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Blazer-Yost BL. Following Ussing's legacy: from amphibian models to mammalian kidney and brain. Am J Physiol Cell Physiol 2022; 323:C1061-C1069. [PMID: 36036449 PMCID: PMC9529261 DOI: 10.1152/ajpcell.00303.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 11/22/2022]
Abstract
Professor Hans H. Ussing (1911-2000) was one of the founding members of the field of epithelial cell biology. He is most famous for the electrophysiological technique that he developed to measure electrogenic ion flux across epithelial tissues. Ussing-style electrophysiology has been applied to multiple tissues and has informed fields as diverse as amphibian biology and medicine. In the latter, this technique has contributed to a basic understanding of maladies such as hypertension, polycystic kidney disease, cystic fibrosis, and diarrheal diseases to mention but a few. In addition to this valuable contribution to biological methods, Prof. Ussing also provided strong evidence for the concept of active transport several years before the elucidation of Na+K+ATPase. In addition, he provided cell biologists with the important concept of polarized epithelia with specific and different transporters found in the apical and basolateral membranes, thus providing these cells with the ability to conduct directional, active and passive transepithelial transport. My studies have used Ussing chamber electrophysiology to study the toad urinary bladder, an amphibian cell line, renal cell lines, and, most recently, choroid plexus cell lines. This technique has formed the basis of our in vitro mechanistic studies that are used in an iterative manner with animal models to better understand disease progress and treatment. I was honored to be invited to deliver the 2022 Hans Ussing Lecture sponsored by the Epithelial Transport Group of the American Physiological Society. This manuscript is a version of the material presented in that lecture.
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Affiliation(s)
- Bonnie L Blazer-Yost
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana
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Larsen EH, Hoffmann E, Hedrick MS, Wang T. August Krogh's contribution to the rise of physiology during the first half the 20th century. Comp Biochem Physiol A Mol Integr Physiol 2021; 256:110931. [DOI: 10.1016/j.cbpa.2021.110931] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a common genetic disorder characterized by bilateral fluid-filled cysts, renal inflammation and extensive fibrosis, leading to the progressive decline in kidney function. Renal cyst formation begins in utero from aberrant proliferation of tubule epithelial cells; however, the mechanisms for cystogenesis remain unclear. Cell proliferation and Cl--dependent fluid secretion, which drives the accumulation of cyst fluid, are responsible for inexorable growth of cysts and the remarkable appearance of massively enlarged ADPKD kidneys. Investigators have used in vitro assays to explore cellular and molecular mechanisms involved in ADPKD cyst epithelial cell proliferation and Cl--dependent fluid secretion in experimentally controlled environments. These assays have been used to evaluate potential therapeutic approaches to inhibit cellular pathways involved in cyst growth. This chapter discusses methods for measuring ADPKD cell proliferation, transepithelial Cl- secretion, and net fluid transport across cyst epithelial cell monolayers.
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Affiliation(s)
- Gail A Reif
- Departments of Internal Medicine and Molecular and Integrative Physiology, and The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Darren P Wallace
- Departments of Internal Medicine and Molecular and Integrative Physiology, and The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States.
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Lallès JP. Biology, environmental and nutritional modulation of skin mucus alkaline phosphatase in fish: A review. FISH & SHELLFISH IMMUNOLOGY 2019; 89:179-186. [PMID: 30928666 DOI: 10.1016/j.fsi.2019.03.053] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/15/2019] [Accepted: 03/25/2019] [Indexed: 06/09/2023]
Abstract
Alkaline phosphatase (AP) is a major, recently recognized component of innate immunity. The intestinal AP (IAP) isoform plays a pivotal role in controlling gastrointestinal and systemic inflammation in terrestrial mammals. This is so essentially through detoxification (by dephosphorylation) of proinflammatory microbial components that can no longer be recognized by so-called toll-like receptors, thus preventing cellular inflammatory cascade activation. A unique feature of fish is the presence of AP in skin and epidermal mucus (skin mucus AP) but its actual functions and underlying mechanisms of action are presently unknown. Here, we gather and analyse knowledge available on skin mucus AP in order to provide a holistic view of this important protective enzyme. Our main conclusions are that skin mucus AP is responsive to biotic and abiotic factors, including nutrients and bioactive feed components, prebiotics and probiotics. Importantly, both skin mucus AP and IAP appear to correlate, thus raising the interesting possibility that skin mucus AP be used as a proxy for IAP in future nutritional studies. Blood serum AP also seems to correlate with skin mucus AP, though biological interpretation for such relationship is presently unknown. Finally, the precise isoform/s of AP present in skin should be identified and underlying molecular mechanisms of skin mucus AP actions deciphered.
