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Lao H, Chang J, Zhuang H, Song S, Sun M, Yao L, Wang H, Liu Q, Xiong J, Li P, Yu C, Feng T. Novel kokumi peptides from yeast extract and their taste mechanism via an in silico study. Food Funct 2024; 15:2459-2473. [PMID: 38328886 DOI: 10.1039/d3fo04487d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Yeast extract, a widely utilized natural substance in the food industry and biopharmaceutical field, holds significant potential for flavor enhancement. Kokumi peptides within yeast extracts were isolated through ultrafiltration and gel chromatography, followed by identification using liquid chromatography tandem mass spectrometry (LC-MS/MS). Two peptides, IQGFK and EDFFVR, were identified and synthesized using solid-phase methods based on molecular docking outcomes. Sensory evaluations and electronic tongue analyses conducted with chicken broth solutions revealed taste thresholds of 0.12 mmol L-1 for IQGFK and 0.16 mmol L-1 for EDFFVR, respectively, and both peptides exhibited kokumi properties. Additionally, through molecular dynamics simulations, the binding mechanisms between these peptides and the calcium-sensing receptor (CaSR) were explored. The findings indicated stable binding of both peptides to the receptor. IQGFK primarily interacted through electrostatic interactions, with key binding sites including Asp275, Asn102, Pro274, Trp70, Tyr218, and Ser147. EDFFVR mainly engaged via van der Waals energy and polar solvation free energy, with key binding sites being Asp275, Ile416, Pro274, Arg66, Ala298, and Tyr218. This suggests that both peptides can activate the CaSR, thereby inducing kokumi activity. This study provides a theoretical foundation and reference for the screening and identification of kokumi peptides, successfully uncovering two novel kokumi peptides derived from yeast extract.
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Affiliation(s)
- Haofeng Lao
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai, 201418, People's Republic of China.
| | - Jincui Chang
- D.CO International Food Co., Ltd, Jiaozuo, 454850, People's Republic of China.
| | - Haining Zhuang
- School of Food and Tourism, Shanghai Urban Construction Vocational College, No. 2080, Nanting Road, Shanghai, 201415, People's Republic of China.
| | - Shiqing Song
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai, 201418, People's Republic of China.
| | - Min Sun
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai, 201418, People's Republic of China.
| | - Lingyun Yao
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai, 201418, People's Republic of China.
| | - Huatian Wang
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai, 201418, People's Republic of China.
| | - Qian Liu
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai, 201418, People's Republic of China.
| | - Jian Xiong
- Angel Yeast Co., Ltd, Yichang 443000, People's Republic of China.
| | - Pei Li
- Angel Yeast Co., Ltd, Yichang 443000, People's Republic of China.
| | - Chuang Yu
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai, 201418, People's Republic of China.
| | - Tao Feng
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai, 201418, People's Republic of China.
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Bigiani A, Rhyu M. Effect of kokumi taste-active γ-glutamyl peptides on amiloride-sensitive epithelial Na+ channels in rat fungiform taste cells. Biochem Biophys Rep 2023; 33:101400. [DOI: 10.1016/j.bbrep.2022.101400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 11/17/2022] [Accepted: 11/27/2022] [Indexed: 12/03/2022] Open
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3
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Yamamoto T, Inui-Yamamoto C. The flavor-enhancing action of glutamate and its mechanism involving the notion of kokumi. NPJ Sci Food 2023; 7:3. [PMID: 36707516 PMCID: PMC9883458 DOI: 10.1038/s41538-023-00178-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 01/19/2023] [Indexed: 01/28/2023] Open
Abstract
The sodium salt of glutamic acid, or monosodium glutamate (MSG), has two effects in foods: one is to induce a unique taste called umami, which is one of the five basic tastes, and the other is to make food palatable (i.e., flavor-enhancing or seasoning effects). However, the mechanism behind how MSG makes food more palatable remains poorly understood, although many food scientists seem to believe that the umami taste itself plays an important role. Here, we propose an alternative notion regarding this topic based on previous and recent studies. When added to complex food compositions, MSG facilitates the binding of existing kokumi substances to kokumi receptors. In turn, these bound kokumi substances enhance the intensity of umami, sweet, salty, and fatty tastes, resulting in increased palatability accompanied by kokumi flavor, such as thickness, mouthfulness, and continuity. The requisite for sufficient palatability and kokumi flavor is a good balance of umami and kokumi substances. This framework gives a scientifically useful background for providing newly developed foods, including cultured meat and plant-based meat substitutes, with good taste characteristics.
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Affiliation(s)
- Takashi Yamamoto
- grid.448779.10000 0004 1774 521XHealth Science Research Center, Kio University, 4-2-4 Umami-naka, Koryo, Kitakatsuragi, Nara, 635-0832 Japan
| | - Chizuko Inui-Yamamoto
- grid.136593.b0000 0004 0373 3971Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka, 565-0871 Japan
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Oral expressions and functional analyses of the extracellular calcium-sensing receptor (CaSR) in chicken. Sci Rep 2022; 12:17762. [PMID: 36273034 PMCID: PMC9588031 DOI: 10.1038/s41598-022-22512-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/17/2022] [Indexed: 01/19/2023] Open
Abstract
In vertebrates, the extracellular calcium-sensing receptor (CaSR) plays a key role in calcium homeostasis by sensing slight changes in extracellular Ca2+. CaSR is also expressed in mammals including rodent taste cells and is involved in sensing kokumi, a rich, savory quality that enhances the intensities of salty, sweet, and umami tastes. In this study, we focused on chicken CaSR (cCaSR) since calcium is an essential nutrient that is necessary for making eggshell and for the extremely rapid initial growth of bones. First we confirmed that cCaSR is expressed in taste cells. Next we cloned the cCaSR gene from kidney and transiently transfected human embryonic kidney 293 T (HEK293T) cells with the recombinant cCaSR, or empty vector and looked for the agonists and allosteric modulators (including kokumi substances) of cCaSR by Ca2+ imaging. We found that cCaSR was activated by extracellular Ca2+ and Mg2+ in a dose dependent manner. Several L-amino acids and kokumi substances such as glutathione enhanced the response of cCaSR. In addition, NPS2143 as a negative allosteric modulator of human CaSR negatively modulated the response of cCaSR. These results suggest that cCaSR can sense extracellular Ca2+ and Mg2+ as well as positive and negative allosteric modulators. Taken together, the results imply that CaSR might be a multifunctional receptor for calcium, amino acids, and kokumi substances in chicken. The present finding that functional CaSR is expressed in the chicken oral tissues will allow us to further elucidate the physiological role of CaSR in the chickens' taste sense, and to create new feeds that will contribute to the poultry industry.
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Guha S, Majumder K. Comprehensive Review of γ-Glutamyl Peptides (γ-GPs) and Their Effect on Inflammation Concerning Cardiovascular Health. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:7851-7870. [PMID: 35727887 DOI: 10.1021/acs.jafc.2c01712] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
γ-Glutamyl peptides (γ-GPs) are a group of peptides naturally found in various food sources. The unique γ-bond potentially enables them to resist gastrointestinal digestion and offers high stability in vivo with a longer half-life. In recent years, these peptides have caught researchers' attention due to their ability to impart kokumi taste and elicit various physiological functions via the allosteric activation of the calcium-sensing receptor (CaSR). This review discusses the various food sources of γ-glutamyl peptides, different synthesis modes, allosteric activation of CaSR for taste perception, and associated multiple biological functions they can exhibit, with a special emphasis on their role in modulating chronic inflammation concerning cardiovascular health.
