Effect of GLG-V-13, a class III antiarrhythmic agent, on potassium currents in rabbit ventricular myocytes

Virág, László and Fazekas, Tamás and Iost, Norbert and Varró, András and Berlin, K.Darrell and Scherlag, Benjamin J. and Lazzara, Ralph and Papp, Julius Gy. (2000) Effect of GLG-V-13, a class III antiarrhythmic agent, on potassium currents in rabbit ventricular myocytes. Life Sciences, 66 (17). PL253-PL258. ISSN 0024-3205

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Abstract

The effects of a new Class III antiarrhythmic drug, GLG-V-13, on the 4-aminopyridine sensitive transient outward current, on the inward rectifier potassium current, on the ATP sensitive potassium current and on the rapid and slow components of the delayed rectifier potassium current were studied in single rabbit ventricular myocytes using the whole-cell voltage-damp technique. GLG-V-13 blocked the rapid component of the delayed rectifier potassium current in a dose-dependent manner, with an estimated EC50 value of 0.36 mu M. At high concentration, the slow component of the delayed rectifier potassium current was also depressed by the drug (40% effect at 10 mu M concentration). The transient outward current, the inward rectifier potassium current and the ATP sensitive potassium current were not influenced by GLG-V-13, even at 10 mu M concentration. Thus, GLG-V-13 blocks predominantly the rapid component of the delayed rectifier potassium current which may play a significant role in the prolongation of repolarization by the drug in ventricular tissue.

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