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Nichols JW, Sakurai Y, Harashima H, Bae YH. Nano-sized drug carriers: Extravasation, intratumoral distribution, and their modeling. J Control Release 2017; 267:31-46. [DOI: 10.1016/j.jconrel.2017.08.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/25/2017] [Accepted: 08/01/2017] [Indexed: 01/02/2023]
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Measurement of ion fluxes across epithelia. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 127:1-11. [DOI: 10.1016/j.pbiomolbio.2017.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 03/13/2017] [Accepted: 03/18/2017] [Indexed: 12/23/2022]
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7
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Lucu Č, Ziegler A. The effects of hypoxia on active ionic transport processes in the gill epithelium of hyperregulating crab, Carcinus maneas. Comp Biochem Physiol A Mol Integr Physiol 2017. [PMID: 28629793 DOI: 10.1016/j.cbpa.2017.06.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Effects of hypoxia on the osmorespiratory functions of the posterior gills of the shore crab Carcinus maenas acclimated to 12ppt seawater (DSW) were studied. Short-circuit current (Isc) across the hemilamella (one epithelium layer supported by cuticle) was substantially reduced under exposure to 1.6, 2.0, or 2.5mg O2/L hypoxic saline (both sides of epithelium) and fully recovered after reoxygenation. Isc was reduced equally in the epithelium exposed to 1.6mg O2/L on both sides and when the apical side was oxygenated and the basolateral side solely exposed to hypoxia. Under 1.6mg O2/L, at the level of maximum inhibition of Isc, conductance was decreased from 40.0mScm-2 to 34.7mScm-2 and fully recovered after reoxygenation. Isc inhibition under hypoxia and reduced 86Rb+ (K+) fluxes across apically located K+ channels were caused preferentially by reversible inhibition of basolaterally located and ouabain sensitive Na+,K+-ATPase mediated electrogenic transport. Reversible inhibition of Isc is discussed as decline in active transport energy supply down regulating metabolic processes and saving energy during oxygen deprivation. In response to a 4day exposure of Carcinus to 2.0mg O2/L, hemolymph Na+ and Cl- concentration decreased, i.e. hyperosmoregulation was weakened. Variations of the oxygen concentration level and exposure time to hypoxia lead to an increase of the surface of mitochondria per epithelium area and might in part compensate for the decrease in oxygen availability under hypoxic conditions.
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Affiliation(s)
- Čedomil Lucu
- Alfred Wegener- Institute Helmholtz Center for Polar and Marine Research Wadden Sea Station/List/Sylt, Germany; Institute Ruđer Bošković, Center for Marine Research Rovinj, Zagreb, Croatia.
