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An alternative pathway for sweet sensation: possible mechanisms and physiological relevance. Pflugers Arch 2020; 472:1667-1691. [PMID: 33030576 DOI: 10.1007/s00424-020-02467-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/14/2020] [Accepted: 09/23/2020] [Indexed: 12/12/2022]
Abstract
Sweet substances are detected by taste-bud cells upon binding to the sweet-taste receptor, a T1R2/T1R3 heterodimeric G protein-coupled receptor. In addition, experiments with mouse models lacking the sweet-taste receptor or its downstream signaling components led to the proposal of a parallel "alternative pathway" that may serve as metabolic sensor and energy regulator. Indeed, these mice showed residual nerve responses and behavioral attraction to sugars and oligosaccharides but not to artificial sweeteners. In analogy to pancreatic β cells, such alternative mechanism, to sense glucose in sweet-sensitive taste cells, might involve glucose transporters and KATP channels. Their activation may induce depolarization-dependent Ca2+ signals and release of GLP-1, which binds to its receptors on intragemmal nerve fibers. Via unknown neuronal and/or endocrine mechanisms, this pathway may contribute to both, behavioral attraction and/or induction of cephalic-phase insulin release upon oral sweet stimulation. Here, we critically review the evidence for a parallel sweet-sensitive pathway, involved signaling mechanisms, neural processing, interactions with endocrine hormonal mechanisms, and its sensitivity to different stimuli. Finally, we propose its physiological role in detecting the energy content of food and preparing for digestion.
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General Decrease of Taste Sensitivity Is Related to Increase of BMI: A Simple Method to Monitor Eating Behavior. DISEASE MARKERS 2019; 2019:2978026. [PMID: 31089392 PMCID: PMC6476129 DOI: 10.1155/2019/2978026] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 02/13/2019] [Accepted: 02/28/2019] [Indexed: 12/12/2022]
Abstract
Background and Objectives The present study was conducted to evaluate the relationship between taste identification ability and body mass index (BMI) by studying the response to the administration of different taste stimuli to both sides of the tongue in three different groups of subjects. Subjects and Methods Thirty healthy normal-weight volunteers, 19 healthy overweight subjects, and 22 obese subjects were enrolled. For each subject, the lateralization Oldfield score, body weight, height, and blood pressure were determined. The taste test is based on filter paper strips soaked with 4 taste stimuli presented at different concentrations to evoke 4 basic taste qualities (salty, sour, sweet, and bitter); pure rapeseed oil and water were also administered to evoke fat and neutral taste qualities. The stimuli were applied to each side of the protruded tongue. Subjects were asked to identify the taste from a list of eight descriptions according to a multiple choice paradigm. Results The results showed a general lowering of taste sensitivity with the increase of BMI, except for the taste of fat with rapeseed oil as the stimulus. Other variables affecting taste sensitivity are age (negative association), gender (women generally show higher sensitivity), and taste stimuli concentration (positive association). Conclusions Our findings could provide important insights into how new therapies could be designed for weight loss and long-term weight maintenance and how diets could be planned combining the correct caloric and nutritional supply with individual taste preferences.
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3
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Sparks JT, Botsko G, Swale DR, Boland LM, Patel SS, Dickens JC. Membrane Proteins Mediating Reception and Transduction in Chemosensory Neurons in Mosquitoes. Front Physiol 2018; 9:1309. [PMID: 30294282 PMCID: PMC6158332 DOI: 10.3389/fphys.2018.01309] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/30/2018] [Indexed: 12/17/2022] Open
Abstract
Mosquitoes use chemical cues to modulate important behaviors such as feeding, mating, and egg laying. The primary chemosensory organs comprising the paired antennae, maxillary palps and labial palps are adorned with porous sensilla that house primary sensory neurons. Dendrites of these neurons provide an interface between the chemical environment and higher order neuronal processing. Diverse proteins located on outer membranes interact with chemicals, ions, and soluble proteins outside the cell and within the lumen of sensilla. Here, we review the repertoire of chemosensory receptors and other membrane proteins involved in transduction and discuss the outlook for their functional characterization. We also provide a brief overview of select ion channels, their role in mammalian taste, and potential involvement in mosquito taste. These chemosensory proteins represent targets for the disruption of harmful biting behavior and disease transmission by mosquito vectors.
