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Arntsen C, Guillemin J, Audette K, Stanley M. Tastant-receptor interactions: insights from the fruit fly. Front Nutr 2024; 11:1394697. [PMID: 38665300 PMCID: PMC11043608 DOI: 10.3389/fnut.2024.1394697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 04/02/2024] [Indexed: 04/28/2024] Open
Abstract
Across species, taste provides important chemical information about potential food sources and the surrounding environment. As details about the chemicals and receptors responsible for gustation are discovered, a complex view of the taste system is emerging with significant contributions from research using the fruit fly, Drosophila melanogaster, as a model organism. In this brief review, we summarize recent advances in Drosophila gustation and their relevance to taste research more broadly. Our goal is to highlight the molecular mechanisms underlying the first step of gustatory circuits: ligand-receptor interactions in primary taste cells. After an introduction to the Drosophila taste system and how it encodes the canonical taste modalities sweet, bitter, and salty, we describe recent insights into the complex nature of carboxylic acid and amino acid detection in the context of sour and umami taste, respectively. Our analysis extends to non-canonical taste modalities including metals, fatty acids, and bacterial components, and highlights unexpected receptors and signaling pathways that have recently been identified in Drosophila taste cells. Comparing the intricate molecular and cellular underpinnings of how ligands are detected in vivo in fruit flies reveals both specific and promiscuous receptor selectivity for taste encoding. Throughout this review, we compare and contextualize these Drosophila findings with mammalian research to not only emphasize the conservation of these chemosensory systems, but to demonstrate the power of this model organism in elucidating the neurobiology of taste and feeding.
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Affiliation(s)
| | | | | | - Molly Stanley
- Department of Biology, University of Vermont, Burlington, VT, United States
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2
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Doyle ME, Premathilake HU, Yao Q, Mazucanti CH, Egan JM. Physiology of the tongue with emphasis on taste transduction. Physiol Rev 2023; 103:1193-1246. [PMID: 36422992 PMCID: PMC9942923 DOI: 10.1152/physrev.00012.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The tongue is a complex multifunctional organ that interacts and senses both interoceptively and exteroceptively. Although it is easily visible to almost all of us, it is relatively understudied and what is in the literature is often contradictory or is not comprehensively reported. The tongue is both a motor and a sensory organ: motor in that it is required for speech and mastication, and sensory in that it receives information to be relayed to the central nervous system pertaining to the safety and quality of the contents of the oral cavity. Additionally, the tongue and its taste apparatus form part of an innate immune surveillance system. For example, loss or alteration in taste perception can be an early indication of infection as became evident during the present global SARS-CoV-2 pandemic. Here, we particularly emphasize the latest updates in the mechanisms of taste perception, taste bud formation and adult taste bud renewal, and the presence and effects of hormones on taste perception, review the understudied lingual immune system with specific reference to SARS-CoV-2, discuss nascent work on tongue microbiome, as well as address the effect of systemic disease on tongue structure and function, especially in relation to taste.
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Affiliation(s)
- Máire E Doyle
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Hasitha U Premathilake
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Qin Yao
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Caio H Mazucanti
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Josephine M Egan
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
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3
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Kondoh T. Enhanced preference for dried bonito dashi by prior experience with dashi and various taste substances in mice. Physiol Behav 2023; 261:114084. [PMID: 36640957 DOI: 10.1016/j.physbeh.2023.114084] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 01/09/2023] [Accepted: 01/09/2023] [Indexed: 01/13/2023]
Abstract
Dried bonito dashi, a complex mixture of sour, bitter, and umami substances as well as over 400 odorants, is the most widely used Japanese fish broth that enhances palatability of various dishes. Recent studies have suggested that prior experience with dried bonito dashi produces strong enhancement of subsequent intake and preference for dried bonito dashi. The present study investigated taste substances in dried bonito dashi that enhance subsequent dashi preference by its prior exposure. Male C57BL/6N mice were initially exposed for 10 days to (1) dried bonito dashi, (2) a chemical mixture of taste substances identified in dried bonito dashi (artificially reconstituted dashi), or (3) individual chemical solutions such as NaCl, monosodium l-glutamate (MSG), inosine 5'-monophosphate (IMP), lactic acid, histidine, and glucose. Intakes of 0.01-100% dried bonito dashi with water were then measured using ascending concentration series of 2-day two-bottle choice tests. Prior exposure to 1-100% dashi enhanced subsequent dashi preference in a concentration-dependent manner and the greatest effects were attained with 10-100% dashi exposure. Exposure to the reconstituted dashi also enhanced subsequent dashi preference. Among individual chemical solutions, 0.1% IMP produced modest enhancement of subsequent dashi preference, but neither NaCl, MSG, histidine, lactic acid, nor glucose did. These results suggest that IMP is at least a key substance that produces experience-based enhancement of dried bonito dashi preference.
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Affiliation(s)
- Takashi Kondoh
- Laboratory of Food Chemistry, Department of Food Science and Nutrition, Faculty of Agriculture, Kindai University, 3327-204, Nakamachi, Nara 631-8505, Japan; AJINOMOTO Integrative Research for Advanced Dieting, Graduate School of Agriculture, Kyoto University, Kitashirakawaoiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan.
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Bioactive and Sensory Di- and Tripeptides Generated during Dry-Curing of Pork Meat. Int J Mol Sci 2023; 24:ijms24021574. [PMID: 36675084 PMCID: PMC9866438 DOI: 10.3390/ijms24021574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Dry-cured pork products, such as dry-cured ham, undergo an extensive proteolysis during manufacturing process which determines the organoleptic properties of the final product. As a result of endogenous pork muscle endo- and exopeptidases, many medium- and short-chain peptides are released from muscle proteins. Many of them have been isolated, identified, and characterized, and some peptides have been reported to exert relevant bioactivity with potential benefit for human health. However, little attention has been given to di- and tripeptides, which are far less known, although they have received increasing attention in recent years due to their high potential relevance in terms of bioactivity and role in taste development. This review gathers the current knowledge about di- and tripeptides, regarding their bioactivity and sensory properties and focusing on their generation during long-term processing such as dry-cured pork meats.