| | - Andreas Ziegler
- Central Facility for Electron Microscopy University of Ulm, A. Einstein Alee 11, 89069 Ulm, Germany
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Stanton BA. Effects of Pseudomonas aeruginosa on CFTR chloride secretion and the host immune response. Am J Physiol Cell Physiol 2017; 312:C357-C366. [PMID: 28122735 DOI: 10.1152/ajpcell.00373.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 01/20/2017] [Accepted: 01/21/2017] [Indexed: 12/18/2022]
Abstract
In the healthy lung the opportunistic pathogen, Pseudomonas aeruginosa, is rapidly eliminated by mucociliary clearance, a process that is dependent on the activity of the CFTR anion channel that, in concert with a number of other transport proteins, regulates the volume and composition of the periciliary surface liquid. This fluid layer is essential to enable cilia to clear pathogens from the lungs. However, in cystic fibrosis (CF), mutations in the CFTR gene reduce Cl- and [Formula: see text] secretion, thereby decreasing periciliary surface liquid volume and mucociliary clearance of bacteria. In CF this leads to persistent infection with the opportunistic pathogen, P. aeruginosa, which is the cause of reduced lung function and death in ~95% of CF patients. Others and we have conducted studies to elucidate the effects of P. aeruginosa on wild-type and Phe508del-CFTR Cl- secretion as well as on the host immune response. These studies have demonstrated that Cif (CFTR inhibitory factor), a virulence factor secreted by P. aeruginosa, is associated with reduced lung function in CF and induces the ubiquitination and degradation of wt-CFTR as well as TAP1, which plays a key role in viral and bacterial antigen presentation. Cif also enhances the degradation of Phe508del-CFTR that has been rescued by ORKAMBI, a drug approved for CF patients homozygous for the Phe508del-CFTR mutation, thereby reducing drug efficacy. This review is based on the Hans Ussing Distinguished Lecture at the 2016 Experimental Biology Meeting given by the author.
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Affiliation(s)
- Bruce A Stanton
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
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Net Fluorescein Flux Across Corneal Endothelium Strongly Suggests Fluid Transport is due to Electro-osmosis. J Membr Biol 2016; 249:469-73. [PMID: 26989056 PMCID: PMC4942490 DOI: 10.1007/s00232-016-9887-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/09/2016] [Indexed: 11/04/2022]
Abstract
We have presented prior evidence suggesting that fluid transport results from electro-osmosis at the intercellular junctions of the corneal endothelium. Such phenomenon ought to drag other extracellular solutes. We have investigated this using fluorescein-Na2 as an extracellular marker. We measured unidirectional fluxes across layers of cultured human corneal endothelial (HCE) cells. SV-40-transformed HCE layers were grown to confluence on permeable membrane inserts. The medium was DMEM with high glucose and no phenol red. Fluorescein-labeled medium was placed either on the basolateral or the apical side of the inserts; the other side carried unlabeled medium. The inserts were held in a CO2 incubator for 1 h (at 37 °C), after which the entire volume of the unlabeled side was collected. After that, label was placed on the opposite side, and the corresponding paired sample was collected after another hour. Fluorescein counts were determined with a (Photon Technology) DeltaScan fluorometer (excitation 380 nm; emission 550 nm; 2 nm bwth). Samples were read for 60 s. The cells utilized are known to transport fluid from the basolateral to the apical side, just as they do in vivo in several species. We used 4 inserts for influx and efflux (total: 20 1-h periods). We found a net flux of fluorescein from the basolateral to the apical side. The flux ratio was 1.104 ± 0.056. That difference was statistically significant (p = 0.00006, t test, paired samples). The endothelium has a definite restriction at the junctions. Hence, an asymmetry in unidirectional fluxes cannot arise from osmosis, and can only point instead to paracellular solvent drag. We suggest, once more, that such drag is due to electro-osmotic coupling at the paracellular junctions.