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Affiliation(s)
- Jackson T Sparks
- Biology Department, High Point University, High Point, NC, United States
| | - Gina Botsko
- Biology Department, High Point University, High Point, NC, United States
| | - Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, United States
| | - Linda M Boland
- Department of Biology, University of Richmond, Richmond, VA, United States
| | - Shriraj S Patel
- Department of Biology, University of Richmond, Richmond, VA, United States
| | - Joseph C Dickens
- Department of Biology, University of Richmond, Richmond, VA, United States
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4
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Johnson RN, O'Meally D, Chen Z, Etherington GJ, Ho SYW, Nash WJ, Grueber CE, Cheng Y, Whittington CM, Dennison S, Peel E, Haerty W, O'Neill RJ, Colgan D, Russell TL, Alquezar-Planas DE, Attenbrow V, Bragg JG, Brandies PA, Chong AYY, Deakin JE, Di Palma F, Duda Z, Eldridge MDB, Ewart KM, Hogg CJ, Frankham GJ, Georges A, Gillett AK, Govendir M, Greenwood AD, Hayakawa T, Helgen KM, Hobbs M, Holleley CE, Heider TN, Jones EA, King A, Madden D, Graves JAM, Morris KM, Neaves LE, Patel HR, Polkinghorne A, Renfree MB, Robin C, Salinas R, Tsangaras K, Waters PD, Waters SA, Wright B, Wilkins MR, Timms P, Belov K. Adaptation and conservation insights from the koala genome. Nat Genet 2018; 50:1102-1111. [PMID: 29967444 PMCID: PMC6197426 DOI: 10.1038/s41588-018-0153-5] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 04/30/2018] [Indexed: 11/16/2022]
Abstract
The koala, the only extant species of the marsupial family Phascolarctidae, is classified as 'vulnerable' due to habitat loss and widespread disease. We sequenced the koala genome, producing a complete and contiguous marsupial reference genome, including centromeres. We reveal that the koala's ability to detoxify eucalypt foliage may be due to expansions within a cytochrome P450 gene family, and its ability to smell, taste and moderate ingestion of plant secondary metabolites may be due to expansions in the vomeronasal and taste receptors. We characterized novel lactation proteins that protect young in the pouch and annotated immune genes important for response to chlamydial disease. Historical demography showed a substantial population crash coincident with the decline of Australian megafauna, while contemporary populations had biogeographic boundaries and increased inbreeding in populations affected by historic translocations. We identified genetically diverse populations that require habitat corridors and instituting of translocation programs to aid the koala's survival in the wild.
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Affiliation(s)
- Rebecca N Johnson
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia.
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia.
| | - Denis O'Meally
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
- Animal Research Centre, Faculty of Science, Health, Education & Engineering, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Zhiliang Chen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | | | - Simon Y W Ho
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
| | - Will J Nash
- Earlham Institute, Norwich Research Park, Norwich, UK
| | - Catherine E Grueber
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
- San Diego Zoo Global, San Diego, CA, USA
| | - Yuanyuan Cheng
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
- UQ Genomics Initiative, University of Queensland, St Lucia, Queensland, Australia
| | - Camilla M Whittington
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
| | - Siobhan Dennison
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
| | - Emma Peel
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
| | | | - Rachel J O'Neill
- Department of Molecular and Cell Biology and Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | - Don Colgan
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
| | - Tonia L Russell
- Ramaciotti Centre for Genomics, University of New South Wales, Kensington, New South Wales, Australia
| | | | - Val Attenbrow
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
| | - Jason G Bragg
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- National Herbarium of New South Wales, Royal Botanic Gardens & Domain Trust, Sydney, New South Wales, Australia
| | - Parice A Brandies
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
| | - Amanda Yoon-Yee Chong
- Earlham Institute, Norwich Research Park, Norwich, UK
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Janine E Deakin
- Institute for Applied Ecology, University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Federica Di Palma
- Earlham Institute, Norwich Research Park, Norwich, UK
- Department of Biological Sciences, University of East Anglia, Norwich, UK
| | - Zachary Duda
- Department of Molecular and Cell Biology and Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | - Mark D B Eldridge
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
| | - Kyle M Ewart
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
| | - Carolyn J Hogg
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
| | - Greta J Frankham
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Amber K Gillett
- Australia Zoo Wildlife Hospital, Beerwah, Queensland, Australia
| | - Merran Govendir
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
| | - Alex D Greenwood
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
- Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Takashi Hayakawa
- Department of Wildlife Science (Nagoya Railroad Co., Ltd.), Primate Research Institute, Kyoto University, Inuyama, Japan
- Japan Monkey Centre, Inuyama, Japan
| | - Kristofer M Helgen
