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Ecarma MJY, Nolden AA. A review of the flavor profile of metal salts: understanding the complexity of metallic sensation. Chem Senses 2021; 46:6366361. [PMID: 34498058 DOI: 10.1093/chemse/bjab043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The oral sensation of metallic is a complex experience. Much of our current understanding of metallic sensation is from the investigation of metal salts, which elicit diverse sensations, including taste, smell, and chemesthetic sensations, and therefore meet the definition of a flavor rather than a taste. Due to the involvement of multiple chemosensory systems, it can be challenging to define and characterize metallic sensation. Here, we provide a comprehensive review of the psychophysical studies quantifying and characterizing metallic sensation, focusing on metal salts. We examine the factors that impact perception, including anion complex, concentration, nasal occlusion, and pH. In addition, we summarize the receptors thought to be involved in the perception of metallic sensation (i.e., TRPV1, T1R3, TRPA1, and T2R7) either as a result of in vitro assays or from studies in knock-out mice. By enhancing our scientific understanding of metallic sensation and its transduction pathways, it has the potential to improve food and pharmaceuticals, help identify suppression or masking strategies, and improve the ability to characterize individual differences in metallic sensation. It also has the potential to translate to clinical populations by addressing the disparities in knowledge and treatment options for individuals suffering from metallic taste disorder (i.e., phantom taste or "metal mouth"). Future psychophysical studies investigating the sensory perception of metal salts should include a range of compounds and diverse food matrices, coupled with modern sensory methods, which will help to provide a more comprehensive understanding of metallic sensation.
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Affiliation(s)
- Michelle J Y Ecarma
- Department of Food Science, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Alissa A Nolden
- Department of Food Science, University of Massachusetts Amherst, Amherst, MA 01003, USA
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2
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Delay ER, Weaver B, Lane DR, Kondoh T. Dried bonito dashi: Contributions of mineral salts and organic acids to the taste of dashi. Physiol Behav 2019; 199:127-136. [PMID: 30447220 DOI: 10.1016/j.physbeh.2018.11.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 10/18/2018] [Accepted: 11/13/2018] [Indexed: 11/20/2022]
Abstract
Dried bonito dashi is often used in Japanese cuisine with a number of documented positive health effects. Its major taste is thought to be umami, elicited by inosine 5'-monophosphate (IMP) and L-amino acids. Previously we found that lactic acid, a major component of dried bonito dashi, enhanced the contribution of many of these amino acids to the taste of dried bonito dashi, and reduced the contribution of other amino acids. In addition to amino acids, dried bonito dashi also has a significant mineral salt component. The present study used conditioned taste aversion methods with mice (all had compromised olfactory systems) to compare the taste qualities of dried bonito dashi with four salts (NaCl, KCl, CaCl2 and MgCl2), with and without lactic acid or citric acid. A conditioned taste aversion to 25% dried bonitio dashi generalized significantly to NaCl and KCl, with or without 0.9% lactic acid added but not when citric acid was added. Generalization of the CTA to dried bonito dashi was much stronger to the divalent salts, but when either lactic acid or citric acid was added, this aversion was eliminated. These results suggest that these salts contribute to the complex taste of dried bonito dashi and that both organic acids appear able to modify the tastes of divalent salts.
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Affiliation(s)
- Eugene R Delay
- Department of Biology and Vermont Chemical Senses Group, University of Vermont, Burlington, VT 05405, USA.
