Summary
Gallbladders transport isotonically over a wide range of osmolarities. This ability has been assumed to depend on the geometry of the lateral intercellular spaces. We report that this geometry in theNecturus gallbladder varies extensively with the external osmolarity and dependsin vitro on the integrity of the subepithelial tissues. The structure of the living epithelium was studied by Nomarski light microscopy while ultrastructural effects were revealed by electron microscopy. The short-term effects (<60 min) of low external osmolarities were: 1) the cells became bell-shaped with an increased cell height measured centrally, 2) lateral intercellular spaces lost their convoluted character; and 3) numerous membrane-bound cavities appeared in the cells. Furthermore, long-term exposure to the low external osmolarities caused an uneven density of epithelial cells. With subepithelial tissues intact, blistering of the epithelium cell layer was evident. Qualitative electron-microscopic data indicate that the membrane of the cavities was recruited from the basolateral cell membrane. This agrees well with light-microscopic observation that the cavities were initiated as invaginations of this cell membrane.
Similar content being viewed by others
References
Allen, R.D., David, G.B., Nomarski, G. 1969. The Zeiss-Nomarski differential interference equipment for transmitted-light microscopy.Z. Wiss. Mikrosk. 69:193–221
Beadle, L.C. 1934. Osmotic regulation inGunda ulvae.J. Exp. Biol. 11:382–396
Blom, H., Helander, H.F. 1977. Quantitative electron microscopical studies onin vitro incubated rabbit gallbladder epithelium.J. Membrane Biol. 37:45–61
Bundgaard, M., Zeuthen, T. 1981. The structure ofNecturus gall bladder epithelium at low osmolarities.J. Physiol. (London) 316:60P
Case, R.M., Harper, A.A., Scratcherd, T. 1968. Water and electrolyte secretion by the perfused pancreas of the cat.J. Physiol. (London) 196:133–149
Diamond, J.M. 1964. The mechanism of isotonic water transport.J. Gen. Physiol. 48:15–42
Diamond, J.M. 1979. Osmotic water flow in leaky epithelia.J. Membrane Biol. 51:195–216
Diamond, J.M., Bossert, W.H. 1967. Standing gradient osmotic flow: A mechanism for coupling of salt and water transport in epithelia.J. Gen. Physiol. 50:2061–2083
Hill, A.E. 1975. Solute-solvent coupling in epithelia: A critical examination of the standing-gradient osmotic flow theory.Proc. R. Soc. London 190:99–114
Hill, A.E. 1980. Salt-water coupling in leaky epithelia.J. Membrane Biol. 56:177–182
Hill, B.S., Hill, A.E. 1978. Fluid transfer byNecturus gall bladder epithelium as a function of osmolarity.Proc. R. Soc. London 200:151–162
Maddrell, S.H.P. 1969. Secretion by the malphigian tubules ofRhodnius. The movements of ions and water.J. Exp. Biol. 51:71–97
Maunsbach, A.B., Boulpaep, E.L. 1980. Hydrostatic pressure changes related to paracellular shunt ultrastructure in proximal tubule.Kidney Int. 17:100–116
Ramsey, J.A., Brown, R.H.J. 1955. Simplified apparatus and procedure for freezing-point determination upon small volumes of fluid.J. Sci. Instrum. 32:372–375
Schifferdecker, E., Frömter, E. 1978. The A C impedance of Necturus gall bladder epithelium.Pfluegers Arch. 377:125–133
Spring, K.R., Hope, A. 1978. Size and shape of the lateral intercellular spaces in a living epithelium.Science 200:54–58
Weibel, E.R., Bolender, R.P. 1973. Stereological techniques for electron microscopic morphometry.In: Principles and Techniques of Electron Microscopy. M.A. Hayat, editor. Vol. 3, p. 237. Van Nostrand-Reinhold, New York
Zeuthen, T. 1976. The vertebrate gall bladder. The routes of ion transport.In: Fluid Transport in Epithelia. B.L. Gupta, R.B. Moreton, J.L. Oschman and B.J. Wall, editors. pp. 511–537. Academic Press, New York
Zeuthen, T. 1981a. The intracellular osmolarity during isotonic fluid transport in gall bladder.In: Alfred Benzon Symp. 15. H.H. Ussing, N. Bindslev, N.A. Lassen and O. Steen-Knudsen, editors. pp. 313–331. Munksgaard, Copenhagen
Zeuthen, T. 1981b. Relations between intracellular ion activities and extracellular osmolarity inNecturus gallbladder epithelium.J. Membrane Biol. 66:109–121
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bundgaard, M., Zeuthen, T. Structure ofNecturus gallbladder epithelium during transport at low external osmolarities. J. Membrain Biol. 68, 97–105 (1982). https://doi.org/10.1007/BF01872258
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01872258