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Dual skin functions in amphibian osmoregulation. Comp Biochem Physiol A Mol Integr Physiol 2021; 253:110869. [DOI: 10.1016/j.cbpa.2020.110869] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/07/2020] [Accepted: 12/07/2020] [Indexed: 12/11/2022]
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Larsen EH, Sørensen JN. Stationary and Nonstationary Ion and Water Flux Interactions in Kidney Proximal Tubule: Mathematical Analysis of Isosmotic Transport by a Minimalistic Model. Rev Physiol Biochem Pharmacol 2019; 177:101-147. [DOI: 10.1007/112_2019_16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
AbstractOur mathematical model of epithelial transport (Larsen et al. Acta Physiol. 195:171–186, 2009) is extended by equations for currents and conductance of apical SGLT2. With independent variables of the physiological parameter space, the model reproduces intracellular solute concentrations, ion and water fluxes, and electrophysiology of proximal convoluted tubule. The following were shown:Water flux is given by active Na+flux into lateral spaces, while osmolarity of absorbed fluid depends on osmotic permeability of apical membranes.Following aquaporin “knock-out,” water uptake is not reduced but redirected to the paracellular pathway.Reported decrease in epithelial water uptake in aquaporin-1 knock-out mouse is caused by downregulation of active Na+absorption.Luminal glucose stimulates Na+uptake by instantaneous depolarization-induced pump activity (“cross-talk”) and delayed stimulation because of slow rise in intracellular [Na+].Rate of fluid absorption and flux of active K+absorption would have to be attuned at epithelial cell level for the [K+] of the absorbate being in the physiological range of interstitial [K+].Following unilateral osmotic perturbation, time course of water fluxes between intraepithelial compartments provides physical explanation for the transepithelial osmotic permeability being orders of magnitude smaller than cell membranes’ osmotic permeability.Fluid absorption is always hyperosmotic to bath.Deviation from isosmotic absorption is increased in presence of glucose contrasting experimental studies showing isosmotic transport being independent of glucose uptake.For achieving isosmotic transport, the cost of Na+recirculation is predicted to be but a few percent of the energy consumption of Na+/K+pumps.
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Chammas SM, Carneiro SM, Ferro RS, Antoniazzi MM, Jared C. Development of integument and cutaneous glands in larval, juvenile and adult toads (Rhinella granulosa): a morphological and morphometric study. ACTA ZOOL-STOCKHOLM 2014. [DOI: 10.1111/azo.12091] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Sérgio M. Chammas
- Laboratory of Cellular Biology; Instituto Butantan; Avenida Vital Brasil 1500 CEP 05503-000 São Paulo São Paulo Brazil
| | - Sylvia M. Carneiro
- Laboratory of Cellular Biology; Instituto Butantan; Avenida Vital Brasil 1500 CEP 05503-000 São Paulo São Paulo Brazil
| | - Rafael S. Ferro
- Laboratory of Cellular Biology; Instituto Butantan; Avenida Vital Brasil 1500 CEP 05503-000 São Paulo São Paulo Brazil
| | - Marta M. Antoniazzi
- Laboratory of Cellular Biology; Instituto Butantan; Avenida Vital Brasil 1500 CEP 05503-000 São Paulo São Paulo Brazil
| | - Carlos Jared
- Laboratory of Cellular Biology; Instituto Butantan; Avenida Vital Brasil 1500 CEP 05503-000 São Paulo São Paulo Brazil
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Larsen EH, Deaton LE, Onken H, O'Donnell M, Grosell M, Dantzler WH, Weihrauch D. Osmoregulation and Excretion. Compr Physiol 2014; 4:405-573. [DOI: 10.1002/cphy.c130004] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Grubb S, Poulsen KA, Juul CA, Kyed T, Klausen TK, Larsen EH, Hoffmann EK. TMEM16F (Anoctamin 6), an anion channel of delayed Ca(2+) activation. ACTA ACUST UNITED AC 2014; 141:585-600. [PMID: 23630341 PMCID: PMC3639583 DOI: 10.1085/jgp.201210861] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Members of the TMEM16 (Anoctamin) family of membrane proteins have been shown to be essential constituents of the Ca2+-activated Cl− channel (CaCC) in many cell types. In this study, we have investigated the electrophysiological properties of mouse TMEM16F. Heterologous expression of TMEM16F in HEK293 cells resulted in plasma membrane localization and an outwardly rectifying ICl,Ca that was activated with a delay of several minutes. Furthermore, a significant Na+ current was activated, and the two permeabilities were correlated according to PNa = 0.3 PCl. The current showed an EC50 of 100 µM intracellular free Ca2+ concentration and an Eisenman type 1 anion selectivity sequence of PSCN > PI > PBr > PCl > PAsp. The mTMEM16F-associated ICl,Ca was abolished in one mutant of the putative pore region (R592E) but retained in two other mutants (K616E and R636E). The mutant K616E had a lower relative permeability to iodide, and the mutant R636E had an altered anion selectivity sequence (PSCN = PI = PBr = PCl > PAsp). Our data provide evidence that TMEM16F constitutes a Ca2+-activated anion channel or a pore-forming subunit of an anion channel with properties distinct from TMEM16A.