| | - Benjamin Weaver
- Department of Biology and Vermont Chemical Senses Group, University of Vermont, Burlington, VT 05405, USA
| | - Douglas R Lane
- Department of Biology and Vermont Chemical Senses Group, University of Vermont, Burlington, VT 05405, USA
| | - Takashi Kondoh
- Institute for Innovation, Ajinomoto Co., Inc., 1-1, Suzuki-cho, Kawasaki-ku, Kawasaki 210-8681, Japan
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3
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McCaughey SA. Characterization of mouse chorda tympani responses evoked by stimulation of anterior or posterior fungiform taste papillae. Neurosci Res 2018; 141:43-51. [PMID: 29580888 DOI: 10.1016/j.neures.2018.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 02/18/2018] [Accepted: 03/22/2018] [Indexed: 11/30/2022]
Abstract
Different gustatory papilla types vary in their locations on the tongue. Distinctions have often made between types, but variation within fungiform papillae has seldom been explored. Here, regional differences in fungiform papillae were investigated by flowing solutions selectively over either an anterior fungiform (AF, tongue tip) or a posterior fungiform (PF, middle third) region as taste-evoked activity was measured in the chorda tympani nerve of C57BL/6J (B6) mice. Significantly larger responses were evoked by NaCl applied to the AF than PF region, and the ENaC blocker amiloride reduced the NaCl response size only for the former. Umami synergy, based on co-presenting MSG and IMP, was larger for the AF than PF region. The regions did not differ in response size to sour chemicals, but responses to l-lysine, l-arginine, sucrose, and tetrasodium pyrophosphate were larger for the AF than PF region. Thus, fungiform papillae on the tongue tip differed from those found further back in their transduction mechanisms for salty and umami compounds. Gustatory sensitivity also showed regional variation, albeit with a complex relationship to palatability and taste quality. Overall, the data support a regional organization for the mouse tongue, with different functional zones for the anterior, middle, and posterior thirds.
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Affiliation(s)
- Stuart A McCaughey
- Department of Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States; Center for Medical Education, Ball State University, Muncie, IN, 47306, United States.
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4
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Karunakaran S, Clee SM. Genetics of metabolic syndrome: potential clues from wild-derived inbred mouse strains. Physiol Genomics 2018; 50:35-51. [DOI: 10.1152/physiolgenomics.00059.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The metabolic syndrome (MetS) is a complex constellation of metabolic abnormalities including obesity, abnormal glucose metabolism, dyslipidemia, and elevated blood pressure that together substantially increase risk for cardiovascular disease and Type 2 diabetes. Both genetic and environmental factors contribute to the development of MetS, but this process is still far from understood. Human studies have revealed only part of the underlying basis. Studies in mice offer many strengths that can complement human studies to help elucidate the etiology and pathophysiology of MetS. Here we review the ways mice can contribute to MetS research. In particular, we focus on the information that can be obtained from studies of the inbred strains, with specific focus on the phenotypes of the wild-derived inbred strains. These are newly derived inbred strains that were created from wild-caught mice. They contain substantial genetic variation that is not present in the classical inbred strains, have phenotypes of relevance for MetS, and various mouse strain resources have been created to facilitate the mining of this new genetic variation. Thus studies using wild-derived inbred strains hold great promise for increasing our understanding of MetS.
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Affiliation(s)
- Subashini Karunakaran
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Susanne M. Clee
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
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5
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Abstract
The taste system of animals is used to detect valuable nutrients and harmful compounds in foods. In humans and mice, sweet, bitter, salty, sour and umami tastes are considered the five basic taste qualities. Sweet and umami tastes are mediated by G-protein-coupled receptors, belonging to the T1R (taste receptor type 1) family. This family consists of three members (T1R1, T1R2 and T1R3). They function as sweet or umami taste receptors by forming heterodimeric complexes, T1R1+T1R3 (umami) or T1R2+T1R3 (sweet). Receptors for each of the basic tastes are thought to be expressed exclusively in taste bud cells. Sweet (T1R2+T1R3-expressing) taste cells were thought to be segregated from umami (T1R1+T1R3-expressing) taste cells in taste buds. However, recent studies have revealed that a significant portion of taste cells in mice expressed all T1R subunits and responded to both sweet and umami compounds. This suggests that sweet and umami taste cells may not be segregated. Mice are able to discriminate between sweet and umami tastes, and both tastes contribute to behavioural preferences for sweet or umami compounds. There is growing evidence that T1R3 is also involved in behavioural avoidance of calcium tastes in mice, which implies that there may be a further population of T1R-expressing taste cells that mediate aversion to calcium taste. Therefore the simple view of detection and segregation of sweet and umami tastes by T1R-expressing taste cells, in mice, is now open to re-examination.