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
- School of Biological Sciences, Environment Institute, Centre for Applied Conservation Science, and ARC Centre of Excellence for Australian Biodiversity and Heritage, University of Adelaide, Adelaide, South Australia, Australia
| | - Matthew Hobbs
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
| | - Clare E Holleley
- Australian National Wildlife Collection, National Research Collections Australia, CSIRO, Canberra, Australian Capital Territory, Australia
| | - Thomas N Heider
- Department of Molecular and Cell Biology and Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | - Elizabeth A Jones
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
| | - Andrew King
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
| | - Danielle Madden
- Animal Research Centre, Faculty of Science, Health, Education & Engineering, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Jennifer A Marshall Graves
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- Institute for Applied Ecology, University of Canberra, Bruce, Australian Capital Territory, Australia
- School of Life Sciences, La Trobe University, Bundoora, Victoria, Australia
| | - Katrina M Morris
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Linda E Neaves
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
- Royal Botanic Garden Edinburgh, Edinburgh, UK
| | - Hardip R Patel
- John Curtin School of Medical Research, Australian National University, Acton, Australian Capital Territory, Australia
| | - Adam Polkinghorne
- Animal Research Centre, Faculty of Science, Health, Education & Engineering, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Marilyn B Renfree
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Charles Robin
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Ryan Salinas
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Kyriakos Tsangaras
- Department of Translational Genetics, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Paul D Waters
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Shafagh A Waters
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Belinda Wright
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
| | - Marc R Wilkins
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
- Ramaciotti Centre for Genomics, University of New South Wales, Kensington, New South Wales, Australia
| | - Peter Timms
- Faculty of Science, Health, Education & Engineering, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Katherine Belov
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, New South Wales, Australia
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Mast TG, Breza JM, Contreras RJ. Thirst Increases Chorda Tympani Responses to Sodium Chloride. Chem Senses 2017; 42:675-681. [PMID: 28981824 DOI: 10.1093/chemse/bjx052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In nature, water is present as a low-salt solution, thus we hypothesized that thirst would increase taste responses to low-salt solutions. We investigated the effect of thirst on the 2 different salt detection mechanisms present in the rat chorda tympani (CT) nerve. The first mechanism is dependent upon the epithelial sodium channel (ENaC), is blocked by benzamil, and is specific to the cation sodium. The second mechanism, while undefined, is independent of ENaC, and detects multiple cations. We expected thirst to increase benzamil-sensitive sodium responses due to mechanistically increasing the benzamil-sensitive ENaC. We recorded CT whole-nerve electrophysiological responses to lingual application of NaCl, KCl (30, 75, 150, 300, 500, and 600 mM), and imitation rainwater in both control and 24-h water-restricted male rats. NaCl solutions were presented in artificial saliva before and after lingual application of 5µM benzamil. Water restriction significantly increased the integrated CT responses to NaCl but not to KCl or imitation rainwater. Consistent with our hypothesis, only the benzamil-sensitive, and not the benzamil-insensitive, CT sodium response significantly increased. Additionally, CT responses to salt were recorded following induction of either osmotic or volemic thirst. Both thirsts significantly enhanced the integrated CT responses to NaCl and KCl, but not imitation rainwater. Interestingly, osmotic and volemic thirsts increased CT responses by increasing both the benzamil-sensitive and benzamil-insensitive CT sodium responses. We propose that thirst increases the sensitivity of the CT nerve to sodium.
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Affiliation(s)
- Thomas G Mast
- Department of Biology, Program in Neuroscience, Eastern Michigan University, Ypsilanti, MI 48197, USA.,Department of Psychology, Program in Neuroscience, Florida State University, 1107 West Call Street, Tallahassee, FL 30306, USA
| | - Joseph M Breza
- Department of Psychology, Program in Neuroscience, Florida State University, 1107 West Call Street, Tallahassee, FL 30306, USA.,Department of Psychology, Program in Neuroscience, Eastern Michigan University, Ypsilanti, MI 48197, USA
| | - Robert J Contreras
- Department of Psychology, Program in Neuroscience, Florida State University, 1107 West Call Street, Tallahassee, FL 30306, USA
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6
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DeSimone JA. The dependence of the phasic response of the taste nerves on stimulus flow rate arises in the diffusion boundary layer region at the lingual surface: A convective-diffusion analysis. Chem Eng Sci 2017. [DOI: 10.1016/j.ces.2017.04.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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7
