Effects of a low-Ca2+ environment on branchial chloride cell morphology in chum salmon fry and immunolocalization of Ca2+-ATPase in chloride cells

2002 ◽  
Vol 80 (6) ◽  
pp. 1100-1108 ◽  
Author(s):  
Katsuhisa Uchida ◽  
Sanae Hasegawa ◽  
Toyoji Kaneko
Keyword(s):  
Electron Microscope ◽  
Cell Morphology ◽  
Cellular Localization ◽  
Chum Salmon ◽  
Basolateral Membrane ◽  
Chloride Cell ◽  
Immunocytochemical Staining ◽  
Chloride Cells ◽  
Oncorhynchus Keta ◽  
Morphological Evidence

To clarify the involvement of branchial chloride cells in Ca2+ uptake in fresh water (FW), chloride-cell morphology was compared in chum salmon (Oncorhynchus keta) fry acclimated to defined FWs with different Ca2+ concentrations (0, 0.1, and 0.5 mM). Using immunocytochemical staining with an antiserum specific for Na+,K+-ATPase, chloride cells were detected in both filament and lamellar epithelia. The numbers and sizes of chloride cells in the lamellar epithelia were greater in the low-Ca2+ groups (0 and 0.1 mM Ca2+) than in the normal-Ca2+ groups (0.5 mM Ca2+ and normal FW), whereas filament chloride cells were not affected in number or size by the environmental Ca2+ concentration. Electron-microscope observations also revealed that enlarged lamellar chloride cells were more frequently observed in the 0 mM Ca2+ group than in the 0.5 mM Ca2+ group. To obtain morphological evidence for Ca2+ uptake through the branchial epithelia, cellular localization of Ca2+-ATPase was examined with a monoclonal antibody specific for human erythrocyte Ca2+-ATPase. Ca2+-ATPase immunoreactivity was detected in Na+,K+-ATPase-immunoreactive chloride cells in both filament and lamellar epithelia. Using electron-microscope immunocytochemistry, Ca2+-ATPase was found to be localized in the tubular system, which is continuous with the basolateral membrane of chloride cells. These findings indicate that chloride cells in the lamellar epithelia activated by a low Ca2+ concentration may constitute the extra Ca2+ and NaCl uptake capacity required to maintain homeostasis in soft water.

Role of Na-K-ATPase in chloride cell function

1980 ◽  
Vol 238 (3) ◽  
pp. R246-R250 ◽  
Author(s):  
F. H. Epstein ◽  
P. Silva ◽  
G. Kormanik
Keyword(s):  
Cell Function ◽  
Chloride Transport ◽  
Basolateral Membrane ◽  
Chloride Cell ◽  
Chloride Cells ◽  
Ion Movement ◽  
Gill Filaments ◽  
Ion Movements ◽  
Ion Species

In seawater eels the efflux of sodium (and chloride) across the gill is directly proportional to the activity of Na-K-ATPase in homogenates of gill filaments. The rate of ion movement, however, is substantially greater than at the temperature of seawater. Na-K-ATPase is localized predominantly on the basolateral surface of the chloride cell so that ouabain inhibits from the blood side rather than from the apical or mucosal surface of chloride cells. Chloride, rather than sodium, is probably the actively transported ion species, and an attractive hypothesis for active chloride transport is one that invokes the cotransport of chloride with sodium across the basolateral membrane, the energy for which is supplied indirectly by the operation of the Na-K-ATPase pump. Exposure to freshwater sharply dissociates ion movements from Na-K-ATPase activity, possibly by changing the permeability of cell membranes to chloride movements.

In vivo sequential changes in chloride cell morphology in the yolk-sac membrane of mozambique tilapia (Oreochromis mossambicus) embryos and larvae during seawater adaptation

1999 ◽  
Vol 202 (24) ◽  
pp. 3485-3495 ◽  
Author(s):  
J. Hiroi ◽  
T. Kaneko ◽  
M. Tanaka
Keyword(s):  
Fresh Water ◽  
Cell Morphology ◽  
Sea Water ◽  
Oreochromis Mossambicus ◽  
Yolk Sac ◽  
Chloride Cell ◽  
Chloride Cells ◽  
Seawater Adaptation ◽  
Accessory Cells

Changes in chloride cell morphology were examined in the yolk-sac membrane of Mozambique tilapia (Oreochromis mossambicus) embryos and larvae transferred from fresh water to sea water. By labelling chloride cells with DASPEI, a fluorescent probe specific for mitochondria, we observed in vivo sequential changes in individual chloride cells by confocal laser scanning microscopy. In embryos transferred from fresh water to sea water 3 days after fertilization, 75 % of chloride cells survived for 96 h, and cells showed a remarkable increase in size. In contrast, the cell size did not change in embryos and larvae kept in fresh water. The same rate of chloride cell turnover was observed in both fresh water and sea water. Using differential interference contrast (DIC) optics and whole-mount immunocytochemistry with anti-Na(+)/K(+)-ATPase, we classified chloride cells into three developmental stages: a single chloride cell without an apical pit, a single chloride cell with an apical pit, and a multicellular complex of chloride and accessory cells with an apical pit. DIC and immunofluorescence microscopy revealed that single chloride cells enlarged and were frequently indented by newly differentiated accessory cells to form multicellular complexes during seawater adaptation. These results indicate that freshwater-type single chloride cells are transformed into seawater-type multicellular complexes during seawater adaptation, suggesting plasticity in the ion-transporting functions of chloride cells in the yolk-sac membrane of tilapia embryos and larvae.