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Affiliation(s)
- Snigdha Guha
- Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Kaustav Majumder
- Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
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6
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Fine-tuning of epithelial taste bud organoid to promote functional recapitulation of taste reactivity. Cell Mol Life Sci 2022; 79:211. [PMID: 35344108 PMCID: PMC8958342 DOI: 10.1007/s00018-022-04242-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/23/2022] [Accepted: 03/09/2022] [Indexed: 11/03/2022]
Abstract
Taste stem/progenitor cells from posterior mouse tongues have been used to generate taste bud organoids. However, the inaccessible location of taste receptor cells is observed in conventional organoids. In this study, we established a suspension-culture method to fine-tune taste bud organoids by apicobasal polarity alteration to form the accessible localization of taste receptor cells. Compared to conventional Matrigel-embedded organoids, suspension-cultured organoids showed comparable differentiation and renewal rates to those of taste buds in vivo and exhibited functional taste receptor cells and cycling progenitor cells. Accessible taste receptor cells enabled the direct application of calcium imaging to evaluate the taste response. Moreover, suspension-cultured organoids can be genetically altered. Suspension-cultured taste bud organoids harmoniously integrated with the recipient lingual epithelium, maintaining the taste receptor cells and gustatory innervation capacity. We propose that suspension-cultured organoids may provide an efficient model for taste research, including taste bud development, regeneration, and transplantation.
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OUP accepted manuscript. Chem Senses 2022; 47:6581352. [DOI: 10.1093/chemse/bjac008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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8
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Mizuta H, Kumamoto N, Ugawa S, Yamamoto T. Additive Effects of L-Ornithine on Preferences to Basic Taste Solutions in Mice. Nutrients 2021; 13:3749. [PMID: 34836006 PMCID: PMC8623908 DOI: 10.3390/nu13113749] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/15/2021] [Accepted: 10/22/2021] [Indexed: 11/16/2022] Open
Abstract
In addition to the taste receptors corresponding to the six basic taste qualities-sweet, salty, sour, bitter, umami, and fatty-another type of taste receptor, calcium-sensing receptor (CaSR), is found in taste-bud cells. CaSR is called the 'kokumi' receptor because its agonists increase sweet, salty and umami tastes to induce 'koku', a Japanese word meaning the enhancement of flavor characters such as thickness, mouthfulness, and continuity. Koku is an important factor for enhancing food palatability. However, it is not well known whether other kokumi-receptors and substances exist. Here, we show that ornithine (L-ornithine but not D-ornithine) at low concentrations that do not elicit a taste of its own, enhances preferences to sweet, salty, umami, and fat taste solutions in mice. Increased preference to monosodium glutamate (MSG) was the most dominant effect. Antagonists of G-protein-coupled receptor family C group 6 subtype A (GPRC6A) abolished the additive effect of ornithine on MSG solutions. The additive effects of ornithine on taste stimuli are thought to occur in the oral cavity, and are not considered post-oral events because ornithine's effects were confirmed in a brief-exposure test. Moreover, the additive effects of ornithine and the action of the antagonist were verified in electrophysiological taste nerve responses. Immunohistochemical analysis implied that GPRC6A was expressed in subsets of type II and type III taste cells of mouse circumvallate papillae. These results are in good agreement with those reported for taste modulation involving CaSR and its agonists. The present study suggests that ornithine is a kokumi substance and GPRC6A is a newly identified kokumi receptor.
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Affiliation(s)
- Haruno Mizuta
- Department of Nutrition, Faculty of Health Sciences, Kio University, 4-2-4 Umami-naka, Koryo, Kitakatsuragi, Nara 635-0832, Japan;
| | - Natsuko Kumamoto
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (N.K.); (S.U.)
| | - Shinya Ugawa
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (N.K.); (S.U.)
| | - Takashi Yamamoto
- Department of Nutrition, Faculty of Health Sciences, Kio University, 4-2-4 Umami-naka, Koryo, Kitakatsuragi, Nara 635-0832, Japan;
- Health Science Research Center, Kio University, 4-2-4 Umami-naka, Koryo, Kitakatsuragi, Nara 635-0832, Japan
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9
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Lu Y, Wang J, Soladoye OP, Aluko RE, Fu Y, Zhang Y. Preparation, receptors, bioactivity and bioavailability of γ-glutamyl peptides: A comprehensive review. Trends Food Sci Technol 2021. [DOI: 10.1016/j.tifs.2021.04.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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10
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Demi LM, Taylor BW, Reading BJ, Tordoff MG, Dunn RR. Understanding the evolution of nutritive taste in animals: Insights from biological stoichiometry and nutritional geometry. Ecol Evol 2021; 11:8441-8455. [PMID: 34257909 PMCID: PMC8258225 DOI: 10.1002/ece3.7745] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/04/2021] [Accepted: 05/11/2021] [Indexed: 12/21/2022] Open
Abstract
A major conceptual gap in taste biology is the lack of a general framework for understanding the evolution of different taste modalities among animal species. We turn to two complementary nutritional frameworks, biological stoichiometry theory and nutritional geometry, to develop hypotheses for the evolution of different taste modalities in animals. We describe how the attractive tastes of Na-, Ca-, P-, N-, and C-containing compounds are consistent with principles of both frameworks based on their shared focus on nutritional imbalances and consumer homeostasis. Specifically, we suggest that the evolution of multiple nutritive taste modalities can be predicted by identifying individual elements that are typically more concentrated in the tissues of animals than plants. Additionally, we discuss how consumer homeostasis can inform our understanding of why some taste compounds (i.e., Na, Ca, and P salts) can be either attractive or aversive depending on concentration. We also discuss how these complementary frameworks can help to explain the evolutionary history of different taste modalities and improve our understanding of the mechanisms that lead to loss of taste capabilities in some animal lineages. The ideas presented here will stimulate research that bridges the fields of evolutionary biology, sensory biology, and ecology.
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Affiliation(s)
- Lee M. Demi
- Department of Applied EcologyNorth Carolina State UniversityRaleighNCUSA
| | - Brad W. Taylor
- Department of Applied EcologyNorth Carolina State UniversityRaleighNCUSA
| | | | | | - Robert R. Dunn
- Department of Applied EcologyNorth Carolina State UniversityRaleighNCUSA
- Center for Evolutionary HologenomicsUniversity of CopenhagenCopenhagenDenmark
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11
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von Molitor E, Riedel K, Krohn M, Hafner M, Rudolf R, Cesetti T. Sweet Taste Is Complex: Signaling Cascades and Circuits Involved in Sweet Sensation. Front Hum Neurosci 2021; 15:667709. [PMID: 34239428 PMCID: PMC8258107 DOI: 10.3389/fnhum.2021.667709] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 05/20/2021] [Indexed: 12/13/2022] Open
Abstract
Sweetness is the preferred taste of humans and many animals, likely because sugars are a primary source of energy. In many mammals, sweet compounds are sensed in the tongue by the gustatory organ, the taste buds. Here, a group of taste bud cells expresses a canonical sweet taste receptor, whose activation induces Ca2+ rise, cell depolarization and ATP release to communicate with afferent gustatory nerves. The discovery of the sweet taste receptor, 20 years ago, was a milestone in the understanding of sweet signal transduction and is described here from a historical perspective. Our review briefly summarizes the major findings of the canonical sweet taste pathway, and then focuses on molecular details, about the related downstream signaling, that are still elusive or have been neglected. In this context, we discuss evidence supporting the existence of an alternative pathway, independent of the sweet taste receptor, to sense sugars and its proposed role in glucose homeostasis. Further, given that sweet taste receptor expression has been reported in many other organs, the physiological role of these extraoral receptors is addressed. Finally, and along these lines, we expand on the multiple direct and indirect effects of sugars on the brain. In summary, the review tries to stimulate a comprehensive understanding of how sweet compounds signal to the brain upon taste bud cells activation, and how this gustatory process is integrated with gastro-intestinal sugar sensing to create a hedonic and metabolic representation of sugars, which finally drives our behavior. Understanding of this is indeed a crucial step in developing new strategies to prevent obesity and associated diseases.