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Qian J, Mummalaneni S, Phan THT, Heck GL, DeSimone JA, West D, Mahavadi S, Hojati D, Murthy KS, Rhyu MR, Spielman AI, Özdener MH, Lyall V. Cyclic-AMP regulates postnatal development of neural and behavioral responses to NaCl in rats. PLoS One 2017; 12:e0171335. [PMID: 28192441 PMCID: PMC5305205 DOI: 10.1371/journal.pone.0171335] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 01/18/2017] [Indexed: 02/07/2023] Open
Abstract
During postnatal development rats demonstrate an age-dependent increase in NaCl chorda tympani (CT) responses and the number of functional apical amiloride-sensitive epithelial Na+ channels (ENaCs) in salt sensing fungiform (FF) taste receptor cells (TRCs). Currently, the intracellular signals that regulate the postnatal development of salt taste have not been identified. We investigated the effect of cAMP, a downstream signal for arginine vasopressin (AVP) action, on the postnatal development of NaCl responses in 19-23 day old rats. ENaC-dependent NaCl CT responses were monitored after lingual application of 8-chlorophenylthio-cAMP (8-CPT-cAMP) under open-circuit conditions and under ±60 mV lingual voltage clamp. Behavioral responses were tested using 2 bottle/24h NaCl preference tests. The effect of [deamino-Cys1, D-Arg8]-vasopressin (dDAVP, a specific V2R agonist) was investigated on ENaC subunit trafficking in rat FF TRCs and on cAMP generation in cultured adult human FF taste cells (HBO cells). Our results show that in 19-23 day old rats, the ENaC-dependent maximum NaCl CT response was a saturating sigmoidal function of 8-CPT-cAMP concentration. 8-CPT-cAMP increased the voltage-sensitivity of the NaCl CT response and the apical Na+ response conductance. Intravenous injections of dDAVP increased ENaC expression and γ-ENaC trafficking from cytosolic compartment to the apical compartment in rat FF TRCs. In HBO cells dDAVP increased intracellular cAMP and cAMP increased trafficking of γ- and δ-ENaC from cytosolic compartment to the apical compartment 10 min post-cAMP treatment. Control 19-23 day old rats were indifferent to NaCl, but showed clear preference for appetitive NaCl concentrations after 8-CPT-cAMP treatment. Relative to adult rats, 14 day old rats demonstrated significantly less V2R antibody binding in circumvallate TRCs. We conclude that an age-dependent increase in V2R expression produces an AVP-induced incremental increase in cAMP that modulates the postnatal increase in TRC ENaC and the neural and behavioral responses to NaCl.
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Affiliation(s)
- Jie Qian
- Departments of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Shobha Mummalaneni
- Departments of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Tam-Hao T. Phan
- Departments of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Gerard L. Heck
- Departments of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - John A. DeSimone
- Departments of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - David West
- Departments of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Sunila Mahavadi
- Departments of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Deanna Hojati
- Departments of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Karnam S. Murthy
- Departments of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Mee-Ra Rhyu
- Korea Food Research Institute, Bundang-gu, Sungnam-si, Gyeonggi-do, Korea
| | | | - Mehmet Hakan Özdener
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
| | - Vijay Lyall
- Departments of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
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8
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Gleiser C, Wagner A, Fallier-Becker P, Wolburg H, Hirt B, Mack AF. Aquaporin-4 in Astroglial Cells in the CNS and Supporting Cells of Sensory Organs-A Comparative Perspective. Int J Mol Sci 2016; 17:E1411. [PMID: 27571065 PMCID: PMC5037691 DOI: 10.3390/ijms17091411] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 08/22/2016] [Accepted: 08/23/2016] [Indexed: 01/28/2023] Open
Abstract
The main water channel of the brain, aquaporin-4 (AQP4), is one of the classical water-specific aquaporins. It is expressed in many epithelial tissues in the basolateral membrane domain. It is present in the membranes of supporting cells in most sensory organs in a specifically adapted pattern: in the supporting cells of the olfactory mucosa, AQP4 occurs along the basolateral aspects, in mammalian retinal Müller cells it is highly polarized. In the cochlear epithelium of the inner ear, it is expressed basolaterally in some cells but strictly basally in others. Within the central nervous system, aquaporin-4 (AQP4) is expressed by cells of the astroglial family, more specifically, by astrocytes and ependymal cells. In the mammalian brain, AQP4 is located in high density in the membranes of astrocytic endfeet facing the pial surface and surrounding blood vessels. At these locations, AQP4 plays a role in the maintenance of ionic homeostasis and volume regulation. This highly polarized expression has not been observed in the brain of fish where astroglial cells have long processes and occur mostly as radial glial cells. In the brain of the zebrafish, AQP4 immunoreactivity is found along the radial extent of astroglial cells. This suggests that the polarized expression of AQP4 was not present at all stages of evolution. Thus, a polarized expression of AQP4 as part of a control mechanism for a stable ionic environment and water balanced occurred at several locations in supporting and glial cells during evolution. This initially basolateral membrane localization of AQP4 is shifted to highly polarized expression in astrocytic endfeet in the mammalian brain and serves as a part of the neurovascular unit to efficiently maintain homeostasis.