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McDermott FD, Folan DMA, Winter DC, Folan MA, Baird AW. Gnotobiotic Human Colon Ex Vivo. Gastroenterology Res 2015; 8:247-252. [PMID: 27785304 PMCID: PMC5051042 DOI: 10.14740/gr675w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/20/2015] [Indexed: 01/17/2023] Open
Abstract
Background A novel emulsion with efficacy as an agent for eliminating biofilms was selected. The aim of this study was to examine efficacy and effect of a formulation of ML:8 against commensal bacteria harvested from ex vivo human colonic tissues. Methods Mucosal sheets, obtained at the time of surgery, were exposed for 2 minutes to one of four solutions: Krebs-Hensleit (KH) solution, saline (NaCl; 0.9%), povidone iodine (1%), or ML:8 (2%); n = 4. Lumenal surfaces were swabbed for culture under aerobic or anaerobic conditions. Following treatment, each sheet was mounted in Ussing chambers and voltage clamped. Tissues were challenged with carbachol. Permeability coefficient (Papp) was determined using mannitol fluxes. At the end of each experiment, tissues were examined histologically. Results Similar colony forming units grew in aerobic and anaerobic conditions in both control and NaCl treated tissues. Iodine reduced and ML:8 virtually abolished viable bacteria. Basal electrophysiological parameters were not different between treatments. Transepithelial electrical resistance values did not differ between groups. All tissues responded to carbachol, although this was attenuated in iodine treated tissue. Papp values were slightly elevated in all treated tissues but this did not reach significance. Histopathological assessment revealed no overt damage to tissues. Conclusion Brief exposure to ML:8 reduced culturable bacterial burden from human intestinal tissues harvested at the time of surgical resection. Such gnotobiotic tissues retain structural and functional integrity. This is a novel approach to reduce bacterial burden.
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Affiliation(s)
- Frank D McDermott
- UCD School of Veterinary Medicine & Conway Institute of Biomolecular & Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland; UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland; These authors contributed equally to the study
| | - David M A Folan
- UCD School of Veterinary Medicine & Conway Institute of Biomolecular & Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland; These authors contributed equally to the study
| | - Des C Winter
- UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland; Department of Surgery, St Vincent's University Hospital, Elm Park, Dublin 4, Ireland
| | - Michael A Folan
- UCD School of Veterinary Medicine & Conway Institute of Biomolecular & Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Alan W Baird
- UCD School of Veterinary Medicine & Conway Institute of Biomolecular & Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
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Cacace V, Kusnier CF, Fischbarg J. RETRACTED ARTICLE: Net Fluorescein Flux Across Corneal Endothelium Suggests Fluid Transport is Driven by Electroosmosis. J Membr Biol 2015; 249:197. [PMID: 26423751 PMCID: PMC4851691 DOI: 10.1007/s00232-015-9849-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 09/18/2015] [Indexed: 11/30/2022]
Affiliation(s)
- V Cacace
- ININCA, Conicet, Marcelo T. de Alvear 2270, CP 1122AAJ, Buenos Aires, Argentina
| | - C F Kusnier
- ININCA, Conicet, Marcelo T. de Alvear 2270, CP 1122AAJ, Buenos Aires, Argentina
| | - J Fischbarg
- ININCA, Conicet, Marcelo T. de Alvear 2270, CP 1122AAJ, Buenos Aires, Argentina.
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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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Lomasney KW, Hyland NP. The application of Ussing chambers for determining the impact of microbes and probiotics on intestinal ion transport. Can J Physiol Pharmacol 2013; 91:663-70. [DOI: 10.1139/cjpp-2013-0027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Host–microbe interactions have gained considerable attention in recent years with regards to their role in various organic disorders and diseases. In particular, research efforts have focused on the intestinal microbiota, where the largest and most diverse populations not only co-exist with the host, but also directly influence the state and function of the gastrointestinal (GI) tract. Moreover, both human and animal studies alike are now beginning to show a positive influence of probiotic bacteria on GI disorders associated with diarrhoea or constipation. Diarrheagenic GI diseases, such as those caused by Vibreo cholera or enterpathogenic Eschericia coli, have well-characterised interactions with the host that explain much of the observed symptoms, in particular severe diarrhoea. However, the mechanisms of action of nonpathogenic bacteria or probiotics on host physiology are less clearly understood. In the context of defining the mechanisms of action of probiotics in vitro, the Ussing chamber has proven to be a particularly useful tool. Here, we will present data from several studies that have defined molecular targets for microbes and putative probiotics in the regulation of intestinal secretory and absorptive function, and we will discuss these in the context of their application in pathogen- or inflammation-induced alterations in intestinal ion transport.
