Adenosine triphosphate isn’t an ingredient in eggnog or in the recipe for roast turkey, but it’s key to tasting the drink’s nutmeg and the bird’s gravy.
ATP, as the chemical is known, turns out to relay messages from the tongue to the brain, according to a new study.
“People have been trying to find out for a long time what’s the neurotransmitter for taste,” said Colorado State University biologist Leslie Stone. “We think we have it.”
That answer might surprise basic biology students who know ATP best for its role in making energy for cells.
Scientists recently learned that the chemical also sometimes sends messages between particular types of sensory cells, Stone said.
For moving a message from taste buds to the brain, however, many researchers suspected the chemical courier was serotonin.
Stone and her colleagues proved that suspicion wrong and nailed ATP’s key role in taste in a paper published today in the journal Science.
The researchers found that mice lacking cellular receptors for serotonin could still taste normally, choosing sweetened water over plain and avoiding bitter-tasting liquids, Stone said.
When researchers blocked parts of the animals’ ATP receptors, however, the mice lost the ability to distinguish sweet from bitter.
Stone and her colleagues also demonstrated that taste-bud cells release ATP when stimulated with a strong taste and that the nerve signals generated by ATP’s release traveled into the brain.
Understanding the basic biology of taste is important because it plays such a key role in appetite, said Diego Restrepo, co-director of the Rocky Mountain Taste and Smell Center at the University of Colorado Health Sciences Center in Denver.
People with certain types of diseases or who are undergoing aggressive treatment such as chemotherapy can struggle with appetite, Restrepo said.
A better understanding of taste could help researchers figure out appropriate treatments, said Restrepo, who did not directly contribute to the newly published research.
“The pharmaceutical industry is also interested in this,” he said, because so many medicines taste bitter.
Blocking bitter tastes from reaching the brain could help researchers design easier-to-swallow pills, Restrepo said.
The new findings also could help researchers clarify the relationship between taste, appetite and body fat, he said.
Staff writer Katy Human can be reached at 303-820-1910 or khuman@denverpost.com.