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Affiliation(s)
- Corinna Gleiser
- Institute of Clinical Anatomy and Cell Analysis, Eberhard Karls Universität Tübingen, 72074 Tübingen, Germany.
| | - Andreas Wagner
- Institute of Clinical Anatomy and Cell Analysis, Eberhard Karls Universität Tübingen, 72074 Tübingen, Germany.
| | - Petra Fallier-Becker
- Institute of Pathology and Neuropathology, Eberhard Karls Universität Tübingen, 72076 Tubingen, Germany.
| | - Hartwig Wolburg
- Institute of Pathology and Neuropathology, Eberhard Karls Universität Tübingen, 72076 Tubingen, Germany.
| | - Bernhard Hirt
- Institute of Clinical Anatomy and Cell Analysis, Eberhard Karls Universität Tübingen, 72074 Tübingen, Germany.
| | - Andreas F Mack
- Institute of Clinical Anatomy and Cell Analysis, Eberhard Karls Universität Tübingen, 72074 Tübingen, Germany.
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Water sensor ppk28 modulates Drosophila lifespan and physiology through AKH signaling. Proc Natl Acad Sci U S A 2014; 111:8137-42. [PMID: 24821805 DOI: 10.1073/pnas.1315461111] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Sensory perception modulates lifespan across taxa, presumably due to alterations in physiological homeostasis after central nervous system integration. The coordinating circuitry of this control, however, remains unknown. Here, we used the Drosophila melanogaster gustatory system to dissect one component of sensory regulation of aging. We found that loss of the critical water sensor, pickpocket 28 (ppk28), altered metabolic homeostasis to promote internal lipid and water stores and extended healthy lifespan. Additionally, loss of ppk28 increased neuronal glucagon-like adipokinetic hormone (AKH) signaling, and the AKH receptor was necessary for ppk28 mutant effects. Furthermore, activation of AKH-producing cells alone was sufficient to enhance longevity, suggesting that a perceived lack of water availability triggers a metabolic shift that promotes the production of metabolic water and increases lifespan via AKH signaling. This work provides an example of how discrete gustatory signals recruit nutrient-dependent endocrine systems to coordinate metabolic homeostasis, thereby influencing long-term health and aging.
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10
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Voigt N, Stein J, Galindo MM, Dunkel A, Raguse JD, Meyerhof W, Hofmann T, Behrens M. The role of lipolysis in human orosensory fat perception. J Lipid Res 2014; 55:870-82. [PMID: 24688103 DOI: 10.1194/jlr.m046029] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Taste perception elicited by food constituents and facilitated by sensory cells in the oral cavity is important for the survival of organisms. In addition to the five basic taste modalities, sweet, umami, bitter, sour, and salty, orosensory perception of stimuli such as fat constituents is intensely investigated. Experiments in rodents and humans suggest that free fatty acids represent a major stimulus for the perception of fat-containing food. However, the lipid fraction of foods mainly consists of triglycerides in which fatty acids are esterified with glycerol. Whereas effective lipolysis by secreted lipases (LIPs) liberating fatty acids from triglycerides in the rodent oral cavity is well established, a similar mechanism in humans is disputed. By psychophysical analyses of humans, we demonstrate responses upon stimulation with triglycerides which are attenuated by concomitant LIP inhibitor administration. Moreover, lipolytic activities detected in minor salivary gland secretions directly supplying gustatory papillae were correlated to individual sensitivities for triglycerides, suggesting that differential LIP levels may contribute to variant fat perception. Intriguingly, we found that the LIPF gene coding for lingual/gastric LIP is not expressed in human lingual tissue. Instead, we identified the expression of other LIPs, which may compensate for the absence of LIPF.
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Affiliation(s)
- Nadine Voigt
- Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke, 14558 Nuthetal, Germany
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11
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Mashiyama K, Nozawa Y, Ohtubo Y, Kumazawa T, Yoshii K. Time-dependent expression of hypertonic effects on bullfrog taste nerve responses to salts and bitter substances. Brain Res 2014; 1556:1-9. [PMID: 24513402 DOI: 10.1016/j.brainres.2014.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/27/2014] [Accepted: 02/04/2014] [Indexed: 10/25/2022]
Abstract
We previously showed that the hypertonicity of taste stimulating solutions modified tonic responses, the quasi-steady state component following the transient (phasic) component of each integrated taste nerve response. Here we show that the hypertonicity opens tight junctions surrounding taste receptor cells in a time-dependent manner and modifies whole taste nerve responses in bullfrogs. We increased the tonicity of stimulating solutions with non-taste substances such as urea or ethylene glycol. The hypertonicity enhanced phasic responses to NaCl>0.2M, and suppressed those to NaCl<0.1M, 1mM CaCl2, and 1mM bitter substances (quinine, denatonium and strychnine). The hypertonicity also enhanced the phasic responses to a variety of 0.5M salts such as LiCl and KCl. The enhancing effect was increased by increasing the difference between the ionic mobilities of the cations and anions in the salt. A preincubation time >20s in the presence of 1M non-taste substances was needed to elicit both the enhancing and suppressing effects. Lucifer Yellow CH, a paracellular marker dye, diffused into bullfrog taste receptor organs in 30s in the presence of hypertonicity. These results agreed with our proposed mechanism of hypertonic effects that considered the diffusion potential across open tight junctions.