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6
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Abstract
Taste is one of the fundamental senses, and it is essential for our ability to ingest nutritious substances and to detect and avoid potentially toxic ones. Taste buds, which are clusters of neuroepithelial receptor cells, are housed in highly organized structures called taste papillae in the oral cavity. Whereas the overall structure of the taste periphery is conserved in almost all vertebrates examined to date, the anatomical, histological, and cell biological, as well as potentially the molecular details of taste buds in the oral cavity are diverse across species and even among individuals. In mammals, several types of gustatory papillae reside on the tongue in highly ordered arrangements, and the patterning and distribution of the mature papillae depend on coordinated molecular events in embryogenesis. In this review, we highlight new findings in the field of taste development, including how taste buds are patterned and how taste cell fate is regulated. We discuss whether a specialized taste bud stem cell population exists and how extrinsic signals can define which cell lineages are generated. We also address the question of whether molecular regulation of taste cell renewal is analogous to that of taste bud development. Finally, we conclude with suggestions for future directions, including the potential influence of the maternal diet and maternal health on the sense of taste in utero.
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Affiliation(s)
- Linda A Barlow
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA; Graduate Program in Cell Biology, Stem Cells and Development, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA; Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA.
| | - Ophir D Klein
- Departments of Orofacial Sciences and Pediatrics, University of California San Francisco, San Francisco, California, USA; Program in Craniofacial and Mesenchymal Biology, University of California San Francisco, San Francisco, California, USA; Institute for Human Genetics, University of California San Francisco, San Francisco, California, USA
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7
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Tordoff MG, Aleman TR, McCaughey SA. Heightened avidity for trisodium pyrophosphate in mice lacking Tas1r3. Chem Senses 2014; 40:53-9. [PMID: 25452580 DOI: 10.1093/chemse/bju059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Laboratory rats and mice prefer some concentrations of tri- and tetrasodium pyrophosphate (Na3HP2O7 and Na4P2O7) to water, but how they detect pyrophosphates is unknown. Here, we assessed whether T1R3 is involved. We found that relative to wild-type littermate controls, Tas1r3 knockout mice had stronger preferences for 5.6-56mM Na3HP2O7 in 2-bottle choice tests, and they licked more 17.8-56mM Na3HP2O7 in brief-access tests. We hypothesize that pyrophosphate taste in the intact mouse involves 2 receptors: T1R3 to produce a hedonically negative signal and an unknown G protein-coupled receptor to produce a hedonically positive signal; in Tas1r3 knockout mice, the hedonically negative signal produced by T1R3 is absent, leading to a heightened avidity for pyrophosphate.
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Affiliation(s)
- Michael G Tordoff
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA and
| | - Tiffany R Aleman
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA and
| | - Stuart A McCaughey
- Center for Medical Education, IUSM-Muncie at Ball State University, 221 N. Celia Avenue, MT 201, Muncie, IN 47306, USA
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8
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Emerging roles of the extracellular calcium-sensing receptor in nutrient sensing: control of taste modulation and intestinal hormone secretion. Br J Nutr 2014; 111 Suppl 1:S16-22. [PMID: 24382107 DOI: 10.1017/s0007114513002250] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The extracellular Ca-sensing receptor (CaSR) is a sensor for a number of key nutrients within the body, including Ca ions (Ca²⁺) and L-amino acids. The CaSR is expressed in a number of specialised cells within the gastrointestinal (GI) tract, and much work has been done to examine CaSR's role as a nutrient sensor in this system. This review article examines two emerging roles for the CaSR within the GI tract--as a mediator of kokumi taste modulation in taste cells and as a regulator of dietary hormone release in response to L-amino acids in the intestine.
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9
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Tordoff MG, Ellis HT. Taste dysfunction in BTBR mice due to a mutation of Itpr3, the inositol triphosphate receptor 3 gene. Physiol Genomics 2013; 45:834-55. [PMID: 23859941 DOI: 10.1152/physiolgenomics.00092.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The BTBR T+ tf/J (BTBR) mouse strain is indifferent to exemplars of sweet, Polycose, umami, bitter, and calcium tastes, which share in common transduction by G protein-coupled receptors (GPCRs). To investigate the genetic basis for this taste dysfunction, we screened 610 BTBR×NZW/LacJ F2 hybrids, identified a potent QTL on chromosome 17, and isolated this in a congenic strain. Mice carrying the BTBR/BTBR haplotype in the 0.8-Mb (21-gene) congenic region were indifferent to sweet, Polycose, umami, bitter, and calcium tastes. To assess the contribution of a likely causative culprit, Itpr3, the inositol triphosphate receptor 3 gene, we produced and tested Itpr3 knockout mice. These were also indifferent to GPCR-mediated taste compounds. Sequencing the BTBR form of Itpr3 revealed a unique 12 bp deletion in Exon 23 (Chr 17: 27238069; Build 37). We conclude that a spontaneous mutation of Itpr3 in a progenitor of the BTBR strain produced a heretofore unrecognized dysfunction of GPCR-mediated taste transduction.
