Take a deep breath. Taste anything? Actually, your lungs may.
Because scientists have discovered that the same receptors that
exist on the tongue to taste bitter substances are also found
on the smooth muscle of the lungs.
Researchers were studying the receptors on smooth lung muscles
that regulate contraction and relaxation of the airways. That's
when they made the discovery-which was so unexpected that the
researchers themselves were skeptical.
Finally, they became convinced that the receptors were really
there, though not clustered in taste buds as they are on the
tongue. The scientists then exposed human and mouse airways to
various bitter compounds to gauge the effects.
Many toxic compounds are bitter, so the researchers expected
the lung muscle to tense up and contract-to compel the breather
to move away from whatever was bitter and perhaps toxic. But,
in a second surprise, bitter compounds relaxed and opened airways
better than any existing asthma drug. The study is in the journal
Nature Medicine. [Deepak Deshpande et al., "Bitter taste receptors
on airway smooth muscle bronchodilate by localized calcium signaling
and reverse obstruction"]
Researchers will continue to search for the role of the receptors.
Meanwhile, the work represents a surprising new lead in the search
for drugs to treat asthma, emphysema or chronic bronchitis.