ATP is Pinned Down as Taste Neurotransmitter

Adenosine 5'-triphosphate (ATP) has been identified as the key neurotransmitter that passes chemical information from the taste buds to gustatory nerve fibers, a process that enables the sense of taste (Science 2005, 310, 1495). Neurotransmitters responsible for taste signal transduction had not been fully elucidated before now, although previous studies suggested that serotonin (5-hydroxytryptamine, 5-HT) might be the key chemical messenger. To test that hypothesis, Thomas E. Finger and Sue C. Kinnamon at the Rocky Mountain Taste & Smell Center and at Colorado State University and their colleagues examined the tasting ability of mice lacking a 5-HT receptor subunit. That the mice could still taste normally indicates that serotonin doesn't act on the receptors to transmit taste information. The team subsequently found that mice lacking two ATP receptor subunits had a greatly reduced ability to discern sweeteners, monosodium glutamate, and bitter substances. As a final piece of evidence, the researchers detected the release of ATP from taste buds when they were stimulated in vitro.