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10
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Abstract
Many animals can detect the taste of calcium but it is unclear how or whether humans have this ability. We show here that calcium activates hTAS1R3-transfected HEK293 cells and that this response is attenuated by lactisole, an inhibitor of hT1R3. Moreover, trained volunteers report that lactisole reduces the calcium intensity of calcium lactate. Thus, humans can detect calcium by taste, T1R3 is a receptor responsible for this, and lactisole can reduce the taste perception of calcium by acting on T1R3.
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11
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Mattes RD. Accumulating evidence supports a taste component for free fatty acids in humans. Physiol Behav 2011; 104:624-31. [PMID: 21557960 PMCID: PMC3139746 DOI: 10.1016/j.physbeh.2011.05.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/13/2011] [Accepted: 05/03/2011] [Indexed: 01/22/2023]
Abstract
The requisite criteria for what constitutes a taste primary have not been established. Recent advances in understanding of the mechanisms and functions of taste have prompted suggestions for an expanded list of unique taste sensations, including fat, or more specifically, free fatty acids (FFA). A set of criteria are proposed here and the data related to FFA are reviewed on each point. It is concluded that the data are moderate to strong that there are: A) adaptive advantages to FFA detection in the oral cavity; B) adequate concentrations of FFA to serve as taste stimuli; C) multiple complimentary putative FFA receptors on taste cells; D) signals generated by FFA that are conveyed by gustatory nerves; E) sensations generated by FFA that can be detected and scaled by psychophysical methods in humans when non-gustatory cues are masked; and F) physiological responses to oral fat/FFA exposure. On no point is there strong evidence challenging these observations. The reviewed findings are suggestive, albeit not definitive, that there is a taste component for FFA.
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Affiliation(s)
- Richard D Mattes
- Department of Foods and Nutrition, Purdue University, 700 W State Street, West Lafayette, IN 47907-2059, USA.
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12
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Cherukuri CM, McCaughey SA, Tordoff MG. Comparison of differences between PWD/PhJ and C57BL/6J mice in calcium solution preferences and chorda tympani nerve responses. Physiol Behav 2011; 102:496-502. [PMID: 21219921 DOI: 10.1016/j.physbeh.2010.12.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 12/23/2010] [Indexed: 10/18/2022]
Abstract
We used the C57BL/6J (B6) and PWD/PhJ (PWD) mouse strains to investigate the controls of calcium intake. Relative to the B6 strain, the PWD strain had higher preferences in two-bottle choice tests for CaCl(2), calcium lactate (CaLa), MgCl(2), citric acid and quinine hydrochloride, but not for sucrose, KCl or NaCl. We also measured taste-evoked chorda tympani (CT) nerve activity in response to oral application of these compounds. Electrophysiological results paralleled the preference test results, with larger responses in PWD than in B6 mice for those compounds that were more highly preferred for the former strain. The strain differences were especially large for tonic, rather than phasic, chorda tympani activity. These data establish the PWD strain as a "calcium-preferring" strain and suggest that differences between B6 and PWD mice in taste transduction or a related peripheral event contributes to the differences between the strains in preferences for calcium solutions.