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5
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Oliveira WQD, Sousa PHMD, Pastore GM. Olfactory and gustatory disorders caused by COVID-19: How to regain the pleasure of eating? Trends Food Sci Technol 2022; 122:104-109. [PMID: 35039714 PMCID: PMC8755554 DOI: 10.1016/j.tifs.2022.01.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 01/03/2022] [Accepted: 01/10/2022] [Indexed: 12/16/2022]
Abstract
Background Recently, anosmia and ageusia (and their variations) have been reported as frequent symptoms of COVID-19. Olfactory and gustatory stimuli are essential in the perception and pleasure of eating. Disorders in sensory perception may influence appetite and the intake of necessary nutrients when recovering from COVID-19. In this short commentary, taste and smell disorders were reported and correlated for the first time with food science. Scope and approach The objective of this short commentary is to report that taste and smell disorders resulted from COVID-19 may impact eating pleasure and nutrition. It also points out important technologies and trends that can be considered and improved in future studies. Key findings and conclusions Firmer food textures can stimulate the trigeminal nerve, and more vibrant colors are able to increase the modulation of brain metabolism, stimulating pleasure. Allied to this, encapsulation technology enables the production of new food formulations, producing agonist and antagonist agents to trigger or block specific sensations. Therefore, opportunities and innovations in the food industry are wide and multidisciplinary discussions are needed.
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Affiliation(s)
- Williara Queiroz de Oliveira
- Laboratory of Bioflavours and Bioactive Compounds, Department of Food Science, Faculty of Food Engineering, University of Campinas, 13083-862, Campinas, SP, Brazil
| | - Paulo Henrique Machado De Sousa
- Department of Food Technology, Federal University of Ceará, Av. Mister Hull, 2977, Pici University Campus, Fortaleza, Ceará, ZIP 60356-000, Brazil
| | - Glaucia Maria Pastore
- Laboratory of Bioflavours and Bioactive Compounds, Department of Food Science, Faculty of Food Engineering, University of Campinas, 13083-862, Campinas, SP, Brazil
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Nishimura K, Ijiri D, Shimamoto S, Takaya M, Ohtsuka A, Goto T. Genetic effect on free amino acid contents of egg yolk and albumen using five different chicken genotypes under floor rearing system. PLoS One 2021; 16:e0258506. [PMID: 34624067 PMCID: PMC8500412 DOI: 10.1371/journal.pone.0258506] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/28/2021] [Indexed: 01/24/2023] Open
Abstract
Chicken eggs play an important role as food resources in the world. Although genetic effects on yolk and albumen contents have been reported, the number of chicken genotypes analyzed so far is still limited. To investigate the effect of genetic background on 10 egg traits, 19 yolk amino acid traits, and 19 albumen amino acid traits, we evaluated a total of 58 eggs from five genotypes: two Japanese indigenous breeds (Ukokkei and Nagoya) and three hybrids (Araucana cross, Kurohisui, and Boris Brown) under a floor rearing system. One-way ANOVA revealed significant effects of genotype on 10 egg traits, 8 yolk amino acids (Asp, Glu, Ser, Gly, Thr, Tyr, Cys, and Leu), and 11 albumen amino acids (Asp, Glu, Asn, Ser, Gln, His, Ala, Tyr, Trp, Phe, and Ile) contents. Moderate to strong positive phenotypic correlations among traits within each trait category (size and weight traits, yolk amino acid traits, and albumen amino acid traits), whereas there were basically no or weak correlations among the trait categories. However, a unique feature was found in the Araucana cross indicating moderate positive correlations of amino acids between yolk and albumen. These results suggest that genetic factors can modify not only the size and weight of the egg and eggshell color but also yolk and albumen free amino acids contents.
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Affiliation(s)
- Kenji Nishimura
- Department of Life and Food Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Daichi Ijiri
- Department of Biochemical Science and Technology, Kagoshima University, Korimoto, Kagoshima, Japan
| | - Saki Shimamoto
- Department of Biochemical Science and Technology, Kagoshima University, Korimoto, Kagoshima, Japan
- Graduate School of Science and Technology, Niigata University, Niigata, Japan
| | - Masahiro Takaya
- Department of Life and Food Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
- Hokkaido Tokachi Area Regional Food Processing Technology Center, Tokachi Foundation, Obihiro, Japan
| | - Akira Ohtsuka
- Department of Biochemical Science and Technology, Kagoshima University, Korimoto, Kagoshima, Japan
| | - Tatsuhiko Goto
- Department of Life and Food Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
- Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
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7
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Wu B, Eldeghaidy S, Ayed C, Fisk ID, Hewson L, Liu Y. Mechanisms of umami taste perception: From molecular level to brain imaging. Crit Rev Food Sci Nutr 2021; 62:7015-7024. [PMID: 33998842 DOI: 10.1080/10408398.2021.1909532] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Due to unique characteristics, umami substances have gained much attention in the food industry during the past decade as potential replacers to sodium or fat to increase food palatability. Umami is not only known to increase appetite, but also to increase satiety, and hence could be used to control food intake. Therefore, it is important to understand the mechanism(s) involved in umami taste perception. This review discusses current knowledge of the mechanism(s) of umami perception from receptor level to human brain imaging. New findings regarding the molecular mechanisms for detecting umami tastes and their pathway(s), and the peripheral and central coding to umami taste are reviewed. The representation of umami in the human brain and the individual variation in detecting umami taste and associations with genotype are discussed. The presence of umami taste receptors in the gastrointestinal tract, and the interactions between the brain and gut are highlighted. The review concludes that more research is required into umami taste perception to include not only oral umami taste perception, but also the wider "whole body" signaling mechanisms, to explore the interaction between the brain and gut in response to umami perception and ingestion.