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Affiliation(s)
- Kevin W. Lomasney
- Department of Pharmacology and Therapeutics, Western Gateway Building, Western Road, University College Cork, Co. Cork, Ireland
- Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Co. Cork, Ireland
| | - Niall P. Hyland
- Department of Pharmacology and Therapeutics, Western Gateway Building, Western Road, University College Cork, Co. Cork, Ireland
- Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Co. Cork, Ireland
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Frizzell RA, Hanrahan JW. Physiology of epithelial chloride and fluid secretion. Cold Spring Harb Perspect Med 2013; 2:a009563. [PMID: 22675668 DOI: 10.1101/cshperspect.a009563] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Epithelial salt and water secretion serves a variety of functions in different organ systems, such as the airways, intestines, pancreas, and salivary glands. In cystic fibrosis (CF), the volume and/or composition of secreted luminal fluids are compromised owing to mutations in the gene encoding CFTR, the apical membrane anion channel that is responsible for salt secretion in response to cAMP/PKA stimulation. This article examines CFTR and related cellular transport processes that underlie epithelial anion and fluid secretion, their regulation, and how these processes are altered in CF disease to account for organ-specific secretory phenotypes.
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Affiliation(s)
- Raymond A Frizzell
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
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Larsen EH. Reconciling the Krogh and Ussing interpretations of epithelial chloride transport - presenting a novel hypothesis for the physiological significance of the passive cellular chloride uptake. Acta Physiol (Oxf) 2011; 202:435-64. [PMID: 21288306 DOI: 10.1111/j.1748-1716.2010.02239.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In 1937, August Krogh discovered a powerful active Cl(-) uptake mechanism in frog skin. After WWII, Hans Ussing continued the studies on the isolated skin and discovered the passive nature of the chloride uptake. The review concludes that the two modes of transport are associated with a minority cell type denoted as the γ-type mitochondria-rich (MR) cell, which is highly specialized for epithelial Cl(-) uptake whether the frog is in the pond of low [NaCl] or the skin is isolated and studied by Ussing chamber technique. One type of apical Cl(-) channels of the γ-MR cell is activated by binding of Cl(-) to an external binding site and by membrane depolarization. This results in a tight coupling of the uptake of Na(+) by principal cells and Cl(-) by MR cells. Another type of Cl(-) channels (probably CFTR) is involved in isotonic fluid uptake. It is suggested that the Cl(-) channels serve passive uptake of Cl(-) from the thin epidermal film of fluid produced by mucosal glands. The hypothesis is evaluated by discussing the turnover of water and ions of the epidermal surface fluid under terrestrial conditions. The apical Cl(-) channels close when the electrodiffusion force is outwardly directed as it is when the animal is in the pond. With the passive fluxes eliminated, the Cl(-) flux is governed by active transport and evidence is discussed that this is brought about by an exchange of cellular HCO(3) (-) with Cl(-) of the outside bath driven by an apical H(+) V-ATPase.
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Affiliation(s)
- Erik Hviid Larsen
- Department of Biology, University of Copenhagen, Copenhagen Ø, Denmark.
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Hamilton KL. Ussing's "Little Chamber": 60 Years+ Old and Counting. Front Physiol 2011; 2:6. [PMID: 21603225 PMCID: PMC3093741 DOI: 10.3389/fphys.2011.00006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 02/14/2011] [Indexed: 12/26/2022] Open
Affiliation(s)
- Kirk L Hamilton
- Department of Physiology, Otago School of Medical Sciences, University of Otago Dunedin, New Zealand
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Quinton PM. Role of epithelial HCO3⁻ transport in mucin secretion: lessons from cystic fibrosis. Am J Physiol Cell Physiol 2010; 299:C1222-33. [PMID: 20926781 DOI: 10.1152/ajpcell.00362.2010] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The invitation to present the 2010 Hans Ussing lecture for the Epithelial Transport Group of the American Physiological Society offered me a unique, special, and very surprising opportunity to join in saluting a man whom I met only once, but whose work was the basis, not only for my career, but also for finding the molecular defect in the inherited disease cystic fibrosis (CF). In this context, I will venture to make the tribute with a new explanation of why a mutation in a single gene that codes for an anion channel can cause devastation of multiple epithelial systems with pathogenic mucus. In so doing, I hope to raise awareness of a new role for that peculiar anion around which so much physiology revolves, HCO(3)(-). I begin by introducing CF pathology as I question the name of the disease as well as the prevalent view of the basis of its pathology by considering: 1) mucus, 2) salt, and 3) HCO(3)(-). I then present recent data showing that HCO(3)(-) is required for normal mucus discharge, and I will close with conjecture as to how HCO(3)(-) may support mucus discharge and why the failure to transport this electrolyte is pathogenic in CF.
