Control of Na+ and H+ transports by exocytosis/endocytosis phenomena in a tight epithelium

1993 ◽  
Vol 134 (3) ◽  
Author(s):  
Isabelle Lacoste ◽  
Emmanuelle Brochiero ◽  
Jordi Ehrenfeld
Keyword(s):  
Tight Epithelium

Cultured branchial epithelia from freshwater fish gills

1997 ◽  
Vol 200 (6) ◽  
pp. 1047-1059 ◽  
Author(s):  
C M Wood ◽  
P Pärt
Keyword(s):  
Primary Cultures ◽  
Transepithelial Resistance ◽  
Apical Surface ◽  
Pavement Cells ◽  
Cell Layers ◽  
Cultured Epithelium ◽  
Net Fluxes ◽  
Foetal Bovine Serum ◽  
Tight Epithelium

We have developed a method for the primary culture of gill epithelial cells from freshwater rainbow trout on permeable supports, polyethylene terephthalate membranes ('filter inserts'). Primary cultures of gill cells (6-9 days in Leibowitz L-15 culture medium plus foetal bovine serum and glutamine) are trypsinized and the cells seeded onto the inserts. After 6 days of growth with L-15 medium on both surfaces (approximately isotonic to trout plasma), the cells form a tight epithelium as judged from a progressive rise in transepithelial resistance which reaches a stable plateau for a further 6 days, as long as L-15 exposure is continued on both surfaces. The cultured epithelium (approximately 8 µm thick) typically consists of 2-4 overlapping cell layers organized as in the lamellae in vivo, with large intercellular spaces, multiple desmosomes and putative tight junctions. The cells appear to be exclusively pavement-type cells with an apical surface glycocalyx, an abundance of rough endoplasmic reticulum, no selective DASPEI staining and relatively few mitochondria. Transepithelial resistance (approximately 3.5 k cm2), permeability to a paracellular marker (polyethylene glycol-4000; 0.17x10(-6) cm s-1) and unidirectional flux of Na+ and Cl- (approximately 300 nmol cm-2 h-1) all appear realistic because they compare well with in vivo values; net fluxes of Na+ and Cl- are zero. The preparation acidifies the apical medium, which accumulates a greater concentration of ammonia. Upon exposure to apical freshwater, resistance increases six- to elevenfold and a basolateral-negative transepithelial potential (TEP) develops as in vivo. These responses occur even when mannitol is used to prevent changes in apical osmotic pressure. Net Na+ and Cl- loss rates are low over the first 12 h (-125 nmol cm-2 h-1) but increase substantially by 48 h. The elevated resistance and negative TEP gradually attenuate but remain significantly higher than pre-exposure values after 48 h of apical freshwater exposure. The preparation may provide a valuable new tool for characterizing some of the mechanisms of active and passive ion transport in the pavement cells of the freshwater gill.

Current-voltage relationship of the basolateral membrane of a tight epithelium

1979 ◽  
Vol 555 (3) ◽  
pp. 519-523 ◽  
Author(s):  
Nancy K. Wills ◽  
Douglas C. Eaton ◽  
Simon A. Lewis ◽  
Mark S. Ifshin
Keyword(s):  
Basolateral Membrane ◽  
Current Voltage ◽  
Relationship Of ◽  
Current Voltage Relationship ◽  
Voltage Relationship ◽  
Tight Epithelium

scholarly journals Single anion-selective channels in basolateral membrane of a mammalian tight epithelium.

1985 ◽  
Vol 82 (22) ◽  
pp. 7791-7795 ◽  
Author(s):  
J. W. Hanrahan ◽  
W. P. Alles ◽  
S. A. Lewis
Keyword(s):  
Basolateral Membrane ◽  
Tight Epithelium

scholarly journals Nystatin as a probe for investigating the electrical properties of a tight epithelium.

