Repulsion between tetraethylammonium ions in cloned voltage-gated potassium channels

C. F. Newland, J. P. Adelman, B. L. Tempel, W. Almers

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Abstract

Teraethylammonium ion (TEA+)blocks voltage-gated K+ channels by acting at two sites located at opposite ends of the aqueous pore. This allowed us to test two predictions made by models of ion permeation, namely that K+ channels can be simultaneously occupied by multiple ions and that the ions repel each other. We show that externally applied TEA+ antagonize block by internal TEA+ and vice versa. The antagonism is less than predicted for competitive binding, hence TEA+ may occupy both sites simultaneously. External TEA+ and internal TEA+ reduce each others affinity 4-to 5-fold. In addition, K+ antagonizes block by TEA+ at the opposite side of the membrane, and external TEA+ antagonizes is block by internal Ba2+. The antagonism between ions applied at opposite sides of the membrane may be common to all cations binding to K+ channels.

Original languageEnglish (US)
Pages (from-to)975-982
Number of pages8
JournalNeuron
Volume8
Issue number5
DOIs
StatePublished - May 1992

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ASJC Scopus subject areas

  • Neuroscience(all)

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