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Affiliation(s)
- Chandra M Cherukuri
- Department of Physiology and Health Science, Ball State University, Muncie, IN 47306, USA
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13
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Curley JP, Mashoodh R. Parent-of-origin and trans-generational germline influences on behavioral development: the interacting roles of mothers, fathers, and grandparents. Dev Psychobiol 2010; 52:312-30. [PMID: 20373326 DOI: 10.1002/dev.20430] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mothers and fathers do not contribute equally to the development of their offspring. In addition to the differential investment of mothers versus fathers in the rearing of offspring, there are also a number of germline factors that are transmitted unequally from one parent or the other that contribute significantly to offspring development. This article shall review four major sources of such parent-of-origin effects. Firstly, there is increasing evidence that genes inherited on the sex chromosomes including the nonpseudoautosomal part of the Y chromosome that is only inherited from fathers to sons, contribute to brain development and behavior independently of the organizing effects of sex hormones. Secondly, recent work has demonstrated that mitochondrial DNA that is primarily inherited only from mothers may play a much greater than anticipated role in neurobehavioral development. Thirdly, there exists a class of genes known as imprinted genes that are epigenetically silenced when passed on in a parent-of-origin specific manner and have been shown to regulate brain development and a variety of behaviors. Finally, there is converging evidence from several disciplines that environmental variations experienced by mothers and fathers may lead to plasticity in the development and behavior of offspring and that this phenotypic inheritance can be solely transmitted through the germline. Mechanistically, this may be achieved through altered programming within germ cells of the epigenetic status of particular genes such as retrotransposons and imprinted genes or potentially through altered expression of RNAs within gametes.
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Affiliation(s)
- J P Curley
- Department of Psychology, Columbia University, Room 406, Schermerhorn Hall, 1190 Amsterdam Avenue, New York, NY 10027, USA.
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14
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Abstract
There has been extensive work to elucidate the behavioral and physiological mechanisms responsible for taste preferences of the rat but little attempt to delineate the underlying genetic architecture. Here, we exploit the FHH-Chr n(BN)/Mcwi consomic rat strain set to identify chromosomes carrying genes responsible for taste preferences. We screened the parental Fawn Hooded Hypertensive (FHH) and Brown Norway (BN) strains and 22 FHH-Chr n(BN) consomic strains, with 96-h 2-bottle tests, involving a choice between water and each of the following 16 solutions: 10 mM NaCl, 237 mM NaCl, 32 mM CaCl(2), 1 mM saccharin, 100 mM NH(4)Cl, 32 mM sucrose, 100 mM KCl, 4% ethanol, 1 mM HCl, 10 mM monosodium glutamate, 1 mM citric acid, 32 microM quinine hydrochloride, 1% corn oil, 32 microM denatonium, 1% Polycose, and 1 microM capsaicin. Depending on the taste solution involved, between 1 and 16 chromosomes were implicated in the response. Few of these chromosomes carried genes believed to mediate taste transduction in the mouse, and many chromosomes with no candidate taste genes were revealed. The genetic architecture of taste preferences is considerably more complex than has heretofore been acknowledged.
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Affiliation(s)
- Michael G Tordoff
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA.
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15
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Bystrova MF, Romanov RA, Rogachevskaja OA, Churbanov GD, Kolesnikov SS. Functional expression of the extracellular-Ca2+-sensing receptor in mouse taste cells. J Cell Sci 2010; 123:972-82. [PMID: 20179105 DOI: 10.1242/jcs.061879] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Three types of morphologically and functionally distinct taste cells operate in the mammalian taste bud. We demonstrate here the expression of two G-protein-coupled receptors from the family C, CASR and GPRC6A, in the taste tissue and identify transcripts for both receptors in type I cells, no transcripts in type II cells and only CASR transcripts in type III cells, by using the SMART-PCR RNA amplification method at the level of individual taste cells. Type I taste cells responded to calcimimetic NPS R-568, a stereoselective CASR probe, with Ca(2+) transients, whereas type I and type II cells were not specifically responsive. Consistent with these findings, certain amino acids stimulated PLC-dependent Ca(2+) signaling in type III cells, but not in type I and type II cells, showing the following order of efficacies: Phe~Glu>Arg. Thus, CASR is coupled to Ca(2+) mobilization solely in type III cells. CASR was cloned from the circumvallate papilla into a pIRES2-EGFP plasmid and heterologously expressed in HEK-293 cells. The transfection with CASR enabled HEK-293 cells to generate Ca(2+) transients in response to the amino acids, of which, Phe was most potent. This observation and some other facts favor CASR as the predominant receptor subtype endowing type III cells with the ability to detect amino acids. Altogether, our results indicate that type III cells can serve a novel chemosensory function by expressing the polymodal receptor CASR. A role for CASR and GPRC6A in physiology of taste cells of the type I remains to be unveiled.
