Send to

Choose Destination
J Physiol. 1995 Jul 15;486 ( Pt 2):267-72.

Influence of permeating ions on potassium channel block by external tetraethylammonium.

Author information

Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta 30912, USA.


1. Block by external tetraethylammonium (TEA) was examined on currents carried by potassium (K+) and sodium (Na+) through the cloned delayed rectifier K+ channel Kv2.1. 2. In the presence of high intracellular K+ and high extracellular Na+, currents through the Kv2.1 channel were carried almost exclusively by K+. In the absence of both intracellular and extracellular K+, large currents were carried by Na+ through the Kv2.1 channel. 3. External application of 30 mM TEA blocked K+ currents through Kv2.1 by 87%. The same external concentration of TEA had no effect on Na+ currents through this channel. 4. As the K+ concentration was increased between 0 and 140 mM, the percentage of current blocked by TEA progressively increased from 0 to 87%. 5. These data indicate that block of K+ channels by external TEA depends on the permeating ion. Furthermore, these data indicate that in the presence of Na+ and absence of K+, TEA does not bind to the channel, and that addition of low concentrations of K+ facilitates TEA binding.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center