The Journal of Membrane Biology

, Volume 87, Issue 3, pp 249–252 | Cite as

Hydrosmotic salt effect in toad skin: Urea permeability and glutaraldehyde fixation of water channels

  • J. Aboulafia
  • F. Lacaz-Vieira
Articles

Summary

The “hydrosmotic salt effect” (HSE), the reversible dependence of skin osmotic water permeability upon the ionic concentration of the outer bathing solution, is known to induce the appearance of sucrose-impermeable pathways in the apical membrane of the outermost epithelial cell layer. Diffusional14C-urea permeability, measured in theJv=0 condition to prevent solvent drag effects, indicates that the newly formed pathways induced by HSE are narrower than the size of the urea molecule, being therefore highly selective for water molecules. After mild glutaraldehyde (2% solution) fixation of the apical membrane structures, the water channels induced by the HSE are no longer affected by the ionic strength of the outer solution. This indicates that the channel-forming membrane protein can be fixed in different configurations with the water channels in the open or closed states.

Key Words

toad skin hydrosmotic salt effect water permeability glutaraldehyde fixation urea permeability 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Aboulafia, J., Lacaz-Vieira, F. 1984. Vanadate and ouabain: A comparative study in toad skin.Pfluegers Arch. 401:204–208Google Scholar
  2. 2.
    Aboulafia, J., Sanioto, S.M.L., Lacaz-Vieira, F. 1983. Cellular Li+ opens paracellular path in toad skin: Amiloride blockable effect.J. Membrane Biol. 74:59–65Google Scholar
  3. 3.
    Andersen, B., Ussing, H.H. 1957. Solvent drag of non-electrolytes during osmotic flow through isolated toad skin and its response to antiduretic hormone.Acta Physiol. Scand. 39:228–239Google Scholar
  4. 4.
    Bartolini, A., Gliozzi, A., Richardson, I.W. 1973. Electrolytes control flows of water and sucrose through collagen membranes.J. Membrane Biol. 13:283–298Google Scholar
  5. 5.
    Benedictis, E.M., Lacaz-Vieira, F. 1982. Electrolytes control flows of water across the apical barrier in toad skin: The hydrosmotic salt effect.J. Membrane Biol. 67:125–135Google Scholar
  6. 6.
    Bourguet, J. 1966. Influence de la température sur la cinétique de l'augmentation de perméabilité à l'eau de la vessie de grenouille sous l'action de l'ocytocine.J. Physiol. (Paris) 58:476Google Scholar
  7. 7.
    Bourguet, J. 1968. Cinétique de la perméabilisation de la vessie de grenouille par l'ocytocine. Rôle du 3′,5′ adénosine monophosphate cyclique.Biochim. Biophys. Acta 150:104–112Google Scholar
  8. 8.
    Brown, D., Grosso, A., DeSousa, R.C. 1980. Isoproterenol induced intramembrane particle aggregation and water flux in toad epidermis.Biochim. Biophys. Acta 596:158–164Google Scholar
  9. 9.
    Chevalier, J., Bourguet, J., Hugon, J.S. 1974. Membrane-associated particles: Distribution in frog urinary bladder epithelium at rest and after oxytocin treatment.Cell Tissue Res. 152:129–140Google Scholar
  10. 10.
    Chevalier, J., Parisi, M., Bourguet, J., Gobin, R. 1983. The rate-limiting step in hydrosmotic response of frog urinary bladder.Cell Tissue Res. 228:345–355Google Scholar
  11. 11.
    DeSousa, R.C., Grosso, A. 1981. The mode of action of vasopressin: Membrane microstructure and biological transport.J. Physiol. (Paris) 77:643–669Google Scholar
  12. 12.
    Eggena, P. 1972. Glutaraldehyde-fixation method for determining the permeability to water of the toad urinary bladder.Endocrinology 91:240–246Google Scholar
  13. 13.
    Eggena, P. 1972. Osmotic regulation of toad bladder responsiveness to neurohypophyseal hormones.J. Gen. Physiol. 60:665–678Google Scholar
  14. 14.
    Eggena, P. 1972. Temperature dependence of vasopressin action on the toad bladder.J. Gen. Physiol. 59:519–533Google Scholar
  15. 15.
    Eggena, P. 1973. Inhibition of vasopressin-stimulated urea transport across the toad bladder by thiourea.J. Clin. Invest. 52:2963–2970Google Scholar
  16. 16.
    Erlij, D., Martínez-Palmomo, A. 1972. Opening of tight junctions in frog skin by hypertonic urea solutions.J. Membrane Biol. 9:229–240Google Scholar
  17. 17.
    Fischbarg, J., Whittembury, G. 1978. The effect of external pH on osmotic permeability, ion and fluid transport across isolated frog skin.J. Physiol. (London) 275:403–417Google Scholar
  18. 18.
    Kachadorian, W.A., Wade, J.B., DiScala, V.A. 1975. Vasopressin: Induced structural change in toad bladder luminal membrane.Science 190:67–69Google Scholar
  19. 19.
    Parker, J.C. 1984. Glutaraldehyde fixation of sodium transport in dog red blood cells.J. Gen. Physiol. 84:789–803Google Scholar
  20. 20.
    Sabatini, D.D., Bensch, K., Barrnett, R.J. 1963. Cytochemistry and electron microscopy. The preservation of cellular ultrastructure and enzymatic activity by aldehyde fixation.J. Cell Biol. 17:19–58Google Scholar
  21. 21.
    Schultz, S.G., Solomon, A.K. 1961. Determination of the effective hydrodynamic radii of small molecules by viscometry.J. Gen. Physiol. 44:1189–1199Google Scholar
  22. 22.
    Varanda, W.A., Lacaz-Vieira, F. 1978. Transients in toad skin: Short-circuit current and ionic fluxes related to inner sodium substitution by monovalent cations.J. Membrane Biol. 39:369–385Google Scholar

Copyright information

© Springer-Verlag 1985

Authors and Affiliations

  • J. Aboulafia
    • 1
  • F. Lacaz-Vieira
    • 1
  1. 1.Institute of Biomedical Sciences, Department of Physiology and BiophysicsUniversity of São PauloSão PauloBrazil

Personalised recommendations