title: A TAS1R receptor-based explanation of sweet 'water-taste'.
abstract: 'Water-tastes' are gustatory after-impressions elicited by water following the removal of a chemical solution from the mouth, akin to colour after-images appearing on 'white' paper after fixation on coloured images. Unlike colour after-images, gustatory after-effects are poorly understood. One theory posits that 'water-tastes' are adaptation phenomena, in which adaptation to one taste solution causes the water presented subsequently to act as a taste stimulus. An alternative hypothesis is that removal of the stimulus upon rinsing generates a receptor-based, positive, off-response in taste-receptor cells, ultimately inducing a gustatory perception. Here we show that a sweet 'water-taste' is elicited when sweet-taste inhibitors are rinsed away. Responses of cultured cells expressing the human sweetener receptor directly parallel the psychophysical responses-water rinses remove the inhibitor from the heteromeric sweetener receptor TAS1R2-TAS1R3, which activates cells and results in the perception of strong sweetness from pure water. This 'rebound' activity occurs when equilibrium forces on the two-state allosteric sweet receptors result in their coordinated shift to the activated state upon being released from inhibition by rinsing.
authors.affiliation: Monell Chemical Senses Center, 3500 Market Street, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Veronica
authors.initials: V
authors.lastname: Galindo-Cuspinera
authors.forename: Marcel
authors.initials: M
authors.lastname: Winnig
authors.forename: Bernd
authors.initials: B
authors.lastname: Bufe
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Meyerhof
authors.forename: Paul A S
authors.initials: PA
authors.lastname: Breslin
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology; D000494:Allosteric Regulation / Q000187:drug effects; D006801:Humans; D008954:Models, Biological; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012439:Saccharin / Q000494:pharmacology; D013649:Taste / Q000187:drug effects* / Q000502:physiology*; D014867:Water / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D018094:Receptors, Metabotropic Glutamate; D014867:Water; D012439:Saccharin