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Affiliation(s)
- Ben Wu
- Department of Food Science & Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Sally Eldeghaidy
- Division of Food, Nutrition and Dietetics, and Future Food Beacon, School of Biosciences, University of Nottingham, Loughborough, Leicestershire, UK.,Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University Park Campus, University of Nottingham, UK
| | - Charfedinne Ayed
- Division of Food, Nutrition and Dietetics, School of Biosciences, University of Nottingham, Loughborough, Leicestershire, UK
| | - Ian D Fisk
- Division of Food, Nutrition and Dietetics, School of Biosciences, University of Nottingham, Loughborough, Leicestershire, UK.,The University of Adelaide, North Terrace, Adelaide, South Australia, Australia
| | - Louise Hewson
- Division of Food, Nutrition and Dietetics, School of Biosciences, University of Nottingham, Loughborough, Leicestershire, UK
| | - Yuan Liu
- Department of Food Science & Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
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8
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Luchiari HR, Giordano RJ, Sidman RL, Pasqualini R, Arap W. Does the RAAS play a role in loss of taste and smell during COVID-19 infections? THE PHARMACOGENOMICS JOURNAL 2021; 21:109-115. [PMID: 33323946 PMCID: PMC7737200 DOI: 10.1038/s41397-020-00202-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 11/17/2020] [Accepted: 11/19/2020] [Indexed: 01/05/2023]
Affiliation(s)
- Heloise R Luchiari
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil
| | - Ricardo J Giordano
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil.
| | - Richard L Sidman
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Renata Pasqualini
- Rutgers Cancer Institute of New Jersey and Division of Cancer Biology, Department of Radiation Oncology, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Wadih Arap
- Rutgers Cancer Institute of New Jersey and Division of Hematology/Oncology, Department of Medicine, Rutgers New Jersey Medical School, Newark, NJ, USA.
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9
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Schmidt CV, Olsen K, Mouritsen OG. Umami synergy as the scientific principle behind taste-pairing champagne and oysters. Sci Rep 2020; 10:20077. [PMID: 33208820 PMCID: PMC7676262 DOI: 10.1038/s41598-020-77107-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 11/06/2020] [Indexed: 12/03/2022] Open
Abstract
Food and flavour pairing are commonly used as an empirically based phenomenology by chefs and food innovators for creating delicious dishes. However, there is little if any science behind the pairing systems used, and it appears that pairing is determined by food culture and tradition rather than by chemical food composition. In contrast, the pairing implied by the synergy in the umami taste, elicited by free glutamate and free nucleotides, is scientifically founded on an allosteric action at the umami receptor, rendering eggs-bacon and cheese-ham delicious companions. Based on measurement of umami compounds in champagnes and oysters we suggest that a reason why champagne and oysters are considered good companions may be the presence of free glutamate in champagne, and free glutamate and 5′-nucleotides in oysters. By calculations of the effective umami potential we reveal which combinations of oysters and champagnes lead to the strongest umami taste. We also show that glutamate levels and total amount of free amino acids are higher in aged champagnes with long yeast contact, and that the European oyster (Ostrea edulis) has higher free glutamate and nucleotide content than the Pacific oyster (Crassostrea gigas) and is thus a better candidate to elicit synergistic umami taste.
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Affiliation(s)
- Charlotte Vinther Schmidt
- Department of Food Science, Taste for Life and Design and Consumer Behavior, University of Copenhagen, Rolighedsvej 26, 1958, Frederiksberg, Denmark
| | - Karsten Olsen
- Department of Food Science, Taste for Life and Design and Consumer Behavior, University of Copenhagen, Rolighedsvej 26, 1958, Frederiksberg, Denmark
| | - Ole G Mouritsen
- Department of Food Science, Taste for Life and Design and Consumer Behavior, University of Copenhagen, Rolighedsvej 26, 1958, Frederiksberg, Denmark.
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10
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Jeong JY, Kim M, Ji SY, Baek YC, Lee S, Oh YK, Reddy KE, Seo HW, Cho S, Lee HJ. Metabolomics Analysis of the Beef Samples with Different Meat Qualities and Tastes. Food Sci Anim Resour 2020; 40:924-937. [PMID: 33305277 PMCID: PMC7713764 DOI: 10.5851/kosfa.2020.e59] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 07/24/2020] [Accepted: 07/28/2020] [Indexed: 11/25/2022] Open
Abstract
The purpose of this study was to investigate the meat metabolite profiles related
to differences in beef quality attributes (i.e., high-marbled and low-marbled
groups) using nuclear magnetic resonance (NMR) spectroscopy. The beef of
different marbling scores showed significant differences in water content and
fat content. High-marbled meat had mainly higher taste compounds than
low-marbled meat. Metabolite analysis showed differences between two marbling
groups based on partial least square discriminant analysis (PLS-DA). Metabolites
identified by PLS-DA, such as N,N-dimethylglycine, creatine, lactate, carnosine,
carnitine, sn-glycero-3-phosphocholine, betaine, glycine, glucose, alanine,
tryptophan, methionine, taurine, tyrosine, could be directly linked to marbling
groups. Metabolites from variable importance in projection plots were identified
and estimated high sensitivity as candidate markers for beef quality attributes.