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Affiliation(s)
- Søren Grubb
- Department of Biology, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
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Haslam IS, Roubos EW, Mangoni ML, Yoshizato K, Vaudry H, Kloepper JE, Pattwell DM, Maderson PFA, Paus R. From frog integument to human skin: dermatological perspectives from frog skin biology. Biol Rev Camb Philos Soc 2013; 89:618-55. [DOI: 10.1111/brv.12072] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 10/03/2013] [Accepted: 10/22/2013] [Indexed: 12/15/2022]
Affiliation(s)
- Iain S. Haslam
- The Dermatology Centre, Salford Royal NHS Foundation Trust, Institute of Inflammation and Repair; University of Manchester; Oxford Road Manchester M13 9PT U.K
| | - Eric W. Roubos
- Department of Anatomy; Radboud University Medical Centre; Geert Grooteplein Noord 2, 6525 EZ, Nijmegen P.O. Box 9101, 6500 HB Nijmegen The Netherlands
| | - Maria Luisa Mangoni
- Department of Biochemical Sciences, Istituto Pasteur-Fondazione Cenci Bolognetti; La Sapienza University of Rome, Piazzale Aldo Moro, 5-00185; Rome Italy
| | - Katsutoshi Yoshizato
- Academic Advisors Office, Synthetic Biology Research Center; Osaka City University Graduate School of Medicine; Osaka Japan
- Phoenixbio Co. Ltd; 3-4-1, Kagamiyama; Higashihiroshima Hiroshima 739-0046 Japan
| | - Hubert Vaudry
- European Institute for Peptide Research; University of Rouen; Mont-Saint-Aignan Place Emile Blondel 76821 France
- INSERM U-982, CNRS; University of Rouen; Mont-Saint-Aignan Place Emile Blondel 76821 France
| | - Jennifer E. Kloepper
- Klinik für Dermatologie, Allergologie und Venerologie; Universitätsklinikum Schleswig-Holstein, Ratzeburger Allee 160; 23538 Lübeck Germany
| | - David M. Pattwell
- Leahurst Campus, Institute of Learning & Teaching; School of Veterinary Science, University of Liverpool; Neston CH64 7TE U.K
| | | | - Ralf Paus
- The Dermatology Centre, Salford Royal NHS Foundation Trust, Institute of Inflammation and Repair; University of Manchester; Oxford Road Manchester M13 9PT U.K
- Klinik für Dermatologie, Allergologie und Venerologie; Universitätsklinikum Schleswig-Holstein, Ratzeburger Allee 160; 23538 Lübeck Germany
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Cruz MJ, Sourial MM, Treberg JR, Fehsenfeld S, Adlimoghaddam A, Weihrauch D. Cutaneous nitrogen excretion in the African clawed frog Xenopus laevis: effects of high environmental ammonia (HEA). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 136-137:1-12. [PMID: 23624175 DOI: 10.1016/j.aquatox.2013.03.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 03/05/2013] [Accepted: 03/12/2013] [Indexed: 06/02/2023]
Abstract
Ammonia is a highly toxic molecule and often introduced in considerable amounts into aquatic environments due to anthropogenic activities. Many aquatic and semi-aquatic amphibians utilize, in addition to their kidneys, the skin for osmoregulation and nitrogen excretion. In the present study the effects of prolonged (7-21 days) exposure to high environmental ammonia (HEA, 1 mmol l(-1) NH4Cl) on cutaneous nitrogen excretion and gene expression of key-transporters involved in nitrogen excretion and acid-base regulation were investigated in the fully aquatic African clawed frog, Xenopus laevis. The study revealed that X. laevis excretes predominately ammonia of which approximately 50% is excreted via the skin. Both the ventral and dorsal skin were capable to generate a net ammonia efflux, which was significantly activated by 10 mmol l(-1) of the phosphodiesterase blocker theophylline. The obtained data further suggest that the ammonia efflux was promoted by an acidification of the unstirred boundary layer, likely generated by an apical localized V-ATPase, with NH3 being transported via cutaneous expressed ammonia transporters, Rhbg and Rhcg. Prolonged HEA exposure did significantly reduce the net-flux rates over the ventral skin with Vmax changing from 256 nmol cm(-2) h(-1) in control frogs to 196 nmol cm(-2) h(-1) in HEA exposed animals. Further, prolonged HEA exposure caused a decrease in mRNA expression levels of the ammonia transporter Rhbg, Na(+)/K(+)-ATPase (α-subunit) and V-ATPase (subunit H) in the ventral and dorsal skin and the kidney. In contrast, Rhcg expression levels were unaffected by HEA in skin tissues.
