Dependence of chloride permeability on sodium in the isolated frog skin1

Journal/Book: Reprinted from THE AMERICAN JOURNAL OF PHYOIOLOGY Vol. 204 No. 6 June 1963. 1963;

Abstract: Department of Physiology University of California Berkeley California Received for publication 26 October 1962. 1 This study was supported by Grant H-6063 from the National Institutes of Health. MACEY ROBERT L AND STUART MEYERS. Dependence of chloride permeability an sodium in the isolated frog skin.-By substituting impermeable SO4 ions for 90 % Jo of Cl the response of the potential difference across an isolated frog skin to a tenfold reduction in Cl concentration bathing the external (epithelial) surface was measured while maintaining a constant composition of all other ions. In the presence of Na the external surface does not behave like a Cl electrode presumably because of the presence of permeable Na ions. However in the absence of Na (replaced by the relatively impermeable K or Mg ions) the potential response to a tenfold dilution in Cl is much smaller than in its presence. Measurements of Cl36 flux indicate that the Cl conductance is depressed when Na is withdrawn. The results suggest a dependence of the Cl permeability of the external barrier an Na ions. ___MH

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