Effect of sodium on amiloride- and triamterene-induced current fluctuations in isolated frog skin

The apparent association constants of two agents, amiloride and triamterene, that block the Na-selective channel of apical membrane of frog skin are shown to decrease as the Na concentration is increased in the apical bathing solution in isolated skin of the frog, Rana temporaria, Rana esculenta, and Rana pipiens. These results were obtained in "normally polarized" skins. These effects were independent of the anion used (chloride or methylsulfate) or the cation used as the Na substitute (Tris, DDA, or K ion). When NaCl was replaced with mannitol, the Na effect on the amiloride association rate constant persisted, which shows that ionic strength was not critically involved. The amiloride corner frequency was unaffected when the clamp potential was altered from +100 to -60 mV. The Na dependence was greatly attenuated or absent when the serosal surface was bathed in 120 mM K Ringer's, an effect that appears to be attributable to some pharmacological effect of high serosal K. A previously described three- state model is used to analyze the inhibitory effect of Na on the blocker association rate constant.

• Publication year

  1986

• Venue

  The Journal of General Physiology

• Publication date

  1986-03-01

• Fields of study

  Biology, Medicine, Chemistry

• Identifiers
  DOI 10.1085/JGP.87.3.425PMID 2420917PMCID 2217608
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar, PubMed

• No claims are published for this paper.

• No concepts are published for this paper.

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