Abstract
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 language | English (US) |
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Pages (from-to) | 61-78 |
Number of pages | 18 |
Journal | Journal of General Physiology |
Volume | 75 |
Issue number | 1 |
DOIs | |
State | Published - Jan 1 1980 |
Externally published | Yes |
ASJC Scopus subject areas
- Physiology