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Affiliation(s)
- Melissa J Cruz
- Biology Faculty, University of British Columbia, Kelowna, BC V1V 1V7, Canada
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Larsen EH, Ramløv H. Role of cutaneous surface fluid in frog osmoregulation. Comp Biochem Physiol A Mol Integr Physiol 2013; 165:365-70. [PMID: 23587876 DOI: 10.1016/j.cbpa.2013.04.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 04/05/2013] [Accepted: 04/08/2013] [Indexed: 02/04/2023]
Abstract
The study investigated whether evaporative water loss (EWL) in frogs stems from water diffusing through the skin or fluid secreted by mucous glands. Osmolality of cutaneous surface fluid (CSF) of Rana esculenta (Pelophylax kl. esculentus) subjected to isoproterenol or 30°C-34°C was 191±9.3 and 181±7.5 mosm/kg, respectively, as compared to lymph osmolality of, 249±10 mosm/kg. Cation concentrations of CSF were likewise independent of pre-treatment with averages of, [Na(+)]=65.5±5.1 and [K(+)]=14.9±1.6 mmol/L, and lymph concentrations of 116 mmol Na(+)/L and 5.1 mmol K(+)/L. The relatively high [K(+)] confirms that CSF is produced by submucosal glands. Since the chemical energy of water of CSF was always higher than that of body fluids, diffusion of water would be from CSF to the interstitial fluid and not in the opposite direction. It is concluded that volume and composition of CSF are regulated by subepidermal exocrine gland secretion balanced by EWL into the atmosphere and ion reuptake by the epidermal epithelium. Previously discovered regulatory mechanisms of epithelial ion absorption, hitherto not ascribed a body function, fit well with a role in regulating turnover of CSF. As a regulated external physiological compartment, CSF would be of importance for the immune defenses that amphibians employ in protecting their skin.
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Affiliation(s)
- Erik Hviid Larsen
- Department of Biology, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark.
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Persson PB, Persson AB. A matter of taste. Acta Physiol (Oxf) 2013; 207:203-5. [PMID: 23297704 DOI: 10.1111/apha.12023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- P B Persson
- Institute of Vegetative Physiology, Charité-Universitaetsmedizin Berlin, Berlin, Germany
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Affiliation(s)
- P. B. Persson
- Institut of Vegetative Physiology; Charité Universitaetsmedizin Berlin; Berlin; Germany
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Campbell CR, Voyles J, Cook DI, Dinudom A. Frog skin epithelium: electrolyte transport and chytridiomycosis. Int J Biochem Cell Biol 2011; 44:431-4. [PMID: 22182598 DOI: 10.1016/j.biocel.2011.12.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 11/23/2011] [Accepted: 12/02/2011] [Indexed: 11/16/2022]
Abstract
One unique physiological characteristic of frogs is that their main route for intake of water is across the skin. In these animals, the skin acts in concert with the kidney and urinary bladder to maintain electrolyte homeostasis. Water absorption across the skin is driven by the osmotic gradient that develops as a consequence of solute transport. Our recent study demonstrated that chytridiomycosis, an infection of amphibian skin by the fungal pathogen, Batrachochytrium dendrobatidis, inhibits epithelial Na(+) channels, attenuating Na(+) absorption through the skin. In frogs that become severely affected by this fungus, systemic depletion of Na(+), K(+) and Cl(-) is thought to cause deterioration of cardiac electrical function, leading to cardiac arrest. Here we review the ion transport mechanisms of frog skin, and discuss the effect of chytridiomycosis on these mechanisms.
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Affiliation(s)
- Craig R Campbell
- Discipline of Physiology, Sydney Medical School and Bosch Institute, The University of Sydney, New South Wales 2006, Australia
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