Key result
Treatment with 5 mM 4-Aminopyridine inhibited peak HERG current by ~59% and significantly prolonged action potentials in guinea-pig isolated ventricular myocytes.
Population
Mammalian cell line expressing HERG K+ channels and guinea-pig isolated ventricular myocytes
Design
Preclinical
Authors
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4-AP may confound ITO,1 studies at standard doses; leaves open HERG selectivity in cardiac electrophysiology research.
Effect estimate: IC50 4.4 +/- 0.5 mM
4-Aminopyridine, commonly used to study ITO,1, also blocks HERG K+ channels at millimolar concentrations, prolonging ventricular action potentials independently of ITO,1.
Ridley et al. (2003) studied this question. 4-Aminopyridine (4-AP) was evaluated on Inhibition of whole cell HERG current (IC50 4.4 +/- 0.5 mM). Treatment with 5 mM 4-Aminopyridine inhibited peak HERG current by ~59% and significantly prolonged action potentials in guinea-pig isolated ventricular myocytes.