Autoradiographic localization of tritiated ouabain-sensitive sodium pump sites in ion transporting epitheliaSA Ernst and JW Mills
The freeze-dry autoradiographic method devised originally by Stirling (J Cell Biol 53:704, 1972) to localize Na+ pump sites with (3H)ouabain is reviewed. Biochemical, physiological, and autoradiographic data are discussed which establish that ouabain binding to intact tissue conforms to rigid criteria for high Na+ pump specificity. Among these are that glycoside binding exhibits saturation kinetics, ligand dependence, and close correlation with degrees of inhibition of Na+-K+- ATPase and Na+ transport. Moreover, localization of Na+ pump sites by this technique shows a cell and membrane specificity which mirrors that obtained by cytochemical and immunocytochemical methods. In addition to resolving cell-specific patterns of localization in heterogeneous tissues, the demonstration of Na+-K+-ATPase by these techniques indicates that Na+ pumps are distributed uniformly along plasmalemmal surfaces and are restricted to the basolateral interface in reabsorptive and secretory epithelia despite the opposing polarity of net transepithelial electrolyte transport.
Volume 28,
Issue 1,
pp. 72-77,
01/01/1980
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L. Shoshani, R. G. Contreras, M. L. Roldan, J. Moreno, A. Lazaro, M. S. Balda, K. Matter, and M. Cereijido The Polarized Expression of Na+,K+-ATPase in Epithelia Depends on the Association between {beta}-Subunits Located in Neighboring Cells Mol. Biol. Cell, March 1, 2005; 16(3): 1071 - 1081. [Abstract] [Full Text] [PDF] |
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M. Cereijido, R. G. Contreras, and L. Shoshani Cell Adhesion, Polarity, and Epithelia in the Dawn of Metazoans Physiol Rev, October 1, 2004; 84(4): 1229 - 1262. [Abstract] [Full Text] [PDF] |
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W. Marshall, T. Emberley, T. Singer, S. Bryson, and S. Mccormick Time course of salinity adaptation in a strongly euryhaline estuarine teleost, fundulus heteroclitus: a multivariable approach J. Exp. Biol., January 6, 1999; 202(11): 1535 - 1544. [Abstract] [PDF] |
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