These potential markers were involved in beef taste-related pathways including
carbohydrate and amino acid metabolism. Among these metabolites, carnosine,
creatine, glucose, and lactate had significantly higher in high-marbled meat
compared to low-marbled meat (p<0.05). Therefore, these results will
provide an important understanding of the roles of taste-related metabolites in
beef quality attributes. Our findings suggest that metabolomics analysis of
taste compounds and meat quality may be a powerful method for the discovery of
novel biomarkers underlying the quality of beef products.
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Affiliation(s)
- Jin Young Jeong
- Animal Nutrition & Physiology Team, National Institute of Animal Science, Wanju 55365, Korea
| | - Minseok Kim
- Animal Nutrition & Physiology Team, National Institute of Animal Science, Wanju 55365, Korea.,Department of Animal Science, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea
| | - Sang-Yun Ji
- Animal Nutrition & Physiology Team, National Institute of Animal Science, Wanju 55365, Korea
| | - Youl-Chang Baek
- Animal Nutrition & Physiology Team, National Institute of Animal Science, Wanju 55365, Korea
| | - Seul Lee
- Animal Nutrition & Physiology Team, National Institute of Animal Science, Wanju 55365, Korea
| | - Young Kyun Oh
- Animal Nutrition & Physiology Team, National Institute of Animal Science, Wanju 55365, Korea
| | - Kondreddy Eswar Reddy
- Animal Nutrition & Physiology Team, National Institute of Animal Science, Wanju 55365, Korea
| | - Hyun-Woo Seo
- Animal Products Utilization Division, National Institute of Animal Science, Wanju 55365, Korea
| | - Soohyun Cho
- Animal Products Utilization Division, National Institute of Animal Science, Wanju 55365, Korea
| | - Hyun-Jeong Lee
- Animal Nutrition & Physiology Team, National Institute of Animal Science, Wanju 55365, Korea.,Dairy Science Division, National Institute of Animal Science, Cheonan 31000, Korea
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11
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Dutta Banik D, Benfey ED, Martin LE, Kay KE, Loney GC, Nelson AR, Ahart ZC, Kemp BT, Kemp BR, Torregrossa AM, Medler KF. A subset of broadly responsive Type III taste cells contribute to the detection of bitter, sweet and umami stimuli. PLoS Genet 2020; 16:e1008925. [PMID: 32790785 PMCID: PMC7425866 DOI: 10.1371/journal.pgen.1008925] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 06/10/2020] [Indexed: 12/20/2022] Open
Abstract
Taste receptor cells use multiple signaling pathways to detect chemicals in potential food items. These cells are functionally grouped into different types: Type I cells act as support cells and have glial-like properties; Type II cells detect bitter, sweet, and umami taste stimuli; and Type III cells detect sour and salty stimuli. We have identified a new population of taste cells that are broadly tuned to multiple taste stimuli including bitter, sweet, sour, and umami. The goal of this study was to characterize these broadly responsive (BR) taste cells. We used an IP3R3-KO mouse (does not release calcium (Ca2+) from internal stores in Type II cells when stimulated with bitter, sweet, or umami stimuli) to characterize the BR cells without any potentially confounding input from Type II cells. Using live cell Ca2+ imaging in isolated taste cells from the IP3R3-KO mouse, we found that BR cells are a subset of Type III cells that respond to sour stimuli but also use a PLCβ signaling pathway to respond to bitter, sweet, and umami stimuli. Unlike Type II cells, individual BR cells are broadly tuned and respond to multiple stimuli across different taste modalities. Live cell imaging in a PLCβ3-KO mouse confirmed that BR cells use this signaling pathway to respond to bitter, sweet, and umami stimuli. Short term behavioral assays revealed that BR cells make significant contributions to taste driven behaviors and found that loss of either PLCβ3 in BR cells or IP3R3 in Type II cells caused similar behavioral deficits to bitter, sweet, and umami stimuli. Analysis of c-Fos activity in the nucleus of the solitary tract (NTS) also demonstrated that functional Type II and BR cells are required for normal stimulus induced expression. We use our taste system to decide if we are going to consume or reject a potential food item. This is critical for survival, as we need energy to live but also need to avoid potentially toxic compounds. Therefore, it is important to understand how the taste cells in our mouth detect the chemicals in food and send a message to our brain. Signals from the taste cells form a code that conveys information about the nature of the potential food item to the brain. How this taste coding works is not well understood. Currently, it is thought that taste cells are primarily selective for each taste stimuli and only detect either bitter, sweet, sour, salt, or umami (amino acids) compounds. Our study describes a new population of taste cells that can detect multiple types of stimuli, including chemicals from different taste qualities. Thus, taste cells can be either selective or generally responsive to stimuli which is similar to the cells in the brain that process taste information. The presence of these broadly responsive taste cells provides new insight into how taste information is sent to the brain for processing.
