Scientists Have Discovered an Entirely New Taste Cell—And It Could Be Used to Make Food More Delicious

Scientists have identified a new type of taste cell in mice that, unlike others, can respond to a range of stimuli: bitter, sweet and umami.

A co-author of the study told Newsweek broadening our understanding of how taste works could help make food more delicious, as well as treating humans with certain health problems.

There are three types of taste cells in taste buds. Type I, which help out other cells; Type II, which pick up bitter, sweet and umami flavors; and Type III, which detect sour and salty tastes.

The authors of the paper published in the journal PLOS Genetics found a new subset of "very broadly tuned" Type III cells in mice that respond to bitter, sweet, umami and sour flavors, but not salt, co-author Kathryn Medler, associate professor of biological sciences at the University at Buffalo, told Newsweek. There were called "broadly responsive" taste cells in the study.

Medler said: "It's surprising that we have individual taste cells that can respond to so many different kinds of taste stimuli. It's also a mystery why salt is excluded."

To conduct their study, scientists isolated the taste cells from the tongues of genetically engineered mice. Taste cells are located in the taste buds that dot the surface of the tongue. The team also identified where proteins are expressed in taste cells, and studied mouse brains to analyze how cells in a part of the brain called the solitary tract are activated. The solitary tract is the first area of the brain that detects information on taste.

The researchers also compared how mice behaved when the broadly responsive cells weren't functioning. They trained regular mice and others that were genetically engineered so their broadly responsive cells didn't work to drink water.

Mice whose broadly responsive taste cells weren't working acted like they couldn't taste the stimuli. They approached bad-tasting bitter water like it was normal water, unlike the regular mice. And unlike the non-engineered mice who drank sugar water "like crazy," the tweaked mice drank the same amount as they would if it were tasteless, said Medler. They did the same for umami.

"Thus, we think the broadly responsive taste cells are required for the appropriate signal to be sent to the brain, just like the specific taste cells for bitter, sweet and umami," said Medler.

Medler said our understanding of how information is sent to the brain is "quite limited and a source of disagreement within the field."

Some believe there are only specific cells for each stimulus. Others think the information gets to the brain when cells are activated in a specific pattern across the population to generate each response.

"Our data suggests that it is likely a combination of these two ideas, some taste cells are very specific to the stimuli they respond to while these taste cells are very broadly responsive and can detect a wide range of stimuli," she said.

Acknowledging the limitations of the study, Medler said the team used a bitter compound for their experiments, and did not use a wide array of stimuli. " There may be some differences for other taste stimuli that we haven't identified," she said.

The team also did not determine if the broadly responsive cells and the selective cells work together inside the buds to create a single signal that stimulates the nerve connected to the mouth, or if they are stimulating nerves in the tongue in parallel and that information is integrated at the first synapse in the brain. More research is needed to explore this, said Medler.

She said: "We need to better understand how the taste system works in order to effectively address health issues that cause taste deficits. If we lose our sense of taste, it has a negative effect on appetite and people tend to not eat enough and can become malnourished."

Her team previously used mice to show that obesity caused by diet leads to problems with how taste cells send out signals, which may trigger overeating.

A better understanding of how taste cells normally function would potentially "allow us to make food tastier, or it could allow us to help people taste their food correctly which can impact their health," she said.

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A stock image shows a woman baring her tongue. Scientists have found a new type of taste cell. Getty