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Affiliation(s)
- Elena von Molitor
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany
| | | | | | - Mathias Hafner
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany
| | - Rüdiger Rudolf
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Tiziana Cesetti
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany
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Brouns I, Verckist L, Pintelon I, Timmermans JP, Adriaensen D. Pulmonary Sensory Receptors. ADVANCES IN ANATOMY EMBRYOLOGY AND CELL BIOLOGY 2021; 233:1-65. [PMID: 33950466 DOI: 10.1007/978-3-030-65817-5_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Inge Brouns
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium.
| | - Line Verckist
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
| | - Isabel Pintelon
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
| | - Jean-Pierre Timmermans
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
| | - Dirk Adriaensen
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen (Wilrijk), Belgium
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Abstract
Umami, the fifth taste, has been recognized as a legitimate taste modality only recently relative to the other tastes. Dozens of compounds from vastly different chemical classes elicit a savory (also called umami) taste. The prototypical umami substance glutamic acid or its salt monosodium glutamate (MSG) is present in numerous savory food sources or ingredients such as kombu (edible kelp), beans, soy sauce, tomatoes, cheeses, mushrooms, and certain meats and fish. Derivatives of glutamate (Glu), other amino acids, nucleotides, and small peptides can also elicit or modulate umami taste. In addition, many potent umami tasting compounds structurally unrelated to amino acids, nucleotides, and MSG have been either synthesized or discovered as naturally occurring in plants and other substances. Over the last 20 years several receptors have been suggested to mediate umami taste, including members of the metabotropic and ionotropic Glu receptor families, and more recently, the heterodimeric G protein-coupled receptor, T1R1/T1R3. Careful assessment of representative umami tasting molecules from several different chemical classes shows activation of T1R1/T1R3 with the expected rank order of potency in cell-based assays. Moreover, 5'-ribonucleotides, molecules known to enhance the savory note of Glu, considerably enhance the effect of MSG on T1R1/T1R3 in vitro. Binding sites are found on at least 4 distinct locations on T1R1/T1R3, explaining the propensity of the receptor to being activated or modulated by many structurally distinct compounds and these binding sites allosterically interact to modulate receptor activity. Activation of T1R1/T1R3 by all known umami substances evaluated and the receptor's pharmacological properties are sufficient to explain the basic human sensory experience of savory taste and it is therefore unlikely that other receptors are involved.
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Functional Exploration of the Pulmonary NEB ME. ADVANCES IN ANATOMY, EMBRYOLOGY, AND CELL BIOLOGY 2021; 233:31-67. [PMID: 33950469 DOI: 10.1007/978-3-030-65817-5_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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15
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Ahmad R, Dalziel JE. G Protein-Coupled Receptors in Taste Physiology and Pharmacology. Front Pharmacol 2020; 11:587664. [PMID: 33390961 PMCID: PMC7774309 DOI: 10.3389/fphar.2020.587664] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022] Open
Abstract
Heterotrimeric G protein-coupled receptors (GPCRs) comprise the largest receptor family in mammals and are responsible for the regulation of most physiological functions. Besides mediating the sensory modalities of olfaction and vision, GPCRs also transduce signals for three basic taste qualities of sweet, umami (savory taste), and bitter, as well as the flavor sensation kokumi. Taste GPCRs reside in specialised taste receptor cells (TRCs) within taste buds. Type I taste GPCRs (TAS1R) form heterodimeric complexes that function as sweet (TAS1R2/TAS1R3) or umami (TAS1R1/TAS1R3) taste receptors, whereas Type II are monomeric bitter taste receptors or kokumi/calcium-sensing receptors. Sweet, umami and kokumi receptors share structural similarities in containing multiple agonist binding sites with pronounced selectivity while most bitter receptors contain a single binding site that is broadly tuned to a diverse array of bitter ligands in a non-selective manner. Tastant binding to the receptor activates downstream secondary messenger pathways leading to depolarization and increased intracellular calcium in TRCs, that in turn innervate the gustatory cortex in the brain. Despite recent advances in our understanding of the relationship between agonist binding and the conformational changes required for receptor activation, several major challenges and questions remain in taste GPCR biology that are discussed in the present review. In recent years, intensive integrative approaches combining heterologous expression, mutagenesis and homology modeling have together provided insight regarding agonist binding site locations and molecular mechanisms of orthosteric and allosteric modulation. In addition, studies based on transgenic mice, utilizing either global or conditional knock out strategies have provided insights to taste receptor signal transduction mechanisms and their roles in physiology. However, the need for more functional studies in a physiological context is apparent and would be enhanced by a crystallized structure of taste receptors for a more complete picture of their pharmacological mechanisms.
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Affiliation(s)
- Raise Ahmad
- Food Nutrition and Health Team, Food and Bio-based Products Group, AgResearch, Palmerston North, New Zealand
| | - Julie E Dalziel
- Food Nutrition and Health Team, Food and Bio-based Products Group, AgResearch, Palmerston North, New Zealand
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16
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Li Q, Zhang L, Lametsch R. Current progress in kokumi-active peptides, evaluation and preparation methods: a review. Crit Rev Food Sci Nutr 2020; 62:1230-1241. [DOI: 10.1080/10408398.2020.1837726] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Qian Li
- Department of Food Science, University of Copenhagen, Frederiksberg C, Denmark
| | - Longteng Zhang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - René Lametsch
- Department of Food Science, University of Copenhagen, Frederiksberg C, Denmark
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17
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Sweet proteins lysozyme and thaumatin are protein-type agonists for the calcium-sensing receptor. Biochem Biophys Res Commun 2019; 521:227-231. [PMID: 31635806 DOI: 10.1016/j.bbrc.2019.10.111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 10/13/2019] [Indexed: 11/21/2022]
Abstract
In addition to the maintenance of Ca2+ homeostasis, the calcium-sensing receptor (CaSR) is involved in many diverse physiological functions in the mammalian body. The receptor works as a kokumi taste receptor in taste buds and as a nutrient sensor in the gut, where it regulates the secretion of glycemic response and appetite-related hormones. To identify novel human CaSR (hCaSR) activators from food ingredients, we conducted a screening using a cell-based hCaSR assay. Hen egg-white lysozyme, which is a sweet protein, was found to be a novel orthosteric agonist of hCaSR with an EC50 value of 592 μM. Lysozyme hydrolysate was not able to activate hCaSR, thus suggesting that the protein structure of lysozyme is necessary for hCaSR activation. Thaumatin, which is another sweet protein, also activated hCaSR with an EC50 value of 71 μM. This is the first report that shows hCaSR activation by proteins with molecular weights exceeding 10,000 Da. These results provide a new avenue for the development of hCaSR activators, which could be applicable in food or drugs that modulate taste perception, appetite, or glucose tolerance, in addition to Ca2+ homeostasis.
