23
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Kokumi Substances, Enhancers of Basic Tastes, Induce Responses in Calcium-Sensing Receptor Expressing Taste Cells

      research-article
      * , , ,
      PLoS ONE
      Public Library of Science

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Recently, we reported that calcium-sensing receptor (CaSR) is a receptor for kokumi substances, which enhance the intensities of salty, sweet and umami tastes. Furthermore, we found that several γ-glutamyl peptides, which are CaSR agonists, are kokumi substances. In this study, we elucidated the receptor cells for kokumi substances, and their physiological properties. For this purpose, we used Calcium Green-1 loaded mouse taste cells in lingual tissue slices and confocal microscopy. Kokumi substances, applied focally around taste pores, induced an increase in the intracellular Ca 2+ concentration ([Ca 2+] i) in a subset of taste cells. These responses were inhibited by pretreatment with the CaSR inhibitor, NPS2143. However, the kokumi substance-induced responses did not require extracellular Ca 2+. CaSR-expressing taste cells are a different subset of cells from the T1R3-expressing umami or sweet taste receptor cells. These observations indicate that CaSR-expressing taste cells are the primary detectors of kokumi substances, and that they are an independent population from the influenced basic taste receptor cells, at least in the case of sweet and umami.

          Related collections

          Most cited references51

          • Record: found
          • Abstract: found
          • Article: not found

          Cloning and characterization of an extracellular Ca(2+)-sensing receptor from bovine parathyroid.

          Maintenance of a stable internal environment within complex organisms requires specialized cells that sense changes in the extracellular concentration of specific ions (such as Ca2+). Although the molecular nature of such ion sensors is unknown, parathyroid cells possess a cell surface Ca(2+)-sensing mechanism that also recognizes trivalent and polyvalent cations (such as neomycin) and couples by changes in phosphoinositide turnover and cytosolic Ca2+ to regulation of parathyroid hormone secretion. The latter restores normocalcaemia by acting on kidney and bone. We now report the cloning of complementary DNA encoding an extracellular Ca(2+)-sensing receptor from bovine parathyroid with pharmacological and functional properties nearly identical to those of the native receptor. The novel approximately 120K receptor shares limited similarity with the metabotropic glutamate receptors and features a large extracellular domain, containing clusters of acidic amino-acid residues possibly involved in calcium binding, coupled to a seven-membrane-spanning domain like those in the G-protein-coupled receptor superfamily.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Human receptors for sweet and umami taste.

            The three members of the T1R class of taste-specific G protein-coupled receptors have been hypothesized to function in combination as heterodimeric sweet taste receptors. Here we show that human T1R2/T1R3 recognizes diverse natural and synthetic sweeteners. In contrast, human T1R1/T1R3 responds to the umami taste stimulus l-glutamate, and this response is enhanced by 5'-ribonucleotides, a hallmark of umami taste. The ligand specificities of rat T1R2/T1R3 and T1R1/T1R3 correspond to those of their human counterparts. These findings implicate the T1Rs in umami taste and suggest that sweet and umami taste receptors share a common subunit.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              An amino-acid taste receptor.

              The sense of taste provides animals with valuable information about the nature and quality of food. Mammals can recognize and respond to a diverse repertoire of chemical entities, including sugars, salts, acids and a wide range of toxic substances. Several amino acids taste sweet or delicious (umami) to humans, and are attractive to rodents and other animals. This is noteworthy because L-amino acids function as the building blocks of proteins, as biosynthetic precursors of many biologically relevant small molecules, and as metabolic fuel. Thus, having a taste pathway dedicated to their detection probably had significant evolutionary implications. Here we identify and characterize a mammalian amino-acid taste receptor. This receptor, T1R1+3, is a heteromer of the taste-specific T1R1 and T1R3 G-protein-coupled receptors. We demonstrate that T1R1 and T1R3 combine to function as a broadly tuned L-amino-acid sensor responding to most of the 20 standard amino acids, but not to their D-enantiomers or other compounds. We also show that sequence differences in T1R receptors within and between species (human and mouse) can significantly influence the selectivity and specificity of taste responses.
                Bookmark

                Author and article information

                Contributors
                Role: Editor
                Journal
                PLoS One
                PLoS ONE
                plos
                plosone
                PLoS ONE
                Public Library of Science (San Francisco, USA )
                1932-6203
                2012
                12 April 2012
                : 7
                : 4
                : e34489
                Affiliations
                [1]Institute for Innovation, Ajinomoto Co., Inc., Kawasaki, Japan
                German Institute for Human Nutrition, Germany
                Author notes

                Conceived and designed the experiments: YM MK YE. Performed the experiments: YM RY. Analyzed the data: YM RY. Contributed reagents/materials/analysis tools: YM RY MK YE. Wrote the paper: YM YE.

                Article
                PONE-D-11-20373
                10.1371/journal.pone.0034489
                3325276
                22511946
                b2ebe8ae-8634-4771-b4ab-4a8bfd2ae589
                Maruyama et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
                History
                : 14 October 2011
                : 1 March 2012
                Page count
                Pages: 8
                Categories
                Research Article
                Biology
                Molecular Cell Biology
                Signal Transduction
                Signaling Pathways
                Calcium-Mediated Signal Transduction
                Membrane Receptor Signaling
                Neuroscience
                Sensory Systems
                Gustatory System
                Medicine
                Anatomy and Physiology
                Neurological System
                Sensory Physiology
                Cell Physiology
                Sensory Systems

                Uncategorized
                Uncategorized

                Comments

                Comment on this article