Effect of GLG-V-13, a class III antiarrhythmic agent, on potassium currents in rabbit ventricular myocytes.
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-clamp 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 microM. At high concentration, the slow component of the delayed rectifier potassium current was also depressed by the drug (40% effect at 10 microM 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 microM 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.
Albert Szent-Györgyi Medical University, Department of Pharmacology and Pharmacotherapy, Szeged, Hungary.
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L
Virág
T
T
Fazekas
N
N
Iost
A
A
Varró
K D
KD
Berlin
B J
BJ
Scherlag
R
R
Lazzara
J G
JG
Pap
D015761:4-Aminopyridine / Q000494:pharmacology; D018528:ATP-Binding Cassette Transporters; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology*; D066298:In Vitro Techniques; D054086:KATP Channels; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects* / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying; D024683:Potassium Channels, Tandem Pore Domain; D011817:Rabbits
D018528:ATP-Binding Cassette Transporters; D000889:Anti-Arrhythmia Agents; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007093:Imidazoles; D054086:KATP Channels; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D024683:Potassium Channels, Tandem Pore Domain; C092520:uK-ATP-1 potassium channel; C095121:GLG-V 13; D015761:4-Aminopyridine