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Affiliation(s)
- Kazunori Mashiyama
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Hibikino 2-4, Kitakyushu-shi 808-0196, Japan
| | - Yuhei Nozawa
- Department of Life Science and Green Chemistry, Saitama Institute of Technology, Fukaya 369-0293, Japan
| | - Yoshitaka Ohtubo
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Hibikino 2-4, Kitakyushu-shi 808-0196, Japan
| | - Takashi Kumazawa
- Graduate School of Engineering, Saitama Institute of Technology, Fukaya 369-0293, Japan
| | - Kiyonori Yoshii
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Hibikino 2-4, Kitakyushu-shi 808-0196, Japan.
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12
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Mack AF, Wolburg H. A novel look at astrocytes: aquaporins, ionic homeostasis, and the role of the microenvironment for regeneration in the CNS. Neuroscientist 2012; 19:195-207. [PMID: 22645111 DOI: 10.1177/1073858412447981] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aquaporin-4 (AQP4) water channels are located at the basolateral membrane domain of many epithelial cells involved in ion transport and secretion. These epithelial cells separate fluid compartments by forming apical tight junctions. In the brain, AQP4 is located on astrocytes in a polarized distribution: At the border to blood vessels or the pial surface, its density is very high. During ontogeny and phylogeny, astroglial cells go through a stage of expressing tight junctions, separating fluid compartments differently than in adult mammals. In adult mammals, this barrier is formed by arachnoid, choroid plexus, and endothelial cells. The ontogenetic and phylogenetic barrier transition from glial to endothelial cells correlates with the regenerative capacity of neuronal structures: Glial cells forming tight junctions, and expressing no or unpolarized AQP4 are found in the fish optic nerve and the olfactory nerve in mammals both known for their regenerative ability. It is hypothesized that highly polarized AQP4 expression and the lack of tight junctions on astrocytes increase ionic homeostasis, thus improving neuronal performance possibly at the expense of restraining neurogenesis and regeneration.
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Affiliation(s)
- Andreas F Mack
- Institute of Anatomy, University of Tübingen, Tübingen, Germany.
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13
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MacDonald CJ, Meck WH, Simon SA. Distinct neural ensembles in the rat gustatory cortex encode salt and water tastes. J Physiol 2012; 590:3169-84. [PMID: 22570382 DOI: 10.1113/jphysiol.2012.233486] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The gustatory cortex (GC) is important for perceiving the intensity of tastants but it remains unclear as to how single neurons in the region carry out this function. Previous studies have shown that taste-evoked activity from single neurons in GC can be correlated or anticorrelated with tastant concentration, yet whether one or both neural responses signal intensity is poorly characterized because animals from these studies were not trained to report the intensity of the concentration that they tasted. To address this issue, we designed a two-alternative forced choice (2-AFC) task in which freely licking rats distinguished among concentrations of NaCl and recorded from ensembles of neurons in the GC. We identified three neural ensembles that rapidly (<300 ms or ∼2 licks) processed NaCl concentration. For two ensembles, their NaCl evoked activity was anticorrelated with NaCl concentration but could be further distinguished by their response to water; in one ensemble, water evoked the greatest response while in the other ensemble the lowest tested NaCl concentration evoked the greatest response. However, the concentration sensitive activity from each of these ensembles did not show a strong association with the behaviour of the rat in the 2-AFC task, suggesting a lesser role for signalling tastant intensity. Conversely, for a third neural ensemble, its neural activity was well correlated with increases in NaCl concentration, and this relationship best matched the intensity perceived by the rat. These results suggest that this neuronal ensemble in GC whose activity monotonically increases with concentration plays an important role in signalling the intensity of the taste of NaCl.
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14
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Zichichi R, Magnoli D, Montalbano G, Laurà R, Vega JA, Ciriaco E, Germanà A. Aquaporin 4 in the sensory organs of adult zebrafish (Danio rerio). Brain Res 2011; 1384:23-8. [PMID: 21334314 DOI: 10.1016/j.brainres.2011.02.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 01/20/2011] [Accepted: 02/04/2011] [Indexed: 01/17/2023]
Abstract
The aquaporins (AQPs) are a family (AQP-AQP10) of transmembrane channel proteins that mediate the transport of water, ions, gases, and small molecules across the cell membrane, thus regulating cell homeostasis. AQP4 has the highest water permeability and it is involved in hearing and vision in mammals. Here, we used immunohistochemistry to map the presence of AQP4 in the sensory organs of adult zebrafish. The antibody used detected by Western blot proteins of 34 kDa (equivalent to that of mammalian AQP4) and maps in the sensory cells of taste buds, the hair sensory cells of the neuromast and of the maculae, and cristae ampullaris of the inner ear. Moreover, the retinal photoreceptors display AQP4 immunoreactivity. The non-sensory cells in these organs were AQP4 negative. These results suggest that the AQP4 could play a role in the regulation of water balance and ion transport in the sensory cells of zebrafish, bringing new data for the utilizing of this experimental model in the biology of sensory system.