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Delompré T, Guichard E, Briand L, Salles C. Taste Perception of Nutrients Found in Nutritional Supplements: A Review. Nutrients 2019; 11:nu11092050. [PMID: 31480669 PMCID: PMC6770818 DOI: 10.3390/nu11092050] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/21/2019] [Accepted: 08/28/2019] [Indexed: 12/18/2022] Open
Abstract
Nutritional supplements are prescribed when one’s nutritional status is not conducive to good health. These foodstuffs constitute concentrated sources of nutrients such as vitamins, minerals, amino acids, and fatty acids. For nutritional supplements to be effective, patients must consume the amount that has been prescribed for the recommended period of time. Therefore, special attention must be given to the sensory attributes of these products. Indeed, the presence of active compounds can cause an off-taste or aftertaste. These negative sensations can lead to a reduction in the consumption of nutritional supplements and reduce the effectiveness of the treatment. In this manuscript, we provide an overview of the sensory characteristics and the sensing receptor mechanism of the main compounds present in oral nutritional supplements, such as amino acids, minerals, fatty acids, and vitamins. Part of this article is devoted to the development of new masking strategies and the corresponding potential influence at the industrial level.
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Affiliation(s)
- Thomas Delompré
- CSGA (Centre des Sciences du Goût et de l'Alimentation), AgroSup Dijon, CNRS, INRA, Université de Bourgogne-Franche Comté, 21000 Dijon, France
| | - Elisabeth Guichard
- CSGA (Centre des Sciences du Goût et de l'Alimentation), AgroSup Dijon, CNRS, INRA, Université de Bourgogne-Franche Comté, 21000 Dijon, France
| | - Loïc Briand
- CSGA (Centre des Sciences du Goût et de l'Alimentation), AgroSup Dijon, CNRS, INRA, Université de Bourgogne-Franche Comté, 21000 Dijon, France.
| | - Christian Salles
- CSGA (Centre des Sciences du Goût et de l'Alimentation), AgroSup Dijon, CNRS, INRA, Université de Bourgogne-Franche Comté, 21000 Dijon, France.
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Glutaminase-catalyzed γ-glutamylation to produce CCK secretion-stimulatory γ-[Glu]n-Trp peptides superior to tryptophan. J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.103418] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Gamma glutamyl peptides: The food source, enzymatic synthesis, kokumi-active and the potential functional properties – A review. Trends Food Sci Technol 2019. [DOI: 10.1016/j.tifs.2019.07.022] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Yang J, Bai W, Zeng X, Cui C. γ-[Glu](n=1,2)-Phe/-Met/-Val stimulates gastrointestinal hormone (CCK and GLP-1) secretion by activating the calcium-sensing receptor. Food Funct 2019; 10:4071-4080. [DOI: 10.1039/c9fo00313d] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This study was conducted to discover the effectiveness of dietary peptides (γ-[Glu](n=1,2)-Phe/-Met/-Val) as stimulators of cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1) secretion.
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Affiliation(s)
- Juan Yang
- College of Food Science and Technology
- Zhongkai University of Agriculture and Engineering
- Guangzhou
- China
| | - Weidong Bai
- College of Food Science and Technology
- Zhongkai University of Agriculture and Engineering
- Guangzhou
- China
| | - Xiaofang Zeng
- College of Food Science and Technology
- Zhongkai University of Agriculture and Engineering
- Guangzhou
- China
| | - Chun Cui
- School of Food Science and Engineering
- South China University of Technology
- Guangzhou 510640
- China
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Yang J, Sun-Waterhouse D, Cui C, Dong K, Wang W. Synthesis and Sensory Characteristics of Kokumi γ-[Glu] n-Phe in the Presence of Glutamine and Phenylalanine: Glutaminase from Bacillus amyloliquefaciens or Aspergillus oryzae as the Catalyst. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:8696-8703. [PMID: 28899090 DOI: 10.1021/acs.jafc.7b03419] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The transpeptidase activity of glutaminase from Bacillus amyloliquefaciens (GBA) and Aspergillus oryzae (GAO) to yield γ-[Glu]n-Phe peptides were verified for the first time. In the presence of Gln and Phe, γ-Glu-Phe and γ-Glu-γ-Glu-Phe were synthesized by GAO, and γ-Glu-Phe, γ-Glu-γ-Glu-Phe, γ-Glu-γ-Glu-γ-Glu-Phe, γ-Glu-γ-Glu-γ-Glu-γ-Glu-Phe, and γ-Glu-γ-Glu-γ-Glu-γ-Glu-γ-Glu-Phe were synthesized by GBA. The Km values for the transpeptidation catalyzed by GBA and GAO were 47.88 and 153.92 mM (Phe as the acceptor), 84.89 and 236.47 mM (γ-Glu-Phe as the acceptor), indicating that GBA had a greater affinity than GAO for Phe and γ-Glu-Phe in the transpeptidation reaction. The Km values for the transpeptidation catalyzed by GBA against acceptors, Phe and γ-[Glu](1≤n<5)-Phe (47.88-206.47 mM), increased with an elevated number of γ-glutamyl residue within the acceptor. The optimal conditions for γ-[Glu]n-Phe synthesis were pH 10 and 37 °C for 3 h, 300 mM Gln, 100 mM Phe, 0.05 U/mL GBA. All the γ-[Glu](1≤n≤5)-Phe exhibited astringency in water and imparted a kokumi taste to commercial soy sauce and model chicken broth. The astringent threshold values (2.5-3.92 mM) were approximately 3-fold of the kokumi threshold concentrations (0.78-1.53 mM). γ-[Glu]n-Phe or the post-enzymatic reaction mixture enhanced the umami intensity of commercial soy sauce and model chicken broth.
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Affiliation(s)
- Juan Yang
- School of Food Science and Engineering, South China University of Technology , Guangzhou 510640, China
| | - Dongxiao Sun-Waterhouse
- School of Food Science and Engineering, South China University of Technology , Guangzhou 510640, China
| | - Chun Cui
- School of Food Science and Engineering, South China University of Technology , Guangzhou 510640, China
| | - Keming Dong
- Guangdong Weiwei Biotechnology Co., Ltd. , Guangzhou 510640, China
| | - Wei Wang
- School of Food Science and Engineering, South China University of Technology , Guangzhou 510640, China
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Martin B, Wang R, Cong WN, Daimon CM, Wu WW, Ni B, Becker KG, Lehrmann E, Wood WH, Zhang Y, Etienne H, van Gastel J, Azmi A, Janssens J, Maudsley S. Altered learning, memory, and social behavior in type 1 taste receptor subunit 3 knock-out mice are associated with neuronal dysfunction. J Biol Chem 2017; 292:11508-11530. [PMID: 28522608 DOI: 10.1074/jbc.m116.773820] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 05/03/2017] [Indexed: 12/19/2022] Open
Abstract
The type 1 taste receptor member 3 (T1R3) is a G protein-coupled receptor involved in sweet-taste perception. Besides the tongue, the T1R3 receptor is highly expressed in brain areas implicated in cognition, including the hippocampus and cortex. As cognitive decline is often preceded by significant metabolic or endocrinological dysfunctions regulated by the sweet-taste perception system, we hypothesized that a disruption of the sweet-taste perception in the brain could have a key role in the development of cognitive dysfunction. To assess the importance of the sweet-taste receptors in the brain, we conducted transcriptomic and proteomic analyses of cortical and hippocampal tissues isolated from T1R3 knock-out (T1R3KO) mice. The effect of an impaired sweet-taste perception system on cognition functions were examined by analyzing synaptic integrity and performing animal behavior on T1R3KO mice. Although T1R3KO mice did not present a metabolically disrupted phenotype, bioinformatic interpretation of the high-dimensionality data indicated a strong neurodegenerative signature associated with significant alterations in pathways involved in neuritogenesis, dendritic growth, and synaptogenesis. Furthermore, a significantly reduced dendritic spine density was observed in T1R3KO mice together with alterations in learning and memory functions as well as sociability deficits. Taken together our data suggest that the sweet-taste receptor system plays an important neurotrophic role in the extralingual central nervous tissue that underpins synaptic function, memory acquisition, and social behavior.
