Open AccessEffects of Sematilide, a Novel Class III Antiarrhythmic Agent, on Delayed Rectifier K+ Current in Guinea Pig Atrial Myocytes
Author(s) -
Yasunori Ishii,
Katsuhiko Muraki,
Atsushi Kurihara,
Yuji Imaizumi,
Minoru Watanabe
Publication year - 1996
Publication title -
japanese journal of pharmacology/japanese journal of pharmacology
Language(s) - English
Resource type - Journals
eISSN - 1347-3506
pISSN - 0021-5198
DOI - 10.1254/jjp.71.361
Subject(s) - guinea pig , refractory period , depolarization , inward rectifier potassium ion channel , myocyte , chemistry , voltage clamp , repolarization , medicine , electrophysiology , patch clamp , biophysics , cardiology , pharmacology , endocrinology , biology , ion channel , receptor
Effects of sematilide, a novel class III antiarrhythmic agent, on the delayed rectifier K+ current (Ik) were examined in guinea pig atrial myocytes using a voltage clamp technique. Sematilide inhibited both time-dependent outward current upon depolarization and tail currents (Ik-tail) at -40 mV. The concentration of sematilide required for a 50% decrease in Ik-tail was approximately 50 microM. The sematilide-sensitive current obtained using a triangular voltage command exhibited marked inward rectification and had the maximum amplitude at -30 mV. These results suggest that sematilide inhibits rapidly activating Ik in guinea pig atrial myocytes, resulting in the prolongation of action potential duration and refractoriness.