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Affiliation(s)
- Debarghya Dutta Banik
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Eric D. Benfey
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Laura E. Martin
- Department of Psychology, University at Buffalo, Buffalo, New York, United States of America
| | - Kristen E. Kay
- Department of Psychology, University at Buffalo, Buffalo, New York, United States of America
| | - Gregory C. Loney
- Department of Psychology, University at Buffalo, Buffalo, New York, United States of America
| | - Amy R. Nelson
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Zachary C. Ahart
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Barrett T. Kemp
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Bailey R. Kemp
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Ann-Marie Torregrossa
- Department of Psychology, University at Buffalo, Buffalo, New York, United States of America
- Center for Ingestive Behavior Research, University at Buffalo, Buffalo, New York, United States of America
| | - Kathryn F. Medler
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
- Center for Ingestive Behavior Research, University at Buffalo, Buffalo, New York, United States of America
- * E-mail:
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12
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Tian M, Heng J, Song H, Zhang Y, Chen F, Guan W, Zhang S. Branched chain amino acids stimulate gut satiety hormone cholecystokinin secretion through activation of the umami taste receptor T1R1/T1R3 using an in vitro porcine jejunum model. Food Funct 2019; 10:3356-3367. [PMID: 31098606 DOI: 10.1039/c9fo00228f] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Branched chain amino acids (BCAAs) are essential amino acids involved in regulation of feed intake. The function of BCAAs on the central nervous system has been extensively studied, but effects of BCAAs on secretion of gut satiety hormones and their underlying mechanisms are largely unknown. In this study, we evaluated the distribution of gut hormones and amino acid receptors in the porcine GI tract and found cholecystokinin (CCK) and taste dimeric receptor type 1 member 1/3 (T1R1/T1R3) were predominantly expressed in the jejunum and functionally interrelated. We further evaluated the effects of l-leucine, l-isoleucine, l-valine, and BCAAs on CCK and T1R1/T1R3 expression in porcine jejunum tissue. Our data demonstrated that stimulation of porcine jejunum tissue with 10 mM l-leucine, l-isoleucine or BCAAs mix (l-leucine : l-isoleucine : l-valine = 1 : 0.51 : 0.63) for 2 hours significantly increased mRNA expression and protein abundance of T1R1/T1R3 and secretion of CCK (P < 0.05). However, the l-valine treatment only increased the mRNA and protein abundance of T1R1 and T1R3 (P < 0.05), but not CCK secretion (P > 0.10). l-Leucine-, l-isoleucine- or BCAAs mix-induced CCK secretion was significantly decreased after tissues were pretreated with lactisole, a T1R1/T1R3 inhibitor (P < 0.05). Furthermore, the increased mRNA and protein abundance of T1R1/T1R3 were also largely attenuated by blocking T1R1/T1R3 with lactisole (P < 0.05). l-Leucine, l-isoleucine and BCAAs mix appeared to induce the gut satiety hormone CCK secretion through jejunal T1R1/T1R3. These results indicate over-supplementation with BCAAs in the diet might decrease food intake in swine and humans through gastrointestinal feedback.
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Affiliation(s)
- Min Tian
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, People's Republic of China.
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13
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Wang H, Murthy KS, Grider JR. Expression patterns of L-amino acid receptors in the murine STC-1 enteroendocrine cell line. Cell Tissue Res 2019; 378:471-483. [PMID: 31410629 DOI: 10.1007/s00441-019-03074-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 07/08/2019] [Indexed: 12/14/2022]
Abstract
Regulation of gut function depends on the detection and response to luminal contents. Luminal L-amino acids (L-AA) are detected by several receptors including metabotropic glutamate receptors 1 and 4 (mGluR1 and mGluR4), calcium-sensing receptor (CaSR), GPRC family C group 6 subtype A receptor (GPRC6A) and umami taste receptor heterodimer T1R1/T1R3. Here, we show that murine mucosal homogenates and STC-1 cells, a murine enteroendocrine cell line, express mRNA for all L-AA receptors. Immunohistochemical analysis demonstrated the presence of all L-AA receptors on STC-1 with CaSR being most commonly expressed and T1R1 least expressed (35% versus 15% of cells); mGluRs and GPRC6a were intermediate (~ 20% of cells). Regarding coexpression of L-AA receptors, the mGluRs and T1R1 were similarly coexpressed with CaSR (10-12% of cells) whereas GPRC6a was coexpressed least (7% of cells). mGluR1 was coexpressed with GPRC6a in 11% of cells whereas coexpression between other receptors was less (2-8% of cells). CaSR and mGluR1 were coexpressed with glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) in 20-25% of cells whereas T1R1 and GPRC6a were coexpressed with GLP-1 and PYY less (8-12% of cells). Only mGluR4 showed differential coexpression with GLP-1 (13%) and PYY (21%). L-Phenylalanine (10 mM) caused a 3-fold increase in GLP-1 release, which was strongly inhibited by siRNA to CaSR indicating functional coupling of CaSR to GLP-1 release. The results suggest that not all STC-1 cells express (and coexpress) L-AA receptors to the same extent and that the pattern of response likely depends on the pattern of expression of L-AA receptors.
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Affiliation(s)
- Hongxia Wang
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences (VPENS), Virginia Commonwealth University, Box 908551, Richmond, VA, 23298, USA
| | - Karnam S Murthy
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences (VPENS), Virginia Commonwealth University, Box 908551, Richmond, VA, 23298, USA
| | - John R Grider
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences (VPENS), Virginia Commonwealth University, Box 908551, Richmond, VA, 23298, USA.
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14
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Abstract
The study of taste has been guided throughout much of its history by the conceptual framework of psychophysics, where the focus was on quantification of the subjective experience of the taste sensations. By the mid-20th century, data from physiologic studies had accumulated sufficiently to assemble a model for the function of receptors that must mediate the initial stimulus of tastant molecules in contact with the tongue. But the study of taste as a receptor-mediated event did not gain momentum until decades later when the actual receptor proteins and attendant signaling mechanisms were identified and localized to the highly specialized taste-responsive cells of the tongue. With those discoveries a new opportunity to examine taste as a function of receptor activity has come into focus. Pharmacology is the science designed specifically for the experimental interrogation and quantitative characterization of receptor function at all levels of inquiry from molecules to behavior. This review covers the history of some of the major concepts that have shaped thinking and experimental approaches to taste, the seminal discoveries that have led to elucidation of receptors for taste, and how applying principles of receptor pharmacology can enhance understanding of the mechanisms of taste physiology and perception.