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Affiliation(s)
- Bronwen Martin
- From the Metabolism Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Rui Wang
- From the Metabolism Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Wei-Na Cong
- From the Metabolism Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Caitlin M Daimon
- From the Metabolism Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Wells W Wu
- From the Metabolism Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Bin Ni
- the Receptor Pharmacology Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Kevin G Becker
- the Gene Expression and Genomics Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Elin Lehrmann
- the Gene Expression and Genomics Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - William H Wood
- the Gene Expression and Genomics Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Yongqing Zhang
- the Gene Expression and Genomics Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Harmonie Etienne
- the Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, AN-2610 Antwerp, Belgium, and.,the Department of Biomedical Sciences, University of Antwerp, AN-2610 Antwerp, Belgium
| | - Jaana van Gastel
- the Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, AN-2610 Antwerp, Belgium, and.,the Department of Biomedical Sciences, University of Antwerp, AN-2610 Antwerp, Belgium
| | - Abdelkrim Azmi
- the Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, AN-2610 Antwerp, Belgium, and.,the Department of Biomedical Sciences, University of Antwerp, AN-2610 Antwerp, Belgium
| | - Jonathan Janssens
- the Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, AN-2610 Antwerp, Belgium, and.,the Department of Biomedical Sciences, University of Antwerp, AN-2610 Antwerp, Belgium
| | - Stuart Maudsley
- the Receptor Pharmacology Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224, .,the Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, AN-2610 Antwerp, Belgium, and.,the Department of Biomedical Sciences, University of Antwerp, AN-2610 Antwerp, Belgium
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Ishibashi-Shiraishi I, Shiraishi S, Fujita S, Ogawa S, Kaneko M, Suzuki M, Tanaka T. L-Arginine L-Glutamate Enhances Gastric Motor Function in Rats and Dogs and Improves Delayed Gastric Emptying in Dogs. J Pharmacol Exp Ther 2016; 359:238-246. [PMID: 27535977 DOI: 10.1124/jpet.116.234658] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 08/16/2016] [Indexed: 12/20/2022] Open
Abstract
Amino acids are not only constituents of proteins, but also have multiple physiologic functions. Recent findings have revealed that ingested amino acids either activate luminal receptors or are metabolized, causing physiologic reactions in the gastrointestinal (GI) tract. We examined the effect of oral L-arginine L-glutamate (ArgGlu), a pharmaceutical amino acid salt used i.v. for the treatment of hyperammonemia, on gastric motor function in rats and dogs. Gastric emptying was determined using phenol red and 13C-breath test methods, whereas gastric relaxation was determined using the barostat method. ArgGlu (10-30 mg/kg, p.o.) dose-dependently promoted gastric emptying in rats. This effect was dependent on vagus nerve activation and comparable to that of the prokinetic mosapride. Intragastric ArgGlu (3-30 mg/kg intragastrically) also dose-dependently enhanced adaptive relaxation of rat stomachs, which was negated not by vagotomy of gastric branches, but by pretreatment with N omega-nitro-L-arginine methyl ester (20 mg/kg i.v.), a nitric oxide synthase inhibitor. Its relaxing effect on the stomach was also confirmed in dogs and was equally as efficacious as treatment with sumatriptan (1-3 mg/kg s.c.). ArgGlu (30 mg/kg p.o.) significantly reduced the half gastric emptying time in clonidine-induced delayed gastric emptying of solids in dogs, and its effect was comparable to that of cisapride (3 mg/kg p.o.). This study demonstrated that the pharmaceutical ingredient ArgGlu, currently used i.v., enhanced gastric motor function when administered orally, suggesting that it could be a new oral medicine indicated for treatment of upper GI hypofunction or dysfunction like functional dyspepsia.
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Affiliation(s)
| | - Seiji Shiraishi
- Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan
| | - Shinichi Fujita
- Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan
| | - Saori Ogawa
- Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan
| | - Masahiko Kaneko
- Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan
| | - Manabu Suzuki
- Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan
| | - Tatsuro Tanaka
- Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan
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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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Pal Choudhuri S, Delay RJ, Delay ER. L-Amino Acids Elicit Diverse Response Patterns in Taste Sensory Cells: A Role for Multiple Receptors. PLoS One 2015; 10:e0130088. [PMID: 26110622 PMCID: PMC4482487 DOI: 10.1371/journal.pone.0130088] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 05/15/2015] [Indexed: 12/01/2022] Open
Abstract
Umami, the fifth basic taste, is elicited by the L-amino acid, glutamate. A unique characteristic of umami taste is the response potentiation by 5’ ribonucleotide monophosphates, which are also capable of eliciting an umami taste. Initial reports using human embryonic kidney (HEK) cells suggested that there is one broadly tuned receptor heterodimer, T1r1+T1r3, which detects L-glutamate and all other L-amino acids. However, there is growing evidence that multiple receptors detect glutamate in the oral cavity. While much is understood about glutamate transduction, the mechanisms for detecting the tastes of other L-amino acids are less well understood. We used calcium imaging of isolated taste sensory cells and taste cell clusters from the circumvallate and foliate papillae of C57BL/6J and T1r3 knockout mice to determine if other receptors might also be involved in detection of L-amino acids. Ratiometric imaging with Fura-2 was used to study calcium responses to monopotassium L-glutamate, L-serine, L-arginine, and L-glutamine, with and without inosine 5’ monophosphate (IMP). The results of these experiments showed that the response patterns elicited by L-amino acids varied significantly across taste sensory cells. L-amino acids other than glutamate also elicited synergistic responses in a subset of taste sensory cells. Along with its role in synergism, IMP alone elicited a response in a large number of taste sensory cells. Our data indicate that synergistic and non-synergistic responses to L-amino acids and IMP are mediated by multiple receptors or possibly a receptor complex.
