Science Daily reveals the existence of olfactory receptors – the nerves that give us a sense of smell – located on our tongues:
“Our research may help explain how odor molecules modulate taste perception,” said study senior author Mehmet Hakan Ozdener, MD, PhD, MPH, a cell biologist at Monell. “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.”
While many people equate flavor with taste, the distinctive flavor of most foods and drinks comes more from smell than it does from taste.
Ozdener was prompted to challenge this belief when his 12-year-old son asked him if snakes extend their tongues so they can smell.
In the study, published online ahead of print in Chemical Senses, Ozdener and colleagues used methods developed at Monell to maintain living human taste cells in culture. Using genetic and biochemical methods to probe the taste cell cultures, the researchers found that the human taste cells contain many key molecules known to be present in olfactory receptors.
They next used a method known as calcium imaging to show that the cultured taste cells respond to odor molecules in a manner similar to olfactory receptor cells.
Together, the findings provide the first demonstration of functional olfactory receptors in human taste cells, suggesting that olfactory receptors may play a role in the taste system by interacting with taste receptor cells on the tongue. Supporting this possibility, other experiments by the Monell scientists demonstrated that a single taste cell can contain both taste and olfactory receptors.
Scientists still do not know what molecules activate the vast majority of the 400 different types of functional human olfactory receptors.