SALICYLALDOXIME BLOCKS K+ AND CA2+ CURRENTS IN RAT CARDIAC MYOCYTES

The effects of salicylaldoxime, 2-(OH)C6H4CH = NOH, on the action pote ntial duration, transient outward K+ current and slow inward Ca2+ curr ent were studied in isolated rat ventricular myocytes. The application of salicylaldoxime (0.1-2.0 mM) reversibly increased the action poten tial duration and reduced in a dose-dependent manner both the transien t outward K+ and the slow inward Ca2+ currents. The effect of salicyla ldoxime on these two ionic currents was similar to that of 2,3-butaned ione monoxime, but was about ten times more potent. Compounds which bl ock both K+ and Ca2+ currents may represent a new type of Class III an tiarrhythmic agent which counteracts arrhythmias initiated by re-entry with reduced proarrhythmic risk via triggered activity.