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Affiliation(s)
- Paul M Quinton
- Department of Pediatrics, Rady Children’s Hospital, University of California San Diego School of Medicine, La Jolla, California 92093-0830, USA.
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Palmer LG, Andersen OS. The two-membrane model of epithelial transport: Koefoed-Johnsen and Ussing (1958). ACTA ACUST UNITED AC 2009; 132:607-12. [PMID: 19029371 PMCID: PMC2585867 DOI: 10.1085/jgp.200810149] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Lawrence G Palmer
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10065, USA.
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Brown DR, O’Grady SM. The Ussing Chamber and Measurement of Drug Actions on Mucosal Ion Transport. ACTA ACUST UNITED AC 2008; Chapter 7:Unit 7.12. [DOI: 10.1002/0471141755.ph0712s41] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- David R. Brown
- University of Minnesota, Departments of Veterinary & Biomedical Sciences (DRB) and Animal Science (SMO) St. Paul Minnesota
| | - Scott M. O’Grady
- University of Minnesota, Departments of Veterinary & Biomedical Sciences (DRB) and Animal Science (SMO) St. Paul Minnesota
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Lyte M. The biogenic amine tyramine modulates the adherence of Escherichia coli O157:H7 to intestinal mucosa. J Food Prot 2004; 67:878-83. [PMID: 15151221 DOI: 10.4315/0362-028x-67.5.878] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The environmental factors that influence the ability of Escherichia coli O157:H7 to attach to the intestinal mucosa are incompletely understood. In the present study, the ability of one of the most common biogenic amines present in food, tyramine, to influence the ability of E. coli O157:H7 to adhere to murine cecal mucosa was examined. Ex vivo full-thickness sheets of murine cecum were mounted in Ussing chambers, which preserved the enteric nervous system innervation of the luminal epithelia and thereby allowed us to achieve a closer approximation of bacterial adherence than would be encountered in vivo. After exposure of the luminal aspect of the cecum to tyramine, E. coli O157:H7 was added for 90 min. The cecal tissue was then removed and washed, and adhered E. coli O157:H7 was enumerated using a selective medium. Tyramine significantly increased E. coli O157:H7 adherence to cecal mucosa when compared to that of controls. The 50% effective concentration of tyramine was 92.6 microM. Specific adrenergic antagonists were then employed to examine whether the effect of tyramine was mediated through alpha- or beta-adrenergic receptors on the intestinal tissue. Pretreatment of tissues with either the alpha-adrenergic receptor antagonist phentolamine or the beta-adrenergic receptor antagonist propranolol prevented the action of tyramine. Measurement of active transepithelial ion transport and ionic permeability in the cecal sheets before and after the addition of tyramine and E. coli O157:H7 did not show any impairment of tissue viability or transepithelial conductance. Further, tyramine did not influence either the growth of E. coli O157:H7 or the expression of the intimin attachment factor. The present findings suggest that biogenic amines, such as tyramine, present within the food matrix influence host susceptibility to E. coli O157:H7 infection.
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Affiliation(s)
- Mark Lyte
- Department of Surgery, Minneapolis Medical Research Foundation/Hennepin County Medical Center, 914 South Eighth Street, Minneapolis, Minnesota 55404, USA.
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