The Receptors for Mammalian Sweet and Umami Taste

Cell. 2003 Oct 31;115(3):255-66. doi: 10.1016/s0092-8674(03)00844-4.

Abstract

Sweet and umami (the taste of monosodium glutamate) are the main attractive taste modalities in humans. T1Rs are candidate mammalian taste receptors that combine to assemble two heteromeric G-protein-coupled receptor complexes: T1R1+3, an umami sensor, and T1R2+3, a sweet receptor. We now report the behavioral and physiological characterization of T1R1, T1R2, and T1R3 knockout mice. We demonstrate that sweet and umami taste are strictly dependent on T1R-receptors, and show that selective elimination of T1R-subunits differentially abolishes detection and perception of these two taste modalities. To examine the basis of sweet tastant recognition and coding, we engineered animals expressing either the human T1R2-receptor (hT1R2), or a modified opioid-receptor (RASSL) in sweet cells. Expression of hT1R2 in mice generates animals with humanized sweet taste preferences, while expression of RASSL drives strong attraction to a synthetic opiate, demonstrating that sweet cells trigger dedicated behavioral outputs, but their tastant selectivity is determined by the nature of the receptors.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Flavoring Agents / metabolism
  • Flavoring Agents / pharmacology
  • Gene Deletion
  • Humans
  • In Situ Hybridization
  • Mice
  • Mice, Knockout
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Protein Subunits / genetics
  • Protein Subunits / metabolism
  • Receptors, G-Protein-Coupled / genetics
  • Receptors, G-Protein-Coupled / metabolism*
  • Receptors, Opioid, kappa / genetics
  • Receptors, Opioid, kappa / metabolism
  • Sodium Glutamate / metabolism
  • Sodium Glutamate / pharmacology
  • Sucrose / metabolism
  • Sucrose / pharmacology
  • Taste / drug effects
  • Taste / genetics
  • Taste / physiology*
  • Taste Buds / drug effects
  • Taste Buds / metabolism

Substances

  • Flavoring Agents
  • Protein Isoforms
  • Protein Subunits
  • Receptors, G-Protein-Coupled
  • Receptors, Opioid, kappa
  • Ro1 protein, synthetic
  • taste receptors, type 1
  • Sucrose
  • Sodium Glutamate