1977 ◽  
Vol 70 (4) ◽  
pp. 427-440 ◽  
Author(s):  
S A Lewis ◽  
D C Eaton ◽  
C Clausen ◽  
J M Diamond
Keyword(s):  
Apical Membrane ◽  
Basolateral Membrane ◽  
Membrane Conductance ◽  
Voltage Divider ◽  
Junctional Conductance ◽  
Transepithelial Voltage ◽  
Almost All ◽  
Voltage Divider Ratio ◽  
Rabbit Urinary Bladder ◽  
Tight Epithelium

We show how the antibiotic nystatin may be used in conjunction with microelectrodes to resolve transepithelial conductance Gt into its components: Ga, apical membrane conductance; Gbl, basolateral membrane conductance; and Gj, junctional conductance. Mucosal addition of nystatin to rabbit urinary bladder in Na+-containing solutions caused Gt to increase severalfold to ca. 460 micrometerho/muF, and caused the transepithelial voltage Vt to approach +50 mV regardless of its initial value. From measurements of Gt and the voltage-divider ratio as a function of time after addition or removal of nystatin, values for Ga, Gbl, and Gj of untreated bladder could be obtained. Nystatin proved to have no direct effect on Gbl or Gj but to increase Ga by about two orders of magnitude, so that the basolateral membrane then provided almost all of the electrical resistance in the transcellular pathway. The nystatin channel in the apical membrane was more permeable to cations than to anions. The dose-response curve for nystatin had a slope of 4.6. Use of nystatin permitted assessment of whether microelectrode impalement introduced a significant shunt conductance into the untreated apical membrane, with the conclusion that such a shunt was negligible in the present experiments. Nystatin caused a hyperpolarization of the basolateral membrane potential in Na+-containing solutions. This may indicate that the Na+ pump in this membrane is electrogenic.

Na+ transport by rabbit urinary bladder, a tight epithelium

1976 ◽  
Vol 28 (1) ◽  
pp. 1-40 ◽  
Author(s):  
Simon A. Lewis ◽  
Jared M. Diamond
Keyword(s):  
Urinary Bladder ◽  
Na Transport ◽  
Rabbit Urinary Bladder ◽  
Tight Epithelium

scholarly journals Volume-activated chloride permeability can mediate cell volume regulation in a mathematical model of a tight epithelium.

1990 ◽  
Vol 96 (2) ◽  
pp. 319-344 ◽  
Author(s):  
J Strieter ◽  
J L Stephenson ◽  
L G Palmer ◽  
A M Weinstein
Keyword(s):  
Mathematical Model ◽  
Cell Volume ◽  
Volume Regulation ◽  
Electrical Potential ◽  
Cell Volume Regulation ◽  
York Academy ◽  
Constant Field ◽  
Chloride Permeability ◽  
Volume Regulatory Decrease ◽  
Tight Epithelium

Cell volume regulation during anisotonic challenge is investigated in a mathematical model of a tight epithelium. The epithelium is represented as compliant cellular and paracellular compartments bounded by mucosal and serosal bathing media. Model variables include the concentrations of Na, K, and Cl, hydrostatic pressure, and electrical potential, and the mass conservation equations have been formulated for both steady-state and time-dependent problems. Ionic conductance is represented by the Goldman constant field equation (Civan, M.M., and R.J. Bookman. 1982. Journal of Membrane Biology. 65:63-80). A basolateral cotransporter of Na, K, and Cl with 1:1:2 stoichiometry (Geck, P., and E. Heinz. 1980. Annals of the New York Academy of Sciences. 341:57-62.) and volume-activated basolateral ion permeabilities are incorporated in the model. MacRobbie and Ussing (1961. Acta Physiologica Scandinavica. 53:348-365.) reported that the cells of frog skin exhibit osmotic swelling followed by a volume regulatory decrease (VRD) when the serosal bath is diluted to half the initial osmolality. Similar regulation is achieved in the model epithelium when both a basolateral cotransporter and a volume-activated Cl permeation path are included. The observed transepithelial potential changes could only be simulated by allowing volume activation of the basolateral K permeation path. The fractional VRD, or shrinkage as percent of initial swelling, is examined as a function of the hypotonic challenge. The fractional VRD increases with increasing osmotic challenge, but eventually declines under the most severe circumstances. This analysis demonstrates that the VRD response depends on the presence of adequate intracellular chloride stores and the volume sensitivity of the chloride channel.

scholarly journals Rheogenic sodium transport in a tight epithelium, the amphibian skin.

1980 ◽  
Vol 302 (1) ◽  
pp. 281-295 ◽  
Author(s):  
W Nagel
Keyword(s):  
Sodium Transport ◽  
Amphibian Skin ◽  
Tight Epithelium

scholarly journals Impedance analysis of a tight epithelium using a distributed resistance model

1979 ◽  
Vol 26 (2) ◽  
pp. 291-317 ◽  
Author(s):  
C. Clausen ◽  
S.A. Lewis ◽  
J.M. Diamond
Keyword(s):  
Impedance Analysis ◽  
Resistance Model ◽  
Tight Epithelium
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