The interrelationships between gill chloride cell morphology and ionic uptake in four freshwater teleosts

1992 ◽  
Vol 70 (9) ◽  
pp. 1775-1786 ◽  
Author(s):  
S. F. Perry ◽  
G. G. Goss ◽  
P. Laurent
Keyword(s):  
Cell Morphology ◽  
Chloride Cell ◽  
Whole Body ◽  
Chloride Cells ◽  
Scanning Electron Micrographs ◽  
Interspecific Variability ◽  
Fractional Area ◽  
Ionic Uptake ◽  
Scanning Electron ◽  
Freshwater Teleosts

We have investigated the role of the gill chloride cell in transbranchial Na+ and Cl− uptake in four species of freshwater teleost maintained in water of identical ionic composition. The basic experimental protocol was to determine whether interspecific variability in the rates of whole body Na+ or Cl− uptake could be accounted for by similar interspecific variability in the fractional area of branchial chloride cells exposed to the external environment. To investigate the underlying cause(s) of intraspecific variability, chronic (10 day) treatment with cortisol in each species was used as a tool to evoke variations in both the rates of ionic uptake and chloride cell morphology. Examination of transmission and scanning electron micrographs revealed distinctive chloride cell and pavement cell morphology in each species. The results of quantitative morphometry, based on analysis of scanning electron micrographs, demonstrated that European eel (Anguilla anguilla) possessed the lowest chloride cell fractional area on the filament epithelium (11 288 ± 2133 μm2/mm2) followed, in increasing order, by brown bullhead catfish (Ictalurus nebulosus; 48 341 ± 7694 μm2/mm2), tilapia (Oreochromis mossambicus; 85 194 ± 10 326 μm2/mm2), and rainbow trout (Oncorhynchus mykiss; 146 333 ± 31 356 μm2/mm2). With the exception of rainbow trout, chronic treatment with cortisol caused significant increases in the chloride cell fractional area of filament epithelium owing to enlargement of the surface area of individual chloride cells and (or) proliferation of chloride cells. Both the inter- and intra-specific differences in chloride cell fractional area were reflected by similar differences in whole body Cl− and Na+ uptake. The results of correlation analysis revealed (with the exception of whole body Na+ uptake in A. anguilla) significant correlations between chloride cell fractional area and the rates of ionic uptake within and among the four species that were examined. These data suggest that the chloride cell is a significant site of ionic uptake in freshwater teleosts and that both inter- and intra-specific differences in the rates of ionic uptake can be explained by variability in the surface area of chloride cells on the gill epithelia.

scholarly journals The surface epithelium of teleostean fish gills. Cellular and junctional adaptations of the chloride cell in relation to salt adaptation.

1979 ◽  
Vol 80 (1) ◽  
pp. 96-117 ◽  
Author(s):  
C Sardet ◽  
M Pisam ◽  
J Maetz
Keyword(s):  
Salt Water ◽  
Freeze Fracture ◽  
Morphological Characteristics ◽  
Chloride Cell ◽  
Chloride Cells ◽  
Surface Epithelium ◽  
Salt Adaptation ◽  
Resistance Pathway ◽  
Shallow Junctions ◽  
Respiratory Cells

Various species of teleostean fishes were adapted to fresh or salt water and their gill surface epithelium was examined using several techniques of electron microscopy. In both fresh and salt water the branchial epithelium is mostly covered by flat respiratory cells. They are characterized by unusual outer membrane fracture faces containing intramembranous particles and pits in various stages of ordered aggregation. Freeze fracture studies showed that the tight junctions between respiratory cells are made of several interconnecting strands, probably representing high resistance junctions. The organization of intramembranous elements and the morphological characteristics of the junctions do not vary in relation to the external salinity. Towards the base of the secondary gill lamellae, the layer of respiratory cells is interrupted by mitochondria-rich cells ("chloride cells"), also linked to respiratory cells by multistranded junctions. There is a fundamental reorganization of the chloride cells associated with salt water adaptation. In salt water young adjacent chloride cells send interdigitations into preexisting chloride cells. The apex of the seawater chloride cell is therefore part of a mosaic of sister cells linked to surrounding respiratory cells by multistranded junctions. The chloride cells are linked to each other by shallow junctions made of only one strand and permeable to lanthanum. It is therefore suggested that salt water adaptation triggers a cellular reorganization of the epithelium in such a way that leaky junctions (a low resistance pathway) appear at the apex of the chloride cells. Chloride cells are characterized by an extensive tubular reticulum which is an extension of the basolateral plasma membrane. It is made of repeating units and is the site of numerous ion pumps. The presence of shallow junctions in sea water-adapted fish makes it possible for the reticulum to contact the external milieu. In contrast in the freshwater-adapted fish the chloride cell's tubular reticulum is separated by deep apical junctions from the external environment. Based on these observations we discuss how solutes could transfer across the epithelium.

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