The paper
D.A. Deshpande et al., “Bitter taste receptors on airway smooth muscle bronchodilate by localized calcium signaling and reverse obstruction,” Nat Med, 16:1299-304, 2010. Free F1000 Evaluation
The finding
Stephen Liggett and colleagues at the University of Maryland School of Medicine set out to identify the G-protein coupled receptors (GPCRs) involved in the contraction of bronchial airway muscles that can lead to asthma. They discovered bitter taste receptors—previously only found on the tongue—on airway smooth muscle (ASM) cells, and showed that their activation causes bronchial relaxation instead.
The surprise
Liggett thought these receptors might protect against inhaled toxic substances. When his lab treated ASM cells with bitter-tasting compounds, such as saccharin or chloroquine, they saw an increase in intracellular calcium concentration—a hallmark of smooth muscle contraction, and thus presumably of bronchoconstriction. “We were thinking we’d found the cause of occupational asthma,” Liggett says. Surprisingly, when they tested the bitter ...
