Scientists find smell receptors in taste cells on the tongue
A new study from the Monell Chemical Senses Center has revealed that the olfactory receptors used to detect odors in the nose are also present in taste receptor cells on the tongue. The discovery indicates that interactions between smell and taste, which were thought to take place in the brain, may actually be initiated on the tongue.
“Our research may help explain how odor molecules modulate taste perception,” said study senior author Dr. Mehmet Hakan Ozdener. “This may lead to the development of odor-based taste modifiers that can help combat the excess salt, sugar, and fat intake associated with diet-related diseases such as obesity and diabetes.”
The flavors that we perceive come more from smell than from taste. Prior to this study, taste and smell were thought to be independent sensory systems that did not interact until their information reached the brain. However, after his son asked him if snakes stick out their tongues so they can smell, Dr. Ozdener decided to challenge this theory.
The researchers used genetic and biochemical methods to analyze living human taste cells in culture. They noticed that the taste cells contained many key molecules known to be present in olfactory receptors. Next, a technique known as calcium imaging revealed that the cultured taste cells respond to odor molecules much in the same way as olfactory receptor cells.
The study results provide the first evidence of functional olfactory receptors in human taste cells. The findings suggest that olfactory receptors actively participate in the taste system by interacting with taste cells on the tongue.
In additional experiments, the team demonstrated that a single taste cell can contain both taste and olfactory receptors. “The presence of olfactory receptors and taste receptors in the same cell will provide us with exciting opportunities to study interactions between odor and taste stimuli on the tongue,” said Dr. Ozdener.
The study is published in the journal Chemical Senses.