Interaction of Tetraethylammonium Ion Derivatives with the Potassium Channels of Giant Axons
Open Access
- 1 October 1971
- journal article
- Published by Rockefeller University Press in The Journal of general physiology
- Vol. 58 (4) , 413-437
- https://doi.org/10.1085/jgp.58.4.413
Abstract
A number of compounds related to TEA+ (tetraethylammoniumion) were injected into squid axons and their effects on gK (the potassium conductance) were determined. In most of these ions a quaternary nitrogen is surrounded by three ethyl groups and a fourth group that is very hydrophobic. Several of the ions cause inactivation of gK, a type of ionic gating that is not normally seen in squid axon; i.e., after depolarization gK increases and then spontaneously decreases to a small fraction of its peak value even though the depolarization is maintained. Observations on the mechanism of this gating show that (a) QA (quaternary ammonium) ions only enter K+ channels that have open activation gates (the normal permeability gates). (b) The activation gates of QA-occluded channels do not close readily. (c) Hyperpolarization helps to clear QA ions from the channels. (d) Raising the external K+ concentration also helps to clear QA ions from the channels. Observations (c) and (d) strongly suggest that K+ ions traverse the membrane by way of pores, and they cannot be explained by the usual type of carrier model. The data suggest that a K+ pore has two distinct parts: a wide inner mouth that can accept a hydrated K+ ion or a TEA+-like ion, and a narrower portion that can accept a dehydrated or partially dehydrated K+ ion, but not TEA+.Keywords
This publication has 20 references indexed in Scilit:
- Turnover Numbers of Membrane Carriers and the Action of the Polypeptide AntibioticsNature, 1968
- Charges and Potentials at the Nerve SurfaceThe Journal of general physiology, 1968
- Structure of the K+ complex with nonactin, a macrotetrolide antibiotic possessing highly specific K+ transport propertiesJournal of Molecular Biology, 1967
- Tetrodotoxin's highly selective blockage of an ionic channel.1967
- Antibiotic-mediated transport of alkali ions across lipid barriers.Proceedings of the National Academy of Sciences, 1967
- Development of K+Na+ discrimination in experimental bimolecular lipid membranes by macrocyclic antibioticsBiochemical and Biophysical Research Communications, 1967
- Time Course of TEA+-Induced Anomalous Rectification in Squid Giant AxonsThe Journal of general physiology, 1966
- Anomalous Rectification in the Squid Giant Axon Injected with Tetraethylammonium ChlorideThe Journal of general physiology, 1965
- A quantitative description of membrane current and its application to conduction and excitation in nerveThe Journal of Physiology, 1952
- The dual effect of membrane potential on sodium conductance in the giant axon of LoligoThe Journal of Physiology, 1952