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.