The functional olfactory receptors, the sensors that detect odors in the nose, are also present in human taste cells found on the tongue, according to a report by scientists from the Monell Center. The findings suggest that interactions between the sense of smell and taste, the primary components of food flavor, may begin on the tongue and not in the brain, as previously thought.
The senior author of the study and a cell biologist at Monell, Mehmet Hakan Ozdener, MD, MPH, said that their research might aid the explanation of how odor molecules modulate taste perception. Speaking further, he said that the study might lead to the development of odor-based taste modifiers that can help combat the excess salt, sugar, and fat intake connected with diet-related diseases such as diabetes and obesity.
Though several individuals compare flavor with taste, the distinctive flavor of most foods and drinks comes smell than it does from the taste. Taste detects salty, sweet, sour, bitter, and umami (savory) molecules on the tongue and it evolved as a gatekeeper to evaluate the nutrient value and potential toxicity of what humans put in their mouths. Also, smell offers detailed information about the quality of food flavor, for instance; is that banana, licorice, or cherry? The brain combines input from the taste, smell, and other senses to form the multi-modal sensation of flavor.
The research of Ozdener and colleagues which was published online ahead of print in Chemical Senses utilized techniques developed at Monell to maintain living human taste cells in culture. The researchers used genetic and biochemical methods to probe the taste cell cultures and discovered that the human taste cells contain many critical molecules known to be present in olfactory receptors.
Also, they used calcium imaging to show that the cultured taste cells respond to odor molecules like olfactory receptor cells.
In total, the findings offer 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. To support this possibility, other experiments the scientists from Monell did demonstrated that a single taste cell could contain both taste and olfactory receptors.
Ozdener pointed out that the presence of olfactory receptors and taste receptors in the same cell will provide them with exciting opportunities to study interactions between odor and taste stimuli on the tongue.
The next step for the researchers is to determine whether olfactory receptors are preferentially located on a specific taste cell type, including sweet- or salt-detecting cells. There will also be an exploration into how odor molecules modify taste cell responses and, ultimately, human taste perception in another study.