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Affiliation(s)
- Marina F Bystrova
- Institute of Cell Biophysics, Russian Academy of Sciences, Institutional Street 3, Pushchino, Moscow Region, 142290, Russia
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16
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Reed DR, Knaapila A. Genetics of taste and smell: poisons and pleasures. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 94:213-40. [PMID: 21036327 PMCID: PMC3342754 DOI: 10.1016/b978-0-12-375003-7.00008-x] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Eating is dangerous. While food contains nutrients and calories that animals need to produce heat and energy, it may also contain harmful parasites, bacteria, or chemicals. To guide food selection, the senses of taste and smell have evolved to alert us to the bitter taste of poisons and the sour taste and off-putting smell of spoiled foods. These sensory systems help people and animals to eat defensively, and they provide the brake that helps them avoid ingesting foods that are harmful. But choices about which foods to eat are motivated by more than avoiding the bad; they are also motivated by seeking the good, such as fat and sugar. However, just as not everyone is equally capable of sensing toxins in food, not everyone is equally enthusiastic about consuming high-fat, high-sugar foods. Genetic studies in humans and experimental animals strongly suggest that the liking of sugar and fat is influenced by genotype; likewise, the abilities to detect bitterness and the malodors of rotting food are highly variable among individuals. Understanding the exact genes and genetic differences that affect food intake may provide important clues in obesity treatment by allowing caregivers to tailor dietary recommendations to the chemosensory landscape of each person.
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Ohsu T, Amino Y, Nagasaki H, Yamanaka T, Takeshita S, Hatanaka T, Maruyama Y, Miyamura N, Eto Y. Involvement of the calcium-sensing receptor in human taste perception. J Biol Chem 2009; 285:1016-22. [PMID: 19892707 DOI: 10.1074/jbc.m109.029165] [Citation(s) in RCA: 196] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
By human sensory analyses, we found that various extracellular calcium-sensing receptor (CaSR) agonists enhance sweet, salty, and umami tastes, although they have no taste themselves. These characteristics are known as "kokumi taste" and often appear in traditional Japanese cuisine. Although GSH is a typical kokumi taste substance (taste enhancer), its mode of action is poorly understood. Here, we demonstrate how the kokumi taste is enhanced by the CaSR, a close relative of the class C G-protein-coupled receptors T1R1, T1R2, and T1R3 (sweet and umami receptors). We identified a large number of CaSR agonist gamma-glutamyl peptides, including GSH (gamma-Glu-Cys-Gly) and gamma-Glu-Val-Gly, and showed that these peptides elicit the kokumi taste. Further analyses revealed that some known CaSR agonists such as Ca(2+), protamine, polylysine, L-histidine, and cinacalcet (a calcium-mimetic drug) also elicit the kokumi taste and that the CaSR-specific antagonist, NPS-2143, significantly suppresses the kokumi taste. This is the first report indicating a distinct function of the CaSR in human taste perception.
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Affiliation(s)
- Takeaki Ohsu
- Pharmaceutical Research Laboratories, Ajinomoto Company, Incorporated, Kawasaki 210-8681, Japan
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18
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Abstract
In the U.S. and Europe, most people do not consume the recommended amounts of either calcium or vegetables. We investigated whether there might be a connection; specifically, whether the taste of calcium in vegetables contributes to their bitterness and thus acceptability. We found a strong correlation between the calcium content of 24 vegetables, based on USDA Nutrient Database values, and bitterness, based on the average ratings of 35 people (r = 0.93). Correlations between the content of other nutrients and bitterness were lower and most were not statistically significant. To assess whether it is feasible that humans can detect calcium in vegetables we tested two animal models known to display a calcium appetite. Previous work indicates that calcium solutions are preferentially ingested by PWK/PhJ mice relative to C57BL/6J mice, and by rats deprived of dietary calcium relative to replete controls. In choice tests between collard greens, a high-calcium vegetable, and cabbage, a low-calcium vegetable, the calcium-favoring animals had higher preferences for collard greens than did controls. These observations raise the possibility that the taste of calcium contributes to the bitterness and thus acceptability of vegetables.
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Affiliation(s)
- Michael G Tordoff
- Monell Chemical Senses Center, 3500 Market St., Philadelphia, PA 19104, USA.
