Survival of K+ permeability and gating currents in squid axons perfused with K+-free media

W. Almers, C. M. Armstrong

Research output: Contribution to journalArticlepeer-review

68 Scopus citations


K+ currents were recorded in squid axons internally perfused with impermeant electrolyte. Total absence of permeant ions inside and out leads to an irreversible loss of potassium conductance with a time constant of -11 min at 8°C. Potassium channels can be protected against this effect by external K+, Cs+, NH4+, and Rb+ at concentrations of 100-440 mM. These experiments suggest that a K+ channel is normally occupied by one or more small cations, and becomes nonfunctional when these cations are removed. A large charge movement said to be related to K+ channel gating in frog skeletal muscle is absent in squid giant axons. However, deliberate destruction of K+ conductance by removal of permeant cations is accompanied by measurable loss in asymmetric charge movement. This missing charge component is large enough to contain a contribution from K+ gating charge movements of more than five elementary charges per channel.

Original languageEnglish (US)
Pages (from-to)61-78
Number of pages18
JournalJournal of General Physiology
Issue number1
StatePublished - Jan 1 1980
Externally publishedYes

ASJC Scopus subject areas

  • Physiology


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