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Affiliation(s)
- Shreoshi Pal Choudhuri
- Department of Biology and Vermont Chemosensory Group, The University of Vermont, Burlington, Vermont, United States of America
| | - Rona J. Delay
- Department of Biology and Vermont Chemosensory Group, The University of Vermont, Burlington, Vermont, United States of America
| | - Eugene R. Delay
- Department of Biology and Vermont Chemosensory Group, The University of Vermont, Burlington, Vermont, United States of America
- * E-mail:
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Kim JY, Ho H, Kim N, Liu J, Tu CL, Yenari MA, Chang W. Calcium-sensing receptor (CaSR) as a novel target for ischemic neuroprotection. Ann Clin Transl Neurol 2014; 1:851-66. [PMID: 25540800 PMCID: PMC4265057 DOI: 10.1002/acn3.118] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 08/14/2014] [Accepted: 08/15/2014] [Indexed: 01/04/2023] Open
Abstract
Object Ischemic brain injury is the leading cause for death and long-term disability in patients who suffer cardiac arrest and embolic stroke. Excitotoxicity and subsequent Ca2+-overload lead to ischemic neuron death. We explore a novel mechanism concerning the role of the excitatory extracellular calcium-sensing receptor (CaSR) in the induction of ischemic brain injury. Method Mice were exposed to forebrain ischemia and the actions of CaSR were determined after its genes were ablated specifically in hippocampal neurons or its activities were inhibited pharmacologically. Since the CaSR forms a heteromeric complex with the inhibitory type B γ-aminobutyric acid receptor 1 (GABABR1), we compared neuronal responses to ischemia in mice deficient in CaSR, GABABR1, or both, and in mice injected locally or systemically with a specific CaSR antagonist (or calcilytic) in the presence or absence of a GABABR1 agonist (baclofen). Results Both global and focal brain ischemia led to CaSR overexpression and GABABR1 downregulation in injured neurons. Genetic ablation of Casr genes or blocking CaSR activities by calcilytics rendered robust neuroprotection and preserved learning and memory functions in ischemic mice, partly by restoring GABABR1 expression. Concurrent ablation of Gabbr1 gene blocked the neuroprotection caused by the Casr gene knockout. Coinjection of calcilytics with baclofen synergistically enhanced neuroprotection. This combined therapy remained robust when given 6 h after ischemia. Interpretation Our study demonstrates a novel receptor interaction, which contributes to ischemic neuron death through CaSR upregulation and GABABR1 downregulation, and feasibility of neuroprotection by concurrently targeting these two receptors.
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Affiliation(s)
- Jong Youl Kim
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121 ; Department of Neurology, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Hanson Ho
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Nuri Kim
- Department of Neurology, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Jialing Liu
- Neurological Surgery, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Chia-Ling Tu
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Midori A Yenari
- Department of Neurology, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Wenhan Chang
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
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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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Bachmanov AA, Bosak NP, Lin C, Matsumoto I, Ohmoto M, Reed DR, Nelson TM. Genetics of taste receptors. Curr Pharm Des 2014; 20:2669-83. [PMID: 23886383 PMCID: PMC4764331 DOI: 10.2174/13816128113199990566] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 07/24/2013] [Indexed: 12/19/2022]
Abstract
Taste receptors function as one of the interfaces between internal and external milieus. Taste receptors for sweet and umami (T1R [taste receptor, type 1]), bitter (T2R [taste receptor, type 2]), and salty (ENaC [epithelial sodium channel]) have been discovered in the recent years, but transduction mechanisms of sour taste and ENaC-independent salt taste are still poorly understood. In addition to these five main taste qualities, the taste system detects such noncanonical "tastes" as water, fat, and complex carbohydrates, but their reception mechanisms require further research. Variations in taste receptor genes between and within vertebrate species contribute to individual and species differences in taste-related behaviors. These variations are shaped by evolutionary forces and reflect species adaptations to their chemical environments and feeding ecology. Principles of drug discovery can be applied to taste receptors as targets in order to develop novel taste compounds to satisfy demand in better artificial sweeteners, enhancers of sugar and sodium taste, and blockers of bitterness of food ingredients and oral medications.
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Voznesenskaya A, Tordoff MG. Influence of cross-fostering on preference for calcium chloride in C57BL/6J and PWK/PhJ mice. Physiol Behav 2013; 122:159-62. [PMID: 24041724 DOI: 10.1016/j.physbeh.2013.09.002] [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: 05/22/2013] [Accepted: 09/05/2013] [Indexed: 10/26/2022]
Abstract
We investigated whether maternal influences during the suckling period alter the avidity for calcium, using as models mice from the calcium-preferring PWK/PhJ strain and the calcium-avoiding C57BL/6J strain. We found that milk collected from PWK/PhJ dams had higher calcium concentrations than did milk collected from C57BL/6J dams. Despite this, cross-strain fostering had no effect on adult calcium preferences relative to mice of the same strain that were within-strain fostered or not fostered. Our results indicate that calcium avoidance by C57BL/6J mice and acceptance by PWK/PhJ mice are unaffected by maternal environment during the suckling period.
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Affiliation(s)
- Anna Voznesenskaya
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA, United States; A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, 127994, Russia.
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Lembrechts R, Brouns I, Schnorbusch K, Pintelon I, Kemp PJ, Timmermans JP, Riccardi D, Adriaensen D. Functional expression of the multimodal extracellular calcium-sensing receptor in pulmonary neuroendocrine cells. J Cell Sci 2013; 126:4490-501. [PMID: 23886943 DOI: 10.1242/jcs.131656] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The Ca(2+)-sensing receptor (CaSR) is the master regulator of whole-body extracellular free ionized [Ca(2+)]o. In addition to sensing [Ca(2+)]o, CaSR integrates inputs from a variety of different physiological stimuli. The CaSR is also expressed in many regions outside the [Ca(2+)]o homeostatic system, including the fetal lung where it plays a crucial role in lung development. Here, we show that neuroepithelial bodies (NEBs) of the postnatal mouse lung express a functional CaSR. NEBs are densely innervated groups of neuroendocrine epithelial cells in the lung representing complex sensory receptors in the airways and exhibiting stem cell characteristics. qRT-PCR performed on laser microdissected samples from GAD67-GFP mouse lung cryosections revealed exclusive expression of the CaSR in the NEB microenvironment. CaSR immunoreactivity was present at NEB cells from postnatal day 14 onwards. Confocal imaging of lung slices revealed that NEB cells responded to an increase of [Ca(2+)]o with a rise in intracellular Ca(2+) ([Ca(2+)]i); an effect mimicked by several membrane-impermeant CaSR agonists (e.g. the calcimimetic R-568) and that was blocked by the calcilytic Calhex-231. Block of TRPC channels attenuated the CaSR-dependent increases in [Ca(2+)]i, suggesting that Ca(2+) influx through TRPC channels contributes to the total [Ca(2+)]i signal evoked by the CaSR in NEBs. CaSR also regulated baseline [Ca(2+)]i in NEBs and, through paracrine signaling from Clara-like cells, coordinated intercellular communication in the NEB microenvironment. These data suggest that the NEB CaSR integrates multiple signals converging on this complex chemosensory unit, and is a key regulator of this intrapulmonary airway stem cell niche.