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19
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San Gabriel A, Uneyama H, Maekawa T, Torii K. The calcium-sensing receptor in taste tissue. Biochem Biophys Res Commun 2008; 378:414-8. [PMID: 19056349 DOI: 10.1016/j.bbrc.2008.11.060] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Accepted: 11/08/2008] [Indexed: 10/21/2022]
Abstract
Calcium is an essential nutrient that induces a distinctive taste quality, but the sensing mechanism of calcium in the tongue is poorly understood. A recent study linked calcium to T1R3 receptor. Here, we propose another system for calcium taste involving the extracellular calcium-sensing receptor (CaSR). This G protein-coupled receptor that responds to calcium and magnesium cations is involved in calcium homeostasis regulating parathyroid and kidney functions. In this study, CaSR was found in isolated taste buds from rats and mice. It was expressed in a subset of cells in circumvallate and foliate papillae, with fewer cells in the fungiform papillae. This is the first evidence in mammals that locates CaSR in gustatory tissue and provides the basis for better understanding not only calcium taste but also the taste of multiple CaSR agonists.
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Affiliation(s)
- Ana San Gabriel
- Institute of Life Sciences, Ajinomoto Co. Inc., Suzuki-cho 1-1, Kawasaki-ku, Kawasaki 210-8681, Japan
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Tordoff MG. Gene discovery and the genetic basis of calcium consumption. Physiol Behav 2008; 94:649-59. [PMID: 18499198 PMCID: PMC2574908 DOI: 10.1016/j.physbeh.2008.04.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Accepted: 04/02/2008] [Indexed: 10/22/2022]
Abstract
This review makes the case that gene discovery is a worthwhile approach to the study of ingestive behavior in general and to calcium appetite in particular. A description of the methods used to discover genes is provided for non-geneticists. Areas covered include the characterization of an appropriate phenotype, the choice of suitable mouse strains, the generation of a hybrid cross, interval mapping, congenic strain production, and candidate gene analysis. The approach is illustrated with an example involving mice of the C57BL/6J and PWK/PhJ strains, which differ in avidity for calcium solutions. The variation between the strains can be attributed to at least seven quantitative trait loci (QTLs). One of these QTLs is most likely accounted for by Tas1r3, which is a gene involved in the detection of sweet and umami tastes. The discovery of a novel function for a gene with no previously known role in calcium consumption illustrates the power of gene discovery methods to uncover novel mechanisms.
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Affiliation(s)
- Michael G Tordoff
- Monell Chemical Senses Center, 3500 Market St., Philadelphia, PA 19104, USA.
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Tordoff MG, Shao H, Alarcón LK, Margolskee RF, Mosinger B, Bachmanov AA, Reed DR, McCaughey S. Involvement of T1R3 in calcium-magnesium taste. Physiol Genomics 2008; 34:338-48. [PMID: 18593862 DOI: 10.1152/physiolgenomics.90200.2008] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Calcium and magnesium are essential for survival but it is unknown how animals detect and consume enough of these minerals to meet their needs. To investigate this, we exploited the PWK/PhJ (PWK) strain of mice, which, in contrast to the C57BL/6J (B6) and other inbred strains, displays strong preferences for calcium solutions. We found that the PWK strain also has strong preferences for MgCl2 and saccharin solutions but not representative salty, sour, bitter, or umami taste compounds. A genome scan of B6 x PWK F2 mice linked a component of the strain difference in calcium and magnesium preference to distal chromosome 4. The taste receptor gene, Tas1r3, was implicated by studies with 129.B6ByJ-Tas1r3 congenic and Tas1r3 knockout mice. Most notably, calcium and magnesium solutions that were avoided by wild-type B6 mice were preferred (relative to water) by B6 mice null for the Tas1r3 gene. Oral calcium elicited less electrophysiological activity in the chorda tympani nerve of Tas1r3 knockout than wild-type mice. Comparison of the sequence of Tas1r3 with calcium and saccharin preferences in inbred mouse strains found 1) an inverse correlation between calcium and saccharin preference scores across primarily domesticus strains, which was associated with an I60T substitution in T1R3, and 2) a V689A substitution in T1R3 that was unique to the PWK strain and thus may be responsible for its strong calcium and magnesium preference. Our results imply that, in addition to its established roles in the detection of sweet and umami compounds, T1R3 functions as a gustatory calcium-magnesium receptor.
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Affiliation(s)
- Michael G Tordoff
- Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104-3308, USA.
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