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Affiliation(s)
- Rosalia Zichichi
- Dipartimento di Morfologia, Biochimica, Fisiologia e Produzione Animale, Sezione di Morfologia, Università di Messina, Messina, Italia
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15
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Kobayashi K, Yasui M. Cellular and subcellular localization of aquaporins 1, 3, 8, and 9 in amniotic membranes during pregnancy in mice. Cell Tissue Res 2010; 342:307-16. [DOI: 10.1007/s00441-010-1065-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 09/17/2010] [Indexed: 12/12/2022]
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16
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Rosen AM, Roussin AT, Di Lorenzo PM. Water as an independent taste modality. Front Neurosci 2010; 4:175. [PMID: 21048894 PMCID: PMC2967336 DOI: 10.3389/fnins.2010.00175] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 09/17/2010] [Indexed: 12/25/2022] Open
Abstract
To qualify as a "basic" taste quality or modality, defined as a group of chemicals that taste alike, three empirical benchmarks have commonly been used. The first is that a candidate group of tastants must have a dedicated transduction mechanism in the peripheral nervous system. The second is that the tastants evoke physiological responses in dedicated afferent taste nerves innervating the oropharyngeal cavity. Last, the taste stimuli evoke activity in central gustatory neurons, some of which may respond only to that group of tastants. Here we argue that water may also be an independent taste modality. This argument is based on the identification of a water dedicated transduction mechanism in the peripheral nervous system, water responsive fibers of the peripheral taste nerves and the observation of water responsive neurons in all gustatory regions within the central nervous system. We have described electrophysiological responses from single neurons in nucleus of the solitary tract (NTS) and parabrachial nucleus of the pons, respectively the first two central relay nuclei in the rodent brainstem, to water presented as a taste stimulus in anesthetized rats. Responses to water were in some cases as robust as responses to other taste qualities and sometimes occurred in the absence of responses to other tastants. Both excitatory and inhibitory responses were observed. Also, the temporal features of the water response resembled those of other taste responses. We argue that water may constitute an independent taste modality that is processed by dedicated neural channels at all levels of the gustatory neuraxis. Water-dedicated neurons in the brainstem may constitute key elements in the regulatory system for fluid in the body, i.e., thirst, and as part of the swallowing reflex circuitry.
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Affiliation(s)
- Andrew M Rosen
- Department of Psychology, Binghamton University Binghamton, NY, USA
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17
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Abstract
Taste buds are aggregates of 50–100 polarized neuroepithelial cells that detect nutrients and other compounds. Combined analyses of gene expression and cellular function reveal an elegant cellular organization within the taste bud. This review discusses the functional classes of taste cells, their cell biology, and current thinking on how taste information is transmitted to the brain.
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Affiliation(s)
- Nirupa Chaudhari
- Department of Physiology and Biophysics, and Program in Neurosciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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18
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Carleton A, Accolla R, Simon SA. Coding in the mammalian gustatory system. Trends Neurosci 2010; 33:326-34. [PMID: 20493563 DOI: 10.1016/j.tins.2010.04.002] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 03/29/2010] [Accepted: 04/13/2010] [Indexed: 01/17/2023]
Abstract
To understand gustatory physiology and associated dysfunctions it is important to know how oral taste stimuli are encoded both in the periphery and in taste-related brain centres. The identification of distinct taste receptors, together with electrophysiological recordings and behavioral assessments in response to taste stimuli, suggest that information about distinct taste modalities (e.g. sweet versus bitter) are transmitted from the periphery to the brain via segregated pathways. By contrast, gustatory neurons throughout the brain are more broadly tuned, indicating that ensembles of neurons encode taste qualities. Recent evidence reviewed here suggests that the coding of gustatory stimuli is not immutable, but is dependant on a variety of factors including appetite-regulating molecules and associative learning.
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Affiliation(s)
- Alan Carleton
- Department of Neurosciences, Medical Faculty, University of Geneva, 1 rue Michel-Servet, 1211 Genève 4, Switzerland.
