ATP is key taste messenger

Adenosine triphosphate (ATP) has outshined serotonin as the most likely key neurotransmitter passing on the sense of taste from taste bud cells to primary afferent gustatory nerve fibers, researchers report in this week's issue of Science.

"It's the first time that we are able to find, at the level of these synapses, a substance that fills all the criteria of a neurotransmitter," co-author Leslie Stone, from Colorado State University in Fort Collins, Co., told The Scientist. "This doesn't rule out the involvement of serotonin or other substances in the taste bud, we just believe they're acting at another level, probably in the crosstalk between cells."

The cellular and molecular mechanisms of how chemical stimuli -- such as sugars, acids, and salts -- are converted into electrical signals are still widely unknown. Taste cells communicate with themselves through chemical and electric synapses, and some also communicate with nerves afferent...