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Affiliation(s)
- R Kyle Palmer
- Opertech Bio, Inc., Pennovation Center, Philadelphia, Pennsylvania
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15
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Analysis of meat quality traits and gene expression profiling of pigs divergent in residual feed intake. Meat Sci 2018; 137:265-274. [DOI: 10.1016/j.meatsci.2017.11.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/08/2017] [Accepted: 11/16/2017] [Indexed: 11/19/2022]
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16
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Blonde GD, Travers SP, Spector AC. Taste sensitivity to a mixture of monosodium glutamate and inosine 5'-monophosphate by mice lacking both subunits of the T1R1+T1R3 amino acid receptor. Am J Physiol Regul Integr Comp Physiol 2018; 314:R802-R810. [PMID: 29443544 DOI: 10.1152/ajpregu.00352.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The taste of l-glutamate and its synergism with 5'-ribonucleotides is thought to be primarily mediated through the T1R1+T1R3 heterodimer in some mammals, including rodents and humans. While knockout (KO) mice lacking either receptor subunit show impaired sensitivity to a range of monosodium glutamate (MSG) concentrations mixed with 2.5 mM inosine 5'-monophosphate (IMP) in amiloride, wild-type (WT) controls can detect this IMP concentration, hindering direct comparison between genotypes. Moreover, some residual sensitivity persists in the KO group, suggesting that the remaining subunit could maintain a limited degree of function. Here, C57BL/6J, 129X1/SvJ, and T1R1+T1R3 double KO mice ( n = 16 each to start the experiment) were trained in a two-response operant task in gustometers and then tested for their ability to discriminate 100 µM amiloride from MSG (starting with 0.6 M) and IMP (starting with 2.5 mM) in amiloride (MSG+I+A). Testing continued with successive dilutions of both MSG and IMP (in amiloride). The two WT strains were similarly sensitive to MSG+I+A ( P > 0.8). KO mice, however, were significantly impaired relative to either WT strain ( P < 0.01), although they were able to detect the highest concentrations. Thus, normal detectability of MSG+I+A requires an intact T1R1+T1R3 receptor, without regard for allelic variation in the T1R3 gene between the WT strains. Nevertheless, residual sensitivity by the T1R1+T1R3 KO mice demonstrates that a T1R-independent mechanism can contribute to the detectability of high concentrations of this prototypical umami compound stimulus.
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Affiliation(s)
- Ginger D Blonde
- Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
| | - Susan P Travers
- Division of Biosciences, College of Dentistry, Ohio State University , Columbus, Ohio
| | - Alan C Spector
- Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
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17
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Targeting gastrointestinal nutrient sensing mechanisms to treat obesity. Curr Opin Pharmacol 2017; 37:16-23. [DOI: 10.1016/j.coph.2017.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 07/20/2017] [Indexed: 12/15/2022]
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18
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Belloir C, Savistchenko J, Neiers F, Taylor AJ, McGrane S, Briand L. Biophysical and functional characterization of the N-terminal domain of the cat T1R1 umami taste receptor expressed in Escherichia coli. PLoS One 2017; 12:e0187051. [PMID: 29084235 PMCID: PMC5662223 DOI: 10.1371/journal.pone.0187051] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 10/12/2017] [Indexed: 11/21/2022] Open
Abstract
Umami taste perception is mediated by the heterodimeric G-protein coupled receptors (GPCRs), formed by the assembly of T1R1 and T1R3 subunits. T1R1 and T1R3 subunits are class C GPCRs whose members share common structural homologies including a long N-terminal domain (NTD) linked to a seven transmembrane domain by a short cysteine-rich region. The NTD of the T1R1 subunit contains the primary binding site for umami stimuli, such as L-glutamate (L-Glu) for humans. Inosine-5’-monophosphate (IMP) binds at a location close to the opening of the T1R1-NTD “flytrap”, thus creating the observed synergistic response between L-Glu and IMP. T1R1/T1R3 binding studies have revealed species-dependent differences. While human T1R1/T1R3 is activated specifically by L-Glu, the T1R1/T1R3 in other species is a broadly tuned receptor, sensitive to a range of L-amino acids. Because domestic cats are obligate carnivores, they display strong preferences for some specific amino acids. To better understand the structural basis of umami stimuli recognition by non-human taste receptors, we measured the binding of selected amino acids to cat T1R1/T1R3 (cT1R1/cT1R3) umami taste receptor. For this purpose, we expressed cT1R1-NTD in bacteria as inclusion bodies. After purification, refolding of the protein was achieved. Circular dichroism spectroscopic studies revealed that cT1R1-NTD was well renatured with evidence of secondary structures. Using size-exclusion chromatography coupled to light scattering, we found that the cT1R1-NTD behaves as a monomer. Ligand binding quantified by intrinsic tryptophan fluorescence showed that cT1R1-NTD is capable of binding L-amino acids with Kd values in the micromolar range. We demonstrated that IMP potentiates L-amino acid binding onto renatured cT1R1-NTD. Interestingly, our results revealed that IMP binds the extracellular domain in the absence of L-amino acids. Thus, this study demonstrates that the feasibility to produce milligram quantities of cT1R1-NTD for functional and structural studies.