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Devuyst O, Yool AJ. Aquaporin-1: New Developments and Perspectives for Peritoneal Dialysis. Perit Dial Int 2010; 30:135-41. [DOI: 10.3747/pdi.2010.00032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Peritoneal dialysis involves diffusive and convective transport and osmosis through the highly vascularized peritoneal membrane. Several lines of evidence have demonstrated that the water channel aquaporin-1 (AQP1) corresponds to the ultrasmall pore predicted by the model of peritoneal transport. Proof-of-principle studies have shown that upregulation of the expression of AQP1 in peritoneal capillaries results in increased water permeability and ultrafiltration, without affecting the osmotic gradient or small solute permeability. Conversely, studies in Aqp1 mice have shown that haplo-insufficiency for AQP1 results in significant attenuation of water transport. Recent studies have demonstrated that AQP1 is involved in the migration of different cell types, including endothelial cells. In parallel, chemical screening has identified lead compounds that could act as antagonists or agonists of AQPs, with description of putative binding sites and potential mechanisms of gating the water channel. By modulating water transport, these pharmacological agents could have clinically relevant effects in targeting specific tissues or disease states.
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Affiliation(s)
- Olivier Devuyst
- Division of Nephrology, School of Medical Sciences, University of Adelaide, Adelaide, Australia
| | - Andrea J. Yool
- Université catholique de Louvain Medical School, Brussels, Belgium; Discipline of Physiology, School of Medical Sciences, University of Adelaide, Adelaide, Australia
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Yool AJ, Brown EA, Flynn GA. Roles for novel pharmacological blockers of aquaporins in the treatment of brain oedema and cancer. Clin Exp Pharmacol Physiol 2009; 37:403-9. [PMID: 19566827 DOI: 10.1111/j.1440-1681.2009.05244.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
1. Aquaporins (AQPs) are targets for drug discovery for basic research and medicine. Human diseases involving fluid imbalances and oedema are of major concern and involve tissues in which AQPs are expressed. The range of functional properties of AQPs is continuing to expand steadily with ongoing research in the field. 2. Gating domains in AQPs are molecular sites for drug actions. Discovery of the arylsulphonamide AqB013 as an antagonist for AQP1 and AQP4 provided the first pharmacological agent with translational promise for the treatment of diseases in which AQPs have been implicated. The putative binding site for AqB013 in the internal vestibule of the AQP water pore involves amino acid residues that are located in the AQP loop D gating domain. 3. Aquaporins have been proposed as novel targets in cancer and oedema and are associated with a surprising array of important processes in the brain and body, such as angiogenesis, cell migration, development and neuropathological diseases. Functions beyond their simple role as water channels are suggested by the subtype-specific regulation of AQP expression. In both cancer and brain oedema, current therapies are limited and new pharmacological approaches focused on AQPs offer exciting potential for clinical advances.
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Affiliation(s)
- Andrea J Yool
- Discipline of Physiology, School of Molecular & Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia.
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Meunier N, Marion-Poll F, Lucas P. Water taste transduction pathway is calcium dependent in Drosophila. Chem Senses 2009; 34:441-9. [PMID: 19386695 DOI: 10.1093/chemse/bjp019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In mammals, detection of osmolarity by the gustatory system was overlooked until recently. In insects, specific taste receptor neurons detect hypoosmotic stimuli and are commonly called "W" (water) cells. W cells are easy to access in vivo and represent a good model to study the transduction of hypoosmotic stimuli. Using pharmacological and genetic approaches in Drosophila, we show that tarsal W cell firing activity depends on the concentration of external calcium bathing the dendrite. This dependence was confirmed by the strong inhibition of W cell responses to hypoosmotic stimuli by lanthanum (IC(50) = 8 nM), an ion known to inhibit calcium-permeable channels. Downstream, the transduction pathway likely involves calmodulin because calmodulin antagonists such as W-7 (IC(50) = 2 microM) and fluphenazine (IC(50) = 30 microM) prevented the activation of the W cell by hypoosmotic stimuli. A protein kinase C (PKC) may also be involved as W cell responses were blocked by PKC inhibitors, chelerythrine (IC(50) = 20 microM) and staurosporine (IC(50) = 30 microM). It was also reduced when expressing an inhibitory pseudosubstrate of PKC in gustatory receptor neurons. In the rat, the transduction pathway underlying low osmolarity detection involves aquaporin and swelling-activated ion channels. Our study suggests that the transduction pathway of hypoosmotic stimuli in insects differs from mammals.
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Affiliation(s)
- Nicolas Meunier
- Institut National de Recherche Agronomique, Unité Mixte de Recherche, 1272 Physiologie de l'Insecte-Signalisation et Communication, Versailles, France.
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Merigo F, Benati D, Galie M, Crescimanno C, Osculati F, Sbarbati A. Immunohistochemical Localization of Cystic Fibrosis Transmembrane Regulator and Clara Cell Secretory Protein in Taste Receptor Cells of Rat Circumvallate Papillae. Chem Senses 2007; 33:231-41. [DOI: 10.1093/chemse/bjm082] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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