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Affiliation(s)
- Robrecht Lembrechts
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, BE-2020 Antwerp, Belgium
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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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A novel regulatory function of sweet taste-sensing receptor in adipogenic differentiation of 3T3-L1 cells. PLoS One 2013; 8:e54500. [PMID: 23336004 PMCID: PMC3545961 DOI: 10.1371/journal.pone.0054500] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 12/12/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Sweet taste receptor is expressed not only in taste buds but also in nongustatory organs such as enteroendocrine cells and pancreatic beta-cells, and may play more extensive physiological roles in energy metabolism. Here we examined the expression and function of the sweet taste receptor in 3T3-L1 cells. METHODOLOGY/PRINCIPAL FINDINGS In undifferentiated preadipocytes, both T1R2 and T1R3 were expressed very weakly, whereas the expression of T1R3 but not T1R2 was markedly up-regulated upon induction of differentiation (by 83.0 and 3.8-fold, respectively at Day 6). The α subunits of Gs (Gαs) and G14 (Gα14) but not gustducin were expressed throughout the differentiation process. The addition of sucralose or saccharin during the first 48 hours of differentiation considerably reduced the expression of peroxisome proliferator activated receptor γ (PPARγ and CCAAT/enhancer-binding protein α (C/EBPα at Day 2, the expression of aP2 at Day 4 and triglyceride accumulation at Day 6. These anti-adipogenic effects were attenuated by short hairpin RNA-mediated gene-silencing of T1R3. In addition, overexpression of the dominant-negative mutant of Gαs but not YM-254890, an inhibitor of Gα14, impeded the effects of sweeteners, suggesting a possible coupling of Gs with the putative sweet taste-sensing receptor. In agreement, sucralose and saccharin increased the cyclic AMP concentration in differentiating 3T3-L1 cells and also in HEK293 cells heterologously expressing T1R3. Furthermore, the anti-adipogenic effects of sweeteners were mimicked by Gs activation with cholera toxin but not by adenylate cyclase activation with forskolin, whereas small interfering RNA-mediated knockdown of Gαs had the opposite effects. CONCLUSIONS 3T3-L1 cells express a functional sweet taste-sensing receptor presumably as a T1R3 homomer, which mediates the anti-adipogenic signal by a Gs-dependent but cAMP-independent mechanism.
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Crankshaw DJ, Pistilli MJ, O'Brien YM, Sweeney EM, Dockery P, Holloway AC, Morrison JJ. The effects of extracellular calcium-sensing receptor ligands on the contractility of pregnant human myometrium in vitro. Reprod Sci 2013; 20:882-90. [PMID: 23287098 DOI: 10.1177/1933719112468949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Ligands for extracellular calcium-sensing (CaS) receptors inhibit oxytocin-induced contractions of the rat's uterus. In this study, we investigated whether the CaS receptor ligands calindol, cinacalcet, and calhex 231 have similar effects on pregnant human myometrium. We compared their effects to those of the calcium-channel blocker nifedipine. In conventional concentration-effect experiments, both the mean contractile force (MCF) and the maximum amplitude of contractions induced by 1 nmol/L oxytocin were inhibited by nifedipine. Calindol and cinacalcet were ineffective as inhibitors, while calhex-231 produced partial inhibition. When single 10 μmol/L doses were applied calhex-231 produced a slowly developing inhibition, reducing the MCF to 38%, and amplitude to 34%, of vehicle controls after 1 hour. In similar experiments, calindol was ineffective while cinacalcet weakly inhibited only the amplitude. Immunohistochemistry revealed sparse expression of CaS receptors in pregnant human myometrium.
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Affiliation(s)
- Denis J Crankshaw
- Department of Obstetrics and Gynaecology, National University of Ireland-Galway, Ireland.
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Amino acid sensing in the gastrointestinal tract. Amino Acids 2012; 45:451-61. [DOI: 10.1007/s00726-012-1371-2] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 07/14/2012] [Indexed: 12/24/2022]
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Torii K. Brain activation by the umami taste substance monosodium L-glutamate via gustatory and visceral signaling pathways, and its physiological significance due to homeostasis after a meal. J Oral Biosci 2012. [DOI: 10.1016/j.job.2012.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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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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Romanov RA, Rogachevskaja OA, Bystrova MF, Kolesnikov SS. Electrical excitability of taste cells. Mechanisms and possible physiological significance. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2012. [DOI: 10.1134/s1990747812010126] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Maruyama Y, Yasuda R, Kuroda M, Eto Y. Kokumi substances, enhancers of basic tastes, induce responses in calcium-sensing receptor expressing taste cells. PLoS One 2012; 7:e34489. [PMID: 22511946 PMCID: PMC3325276 DOI: 10.1371/journal.pone.0034489] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 03/01/2012] [Indexed: 11/19/2022] Open
Abstract
Recently, we reported that calcium-sensing receptor (CaSR) is a receptor for kokumi substances, which enhance the intensities of salty, sweet and umami tastes. Furthermore, we found that several γ-glutamyl peptides, which are CaSR agonists, are kokumi substances. In this study, we elucidated the receptor cells for kokumi substances, and their physiological properties. For this purpose, we used Calcium Green-1 loaded mouse taste cells in lingual tissue slices and confocal microscopy. Kokumi substances, applied focally around taste pores, induced an increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)) in a subset of taste cells. These responses were inhibited by pretreatment with the CaSR inhibitor, NPS2143. However, the kokumi substance-induced responses did not require extracellular Ca(2+). CaSR-expressing taste cells are a different subset of cells from the T1R3-expressing umami or sweet taste receptor cells. These observations indicate that CaSR-expressing taste cells are the primary detectors of kokumi substances, and that they are an independent population from the influenced basic taste receptor cells, at least in the case of sweet and umami.
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Affiliation(s)
- Yutaka Maruyama
- Institute for Innovation, Ajinomoto Co, Inc, Kawasaki, Japan.
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Uneyama H. Nutritional and physiological significance of luminal glutamate-sensing in the gastrointestinal functions. YAKUGAKU ZASSHI 2012; 131:1699-709. [PMID: 22129863 DOI: 10.1248/yakushi.131.1699] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent evidence indicates that free amino acids are nutrients as well as acting as chemical transmitters within the gastrointestinal tract. Gut glutamate research is the most advanced among 20 amino acids. Free glutamate carries the umami taste sensation on the tongue and a visceral sensation in the gut, especially the stomach. In the field of taste physiology, the physiological meaning of the glutamate-derived chemical sense, the umami taste, has been proposed to be a marker of protein intake. Experimental evidence in gut glutamate physiology strongly supports this hypothesis. Free glutamate is sensed by the abdominal vagus and regulates gastrointestinal functions such as secretion and emptying to accelerate protein digestion. Clinical application of glutamate has also just begun to treat gastrointestinal disorders such as dyspepsia, ulcer, dry mouth and functional dyspepsia. In this review, we introduce recent advances in gut glutamate research and consider the possible contribution of glutamate to health.
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Affiliation(s)
- Hisayuki Uneyama
- Umami Wellness Research Group, Frontier Research Laboratories, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki, Japan.
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Amin A, Murphy KG. Nutritional sensing and its utility in treating obesity. Expert Rev Endocrinol Metab 2012; 7:209-221. [PMID: 30764012 DOI: 10.1586/eem.12.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Obesity remains a major worldwide health problem, with current medical treatments being poorly effective. Nutrient sensing allows organs such as the GI tract and the brain to recognize and respond to fuel substrates such as carbohydrates, protein and fats. Specialized neural and hormonal pathways exist to facilitate and regulate these chemosensory mechanisms. Manipulation of factors involved in either central or peripheral chemosensory pathways may provide possible targets for the manipulation of appetite. However, further research is required to assess the utility of this approach to developing novel anti-obesity agents.