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Affiliation(s)
- Christine Belloir
- Centre des Sciences du Goût et de l'Alimentation, INRA, CNRS, Bourgogne Franche-Comté University, AgroSup Dijon, Dijon, France
| | - Jimmy Savistchenko
- Centre des Sciences du Goût et de l'Alimentation, INRA, CNRS, Bourgogne Franche-Comté University, AgroSup Dijon, Dijon, France
| | - Fabrice Neiers
- Centre des Sciences du Goût et de l'Alimentation, INRA, CNRS, Bourgogne Franche-Comté University, AgroSup Dijon, Dijon, France
| | - Andrew J. Taylor
- WALTHAM Centre for Pet Nutrition, Melton Mowbray, Leicestershire, Great Britain
| | - Scott McGrane
- WALTHAM Centre for Pet Nutrition, Melton Mowbray, Leicestershire, Great Britain
| | - Loïc Briand
- Centre des Sciences du Goût et de l'Alimentation, INRA, CNRS, Bourgogne Franche-Comté University, AgroSup Dijon, Dijon, France
- * E-mail:
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19
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Yangyu L, Ranhui X, Xin Z, Jinzhi H, Xin X. [Taste signal transduction and the role of taste receptors in the regulation of microbial infection]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2017; 35:549-554. [PMID: 29188655 DOI: 10.7518/hxkq.2017.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Taste receptors guide individuals to consume nutrients while avoiding potentially noxious substances. Interestingly, recent studies have shown that taste receptors are also expressed beyond the taste buds, including brain, respiratory system, and digestive system, etc. These extragustatory taste receptors play important roles in microbial infection, nutrient uptake and host homeostasis. Mang extragustatory taste receptors have been proposed to sense microorganisms and regulate host innate defense. More importantly, polymorphisms of genes encoding taste receptor, particularly bitter taste receptor, are linked to different innate defensive responses. This review introduces the molecular basis of taste signal transduction, and the role of taste receptors in the regulation of innate immunity during microbial infection were further discussed in detail.
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Affiliation(s)
- Lu Yangyu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Dept. of Conservative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Xi Ranhui
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Dept. of Conservative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Zheng Xin
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Dept. of Conservative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - He Jinzhi
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Dept. of Conservative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Xu Xin
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Dept. of Conservative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
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20
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Eddy MC, Eschle BK, Delay ER. Comparison of the Tastes of L-Alanine and Monosodium Glutamate in C57BL/6J Wild Type and T1r3 Knockout Mice. Chem Senses 2017; 42:563-573. [PMID: 28605507 DOI: 10.1093/chemse/bjx037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2017] [Indexed: 11/12/2022] Open
Abstract
Previous research showed that L-alanine and monosodium L-glutamate elicit similar taste sensations in rats. This study reports the results of behavioral experiments designed to compare the taste capacity of C57BL/6J wild type and T1r3- mice for these 2 amino acids. In conditioned taste aversion (CTA) experiments, wild-type mice exhibited greater sensitivity than knockout mice for both L-amino acids, although knockout mice were clearly able to detect both amino acids at 50 mM and higher concentrations. Generalization of CTA between L-alanine and L-glutamate was bidirectionally equivalent for both mouse genotypes, indicating that both substances elicited similar tastes in both genotypes. This was verified by the discrimination experiments in which both mouse genotypes performed at or near chance levels at 75 and 150 mM. Above 150 mM, discrimination performance improved, suggesting the taste qualities of the 2 L-amino acids are not identical. No differences between knockout and wild-type mice in discrimination ability were detected. These results indicate that while the T1r3 receptor is important for tasting L-alanine and L-glutamate, other receptors are also important for tasting these amino acids.
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Affiliation(s)
- Meghan C Eddy
- Department of Biology and Vermont Chemical Senses Group, University of Vermont,109 Carrigan Drive, Burlington, VT 05405,USA
| | - Benjamin K Eschle
- Department of Biology and Vermont Chemical Senses Group, University of Vermont,109 Carrigan Drive, Burlington, VT 05405,USA
| | - Eugene R Delay
- Department of Biology and Vermont Chemical Senses Group, University of Vermont,109 Carrigan Drive, Burlington, VT 05405,USA
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21
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Xu JJ, Elkaddi N, Garcia-Blanco A, Spielman AI, Bachmanov AA, Chung HY, Ozdener MH. Arginyl dipeptides increase the frequency of NaCl-elicited responses via epithelial sodium channel alpha and delta subunits in cultured human fungiform taste papillae cells. Sci Rep 2017; 7:7483. [PMID: 28790369 PMCID: PMC5548727 DOI: 10.1038/s41598-017-07756-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/12/2017] [Indexed: 12/19/2022] Open
Abstract
Salty taste is one of the five basic tastes and is often elicited by NaCl. Because excess sodium intake is associated with many health problems, it could be useful to have salt taste enhancers that are not sodium based. In this study, the regulation of NaCl-induced responses was investigated in cultured human fungiform taste papillae (HBO) cells with five arginyl dipeptides: Ala-Arg (AR), Arg-Ala (RA), Arg-Pro (RP), Arg-Glu (RE), and Glu-Arg (ER); and two non-arginyl dipeptides: Asp-Asp (DD) and Glu-Asp (ED). AR, RA, and RP significantly increased the number of cell responses to NaCl, whereas no effect was observed with RE, ER, DD, or ED. We also found no effects with alanine, arginine, or a mixture of both amino acids. Pharmacological studies showed that AR significantly increased responses of amiloride-sensitive but not amiloride-insensitive cells. In studies using small interfering RNAs (siRNAs), responses to AR were significantly decreased in cells transfected with siRNAs against epithelial sodium channel ENaCα or ENaCδ compared to untransfected cells. AR dramatically increased NaCl-elicited responses in cells transfected with NHE1 siRNA but not in those transfected with ENaCα or ENaCδ siRNAs. Altogether, AR increased responses of amiloride-sensitive cells required ENaCα and ENaCδ.
