Referenced in: none

Automatically associated channels: Kv2.1

Title: Interactions of aminopyridines with potassium channels of squid axon membranes.

Authors: J Z Yeh, G S Oxford, C H Wu, T Narahashi

Journal, date & volume: Biophys. J., 1976 Jan , 16, 77-81

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/1244890

Abstract
The effects of aminopyridines on ionic conductances of the squid giant axon membrane were examined using voltage clamp and internal perfusion techniques. 4-Aminopyridine (4-AP) reduced potassium currents, but had no effect upon transient sodium currents. The block of potassium channels by 4-AP was substantially less with (a) strong depolarization to positive membrane potentials, (b) increasing the duration of a given depolarizing step, and (c) increasing the frequency of step depolarizations. Experiments with high external potassium concentrations revealed that the effect of 4-AP was independent of the direction of potassium ion movement. Both 3- and 2-aminopyridine were indistinguishable from 4-AP except in potency. It is concluded that aminopyrimidines may be used as tools to block the potassium conductance in excitable membranes, but only within certain specific voltage and frequency limits.