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Affiliation(s)
- Anjali Amin
- a Section of Investigative Medicine, Faculty of Medicine, Imperial College London, 6th Floor, Commonwealth Building, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Kevin G Murphy
- b Section of Investigative Medicine, Faculty of Medicine, Imperial College London, 6th Floor, Commonwealth Building, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
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Abstract
Taste buds are the transducing endorgans of gustation. Each taste bud comprises 50-100 elongated cells, which extend from the basal lamina to the surface of the tongue, where their apical microvilli encounter taste stimuli in the oral cavity. Salts and acids utilize apically located ion channels for transduction, while bitter, sweet and umami (glutamate) stimuli utilize G-protein-coupled receptors (GPCRs) and second-messenger signalling mechanisms. This review will focus on GPCR signalling mechanisms. Two classes of taste GPCRs have been identified, the T1Rs for sweet and umami (glutamate) stimuli and the T2Rs for bitter stimuli. These low affinity GPCRs all couple to the same downstream signalling effectors that include Gβγ activation of phospholipase Cβ2, 1,4,5-inositol trisphosphate mediated release of Ca(2+) from intracellular stores and Ca(2+) -dependent activation of the monovalent selective cation channel, TrpM5. These events lead to membrane depolarization, action potentials and release of ATP as a transmitter to activate gustatory afferents. The Gα subunit, α-gustducin, activates a phosphodiesterase to decrease intracellular cAMP levels, although the precise targets of cAMP have not been identified. With the molecular identification of the taste GPCRs, it has become clear that taste signalling is not limited to taste buds, but occurs in many cell types of the airways. These include solitary chemosensory cells, ciliated epithelial cells and smooth muscle cells. Bitter receptors are most abundantly expressed in the airways, where they respond to irritating chemicals and promote protective airway reflexes, utilizing the same downstream signalling effectors as taste cells.
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Affiliation(s)
- S C Kinnamon
- Department of Otolaryngology, School of Medicine, University of Colorado Denver, Aurora, 80534, USA.
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Golden GJ, Voznesenskaya A, Tordoff MG. Chorda tympani nerve modulates the rat's avoidance of calcium chloride. Physiol Behav 2011; 105:1214-8. [PMID: 22230254 DOI: 10.1016/j.physbeh.2011.12.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 12/21/2011] [Accepted: 12/23/2011] [Indexed: 10/14/2022]
Abstract
Calcium intake depends on orosensory factors, implying the presence of a mechanism for calcium detection in the mouth. To better understand how information about oral calcium is conveyed to the brain, we examined the effects of chorda tympani nerve transection on calcium chloride (CaCl(2)) taste preferences and thresholds in male Wistar rats. The rats were given bilateral transections of the chorda tympani nerve (CTX) or control surgery. After recovery, they received 48-h two-bottle tests with an ascending concentration series of CaCl(2). Whereas control rats avoided CaCl(2) at concentrations of 0.1mM and higher, rats with CTX were indifferent to CaCl(2) concentrations up to 10mM. Rats with CTX had significantly higher preference scores for 0.316 and 3.16 mM CaCl(2) than did control rats. The results imply that the chorda tympani nerve is required for the normal avoidance of CaCl(2) solution.
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Affiliation(s)
- Glen J Golden
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA, USA
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Stimulation of the extracellular Ca2+-sensing receptor by denatonium. Biochem Biophys Res Commun 2011; 416:433-6. [DOI: 10.1016/j.bbrc.2011.11.095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 11/17/2011] [Indexed: 01/13/2023]
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Ozdener MH, Brand JG, Spielman AI, Lischka FW, Teeter JH, Breslin PAS, Rawson NE. Characterization of human fungiform papillae cells in culture. Chem Senses 2011; 36:601-12. [PMID: 21471186 DOI: 10.1093/chemse/bjr012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The ability to maintain human fungiform papillae cells in culture for multiple cell cycles would be of considerable utility for characterizing the molecular, regenerative, and functional properties of these unique sensory cells. Here we describe a method for enzymatically isolating human cells from fungiform papillae obtained by biopsy and maintaining them in culture for more than 7 passages (7 months) without loss of viability and while retaining many of the functional properties of acutely isolated taste cells. Cells in these cultures exhibited increases in intracellular calcium when stimulated with perceptually appropriate concentrations of several taste stimuli, indicating that at least some of the native signaling pathways were present. This system can provide a useful model for molecular studies of the proliferation, differentiation, and physiological function of human fungiform papillae cells.
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Affiliation(s)
- Mehmet Hakan Ozdener
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104-3308, USA.
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Abstract
Compelling evidence of a cell surface receptor sensitive to extracellular calcium was observed as early as the 1980s and was finally realized in 1993 when the calcium-sensing receptor (CaR) was cloned from bovine parathyroid tissue. Initial studies relating to the CaR focused on its key role in extracellular calcium homeostasis, but as the amount of information about the receptor grew it became evident that it was involved in many biological processes unrelated to calcium homeostasis. The CaR responds to a diverse array of stimuli extending well beyond that merely of calcium, and these stimuli can lead to the initiation of a wide variety of intracellular signaling pathways that in turn are able to regulate a diverse range of biological processes. It has been through the examination of the molecular characteristics of the CaR that we now have an understanding of how this single receptor is able to convert extracellular messages into specific cellular responses. Recent CaR-related reviews have focused on specific aspects of the receptor, generally in the context of the CaR's role in physiology and pathophysiology. This review will provide a comprehensive exploration of the different aspects of the receptor, including its structure, stimuli, signalling, interacting protein partners, and tissue expression patterns, and will relate their impact on the functionality of the CaR from a molecular perspective.
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Affiliation(s)
- Aaron L Magno
- Department of Endocrinology and Diabetes, First Floor, C Block, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands 6009, Western Australia, Australia
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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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San Gabriel A, Nakamura E, Uneyama H, Torii K. Taste, visceral information and exocrine reflexes with glutamate through umami receptors. THE JOURNAL OF MEDICAL INVESTIGATION 2010; 56 Suppl:209-17. [PMID: 20224183 DOI: 10.2152/jmi.56.209] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Chemical substances of foods drive the cognitive recognition of taste with the subsequent regulation of digestion in the gastrointestinal (GI) tract. Tastants like glutamate can bind to taste membrane receptors on the tip of specialized taste cells eliciting umami taste. In chemical-sensing cells diffused through the GI tract, glutamate induces functional changes. Most of the taste-like receptor-expressing cells from the stomach and intestine are neuroendocrine cells. The signaling molecules produced by these neuroendocrine cells either activate afferent nerve endings or release peptide hormones that can regulate neighboring cells in a paracrine fashion or travel through blood to their target receptor. Once afferent sensory fibers transfer the chemical information of the GI content to the central nervous system (CNS) facilitating the gut-brain signaling, the CNS regulates the GI through efferent cholinergic and noradrenergic fibers. Thus, this is a two-way extrinsic communication process. Glutamate within the lumen of the stomach stimulates afferent fibers and increases acid and pepsinogen release; whereas on the duodenum, glutamate increases the production of mucous to protect the mucosa against the incoming gastric acid. The effects of glutamate are believed to be mediated by G protein-coupled receptors expressed at the lumen of GI cells. The specific cell-type and molecular function of each of these receptors are not completely known. Here we will examine some of the glutamate receptors and their already understood role on GI function regulation.
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Affiliation(s)
- Ana San Gabriel
- Institute of Life Sciences, Ajinomoto Co., Inc., Kawasaki, Japan
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