prompting them to get away from the source of the poison.

However, testing on humans and mice showed the opposite was true: once stimulated the receptors force the airways to the lungs to open up. Indeed, the effect was greater than with existing drugs designed to treat asthma and related diseases.

Among the substances which successfully stimulated the process were quinine, chloroquine and even saccharin (the bitterness being the aftertaste in that case.) But Dr Ligget warns treatment wouldn’t be as simple as sucking on a lemon. Instead he believes the best way to take advantage of the process would be through an aerosol-based inhaler using chemical modifications of bitter compounds.

E Albert Reece, dean of the School of Medicine at which Ligget’s team works, said “These researchers were willing to take chances and ask questions about an unlikely concept. Why are taste receptors in the lungs? What do they do? Can we take advantage of them to devise a new therapy? In the end, their discoveries are in the best tradition of scientific research.”