Pharmacological activation of rapid delayed rectifier potassium current suppresses bradycardia-induced triggered activity in the isolated guinea pig heart.

TY - JOUR

T1 - Pharmacological activation of rapid delayed rectifier potassium current suppresses bradycardia-induced triggered activity in the isolated guinea pig heart.

AU - Hansen, Rie Schultz

AU - Olesen, Søren-Peter

AU - Grunnet, Morten

N1 - Keywords: Action Potentials; Animals; Anti-Arrhythmia Agents; Bradycardia; Electrocardiography; Ether-A-Go-Go Potassium Channels; Guinea Pigs; Heart; Heart Rate; Perfusion; Phenylurea Compounds; Piperidines; Pyridines; Tetrazoles; Ventricular Function

PY - 2007

Y1 - 2007

N2 - Recently, attention has been drawn to compounds that activate the human ether-a-go-go channel potassium channel (hERG), which is responsible for the repolarizing rapid delayed rectifier potassium current (I(Kr)) in the mammalian myocardium. The compound NS3623 [N-(4-bromo-2-(1H-tetrazol-5-yl)-phenyl)-N'-(3'-trifluoromethylphenyl) urea] increases the macroscopic current conducted by the hERG channels by increasing the time constant for channel inactivation, which we have reported earlier. In vitro studies suggest that pharmacological activation is an attractive approach for the treatment of some arrhythmias. We present here data that support that NS3623 affects native I(Kr) and report the effects that activating this potassium current have in the intact guinea pig heart. In Langendorff-perfused hearts, the compound showed a concentration-dependent shortening of action potential duration, which was also detected as concentration-dependent shorter QT intervals. There was no sign of action potential triangulation or reverse use dependence. NS3623 decreased QT variability and distinctly decreased the occurrence of extrasystoles in the acutely bradypaced hearts. Taken together, the present data strongly support the concept of using hERG activators as a treatment for certain kinds of arrhythmias and suggest further investigation of this new approach.

AB - Recently, attention has been drawn to compounds that activate the human ether-a-go-go channel potassium channel (hERG), which is responsible for the repolarizing rapid delayed rectifier potassium current (I(Kr)) in the mammalian myocardium. The compound NS3623 [N-(4-bromo-2-(1H-tetrazol-5-yl)-phenyl)-N'-(3'-trifluoromethylphenyl) urea] increases the macroscopic current conducted by the hERG channels by increasing the time constant for channel inactivation, which we have reported earlier. In vitro studies suggest that pharmacological activation is an attractive approach for the treatment of some arrhythmias. We present here data that support that NS3623 affects native I(Kr) and report the effects that activating this potassium current have in the intact guinea pig heart. In Langendorff-perfused hearts, the compound showed a concentration-dependent shortening of action potential duration, which was also detected as concentration-dependent shorter QT intervals. There was no sign of action potential triangulation or reverse use dependence. NS3623 decreased QT variability and distinctly decreased the occurrence of extrasystoles in the acutely bradypaced hearts. Taken together, the present data strongly support the concept of using hERG activators as a treatment for certain kinds of arrhythmias and suggest further investigation of this new approach.

U2 - 10.1124/jpet.106.118448

DO - 10.1124/jpet.106.118448

M3 - Journal article

C2 - 17325228

SN - 0022-3565

VL - 321

SP - 996

EP - 1002

JO - Journal of Pharmacology and Experimental Therapeutics

JF - Journal of Pharmacology and Experimental Therapeutics

IS - 3

ER -