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Affiliation(s)
- Jiao-Jiao Xu
- Food and Nutritional Sciences Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Nadia Elkaddi
- Monell Chemical Senses Center, Philadelphia, PA, 19104, USA
| | | | | | | | - Hau Yin Chung
- Food and Nutritional Sciences Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
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22
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Melis M, Tomassini Barbarossa I. Taste Perception of Sweet, Sour, Salty, Bitter, and Umami and Changes Due to l-Arginine Supplementation, as a Function of Genetic Ability to Taste 6-n-Propylthiouracil. Nutrients 2017; 9:E541. [PMID: 28587069 PMCID: PMC5490520 DOI: 10.3390/nu9060541] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/19/2017] [Accepted: 05/23/2017] [Indexed: 01/07/2023] Open
Abstract
Behavioral reaction to different taste qualities affects nutritional status and health. 6-n-Propylthiouracil (PROP) tasting has been reported to be a marker of variation in taste perception, food preferences, and eating behavior, but results have been inconsistent. We showed that l-Arg can enhance the bitterness intensity of PROP, whilst others have demonstrated a suppression of the bitterness of quinine. Here, we analyze the taste perception of sweet, sour, salty, bitter, and umami and the modifications caused by l-Arg supplementation, as a function of PROP-taster status. Taste perception was assessed by testing the ability to recognize, and the responsiveness to, representative solutions of the five primary taste qualities, also when supplemented with l-Arg, in subjects classified as PROP-tasting. Super-tasters, who showed high papilla density, gave higher ratings to sucrose, citric acid, caffeine, and monosodium l-glutamate than non-tasters. l-Arg supplementation mainly modified sucrose perception, enhanced the umami taste, increased NaCl saltiness and caffeine bitterness only in tasters, and decreased citric acid sourness. Our findings confirm the role of PROP phenotype in the taste perception of sweet, sour, and bitter and show its role in umami. The results suggest that l-Arg could be used as a strategic tool to specifically modify taste responses related to eating behaviors.
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Affiliation(s)
- Melania Melis
- Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Monserrato, Cagliari 09042, Italy.
| | - Iole Tomassini Barbarossa
- Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Monserrato, Cagliari 09042, Italy.
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23
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Abstract
In taste buds, glutamate plays a double role as a gustatory stimulus and neuromodulator. The detection of glutamate as a tastant involves several G protein-coupled receptors, including the heterodimer taste receptor type 1, member 1 and 3 as well as metabotropic glutamate receptors (mGluR1 and mGluR4). Both receptor types participate in the detection of glutamate as shown with knockout animals and selective antagonists. At the basal part of taste buds, ionotropic glutamate receptors [N-methyl-d-aspartate (NMDA) and non-NMDA] are expressed and participate in the modulation of the taste signal before its transmission to the brain. Evidence suggests that glutamate has an efferent function on taste cells and modulates the release of other neurotransmitters such as serotonin and ATP. This short article reviews the recent developments in the field with regard to glutamate receptors involved in both functions as well as the influence of glutamate on the taste signal.
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Affiliation(s)
| | - Sue C Kinnamon
- Department of Otolaryngology, University of Colorado, Aurora, CO
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24
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Abstract
The sense of taste, or gustation, is mediated by taste buds, which are housed in specialized taste papillae found in a stereotyped pattern on the surface of the tongue. Each bud, regardless of its location, is a collection of ∼100 cells that belong to at least five different functional classes, which transduce sweet, bitter, salt, sour and umami (the taste of glutamate) signals. Taste receptor cells harbor functional similarities to neurons but, like epithelial cells, are rapidly and continuously renewed throughout adult life. Here, I review recent advances in our understanding of how the pattern of taste buds is established in embryos and discuss the cellular and molecular mechanisms governing taste cell turnover. I also highlight how these findings aid our understanding of how and why many cancer therapies result in taste dysfunction.
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Affiliation(s)
- Linda A Barlow
- Department of Cell and Developmental Biology, Graduate Program in Cell Biology, Stem Cells and Development and the Rocky Mountain Taste and Smell Center, University of Colorado, School Medicine, Anschutz Medical Campus, Aurora, CO 80045, USA
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25
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Metabotropic glutamate receptors are involved in the detection of IMP and L-amino acids by mouse taste sensory cells. Neuroscience 2015; 316:94-108. [PMID: 26701297 DOI: 10.1016/j.neuroscience.2015.12.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 12/03/2015] [Accepted: 12/04/2015] [Indexed: 11/22/2022]
Abstract
G-protein-coupled receptors are thought to be involved in the detection of umami and L-amino acid taste. These include the heterodimer taste receptor type 1 member 1 (T1r1)+taste receptor type 1 member 3 (T1r3), taste and brain variants of mGluR4 and mGluR1, and calcium sensors. While several studies suggest T1r1+T1r3 is a broadly tuned lLamino acid receptor, little is known about the function of metabotropic glutamate receptors (mGluRs) in L-amino acid taste transduction. Calcium imaging of isolated taste sensory cells (TSCs) of T1r3-GFP and T1r3 knock-out (T1r3 KO) mice was performed using the ratiometric dye Fura 2 AM to investigate the role of different mGluRs in detecting various L-amino acids and inosine 5' monophosphate (IMP). Using agonists selective for various mGluRs such as (RS)-3,5-dihydroxyphenylglycine (DHPG) (an mGluR1 agonist) and L-(+)-2-amino-4-phosphonobutyric acid (l-AP4) (an mGluR4 agonist), we evaluated TSCs to determine if they might respond to these agonists, IMP, and three L-amino acids (monopotassium L-glutamate, L-serine and L-arginine). Additionally, we used selective antagonists against different mGluRs such as (RS)-L-aminoindan-1,5-dicarboxylic acid (AIDA) (an mGluR1 antagonist), and (RS)-α-methylserine-O-phosphate (MSOP) (an mGluR4 antagonist) to determine if they can block responses elicited by these L-amino acids and IMP. We found that L-amino acid- and IMP-responsive cells also responded to each agonist. Antagonists for mGluR4 and mGluR1 significantly blocked the responses elicited by IMP and each of the L-amino acids. Collectively, these data provide evidence for the involvement of taste and brain variants of mGluR1 and mGluR4 in L-amino acid and IMP taste responses in mice, and support the concept that multiple receptors contribute to IMP and L-amino acid taste.
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