Many animals taste and smell their environment with the same part of their body, but could it be the same for humans? New research suggests that this could be the case and that we have olfactory receptors in our tongues.
Animal world
Unlike humans and other mammals, not all animals have noses with odor receptors, but this does not mean they do not have a sense of smell.
For example, crabs capture scents through sensory bristles on their antennae, while snakes, although they have nostrils, actually smell better through their mouths, “fishing” for smells with their forked tongues.
However, smell and taste generally work together to allow animals to navigate the world. This is obvious in snails , for example, whose lower tentacles allow them to smell and taste their environment.
Taste and smell also function as complementary senses in humans. The olfactory cells of the nostrils and the taste buds of the tongue interact in the brain to create a complete picture of what, for example, a person is preparing to eat or drink.
However, until now, researchers have tended to believe that the senses of taste and smell operate individually in humans and other mammals.
First, a study published by Current Biology in 2018 found that when scientists removed the taste cortex from the brains of rats, this affected not only the animals’ ability to perceive taste but also their sense of smell.
This led a new team of scientists to investigate whether mammals, including humans, could also smell with their tongues.
Taste cells can taste and smell
In the new work, the results of which appear in the journal Chemical Senses , the scientists used genetic and biochemical techniques to determine whether the mouse’s taste buds might respond to odor molecules. They then tested laboratory cultures of human cells of fungiform papillae (we recall that there are four types of papillae: fungiform papillae, foliate papillae, filiform papillae and goblet or girdle papillae).
First, they discovered that mouse taste buds actually contained olfactory receptors and that the same was true of cultured human taste cells.
Following this, the team used a scientific technique called calcium imaging to assess how cultured taste cells responded to odor molecules, revealing that taste cells interacted with them in much the same way as normal odor receptor cells. .
Then additional experiments also showed, for the first time, that a taste cell can contain receptors for both smell and taste. This discovery could help shed new light on how taste and smell combine to alert us to the appropriateness of a particular food, for example.
“The presence of olfactory receptors and taste receptors in the same cell will provide us with interesting opportunities to study the interactions between smell and taste stimuli on the tongue,” explains Mehmet Hakan Ozdener, leader of the work.
“Our research may help explain how odor molecules modulate taste perception, something that may lead to the development of odor-based taste modifiers that can help combat excess salt, sugar, and fat in associated intake. diet-related diseases such as obesity and diabetes, “says Hakan.
In the future, researchers hope to discover whether only certain taste cells contain odor receptors and to what extent the odor molecules that taste cells capture can change the way an individual perceives specific tastes.
Referencia: Retronasal Odor Perception Requires Taste Cortex, but Orthonasal Does Not. Meredith L. Blankenship, Maria Grigorova, Donald B. Katz, Joost X. Maier. Current Biology Published:December 20, 2018 DOI:https://doi.org/10.1016/j.cub.2018.11.011 // Mammalian Taste Cells Express Functional Olfactory Receptors . Bilal Malik Nadia Elkaddi Jumanah Turkistani Andrew I Spielman Mehmet Hakan Ozdener . Chemical Senses, 24 April 2019, DOI: https://doi.org/10.1093/chemse/bjz019
