TY - JOUR

T1 - Pharmacological activation of Kv11.1 in transgenic long QT-1 rabbits

AU - Bentzen, Bo Hjorth

AU - Bahrke, Sophia

AU - Wu, Kezhong

AU - Larsen, Anders Peter

AU - Odening, Katja E

AU - Franke, Gerlind

AU - Storm vans Gravesande, Karin

AU - Biermann, Jürgen

AU - Peng, Xuwen

AU - Koren, Gideon

AU - Zehender, Manfred

AU - Bode, Christoph

AU - Grunnet, Morten

AU - Brunner, Michael

PY - 2011/2

Y1 - 2011/2

N2 - Transgenic rabbits expressing pore mutants of K(V)7.1 display a long QT syndrome 1 (LQT1) phenotype. Recently, NS1643 has been described to increase I(Kr).We hypothesized that NS1643 would shorten the action potential duration (APD(90)) in LQT1 rabbits. Transgenic LQT1 rabbits were compared with littermate control (LMC) rabbits. In vivo electrocardiogram studies in sedated animals were performed at baseline and during 45 minutes of intravenous infusion of NS1643 or vehicle in a crossover design. Ex vivo monophasic action potentials were recorded from Langendorff-perfused hearts at baseline and during 45-minute perfusion with NS1643. Left ventricular refractory periods were assessed before and after NS1643 infusion. Genotype differences in APD accommodation were also addressed. In vivo NS1643 shortened the QTc significantly in LQT1 compared with vehicle. In Langendorff experiments, NS1643 significantly shortened the APD(90) in LQT1 and LMC [32.0 ± 4.3 milliseconds (ms); 21.0 ± 5.0 ms] and left ventricular refractory periods (23.7 ± 8.3; 22.6 ± 9.9 ms). NS1643 significantly decreased dp/dt (LQT1: 49% ± 3%; LMC: 63% ± 4%) and increased the incidence of arrhythmia. The time course of APD adaptation was impaired in LQT1 rabbits and unaffected by I(Kr) augmentation. In conclusion, K(V)11.1 channel activation shortens the cardiac APD in a rabbit model of inherited LQT1, but it comes with the risk of excessive shortening of APD.

AB - Transgenic rabbits expressing pore mutants of K(V)7.1 display a long QT syndrome 1 (LQT1) phenotype. Recently, NS1643 has been described to increase I(Kr).We hypothesized that NS1643 would shorten the action potential duration (APD(90)) in LQT1 rabbits. Transgenic LQT1 rabbits were compared with littermate control (LMC) rabbits. In vivo electrocardiogram studies in sedated animals were performed at baseline and during 45 minutes of intravenous infusion of NS1643 or vehicle in a crossover design. Ex vivo monophasic action potentials were recorded from Langendorff-perfused hearts at baseline and during 45-minute perfusion with NS1643. Left ventricular refractory periods were assessed before and after NS1643 infusion. Genotype differences in APD accommodation were also addressed. In vivo NS1643 shortened the QTc significantly in LQT1 compared with vehicle. In Langendorff experiments, NS1643 significantly shortened the APD(90) in LQT1 and LMC [32.0 ± 4.3 milliseconds (ms); 21.0 ± 5.0 ms] and left ventricular refractory periods (23.7 ± 8.3; 22.6 ± 9.9 ms). NS1643 significantly decreased dp/dt (LQT1: 49% ± 3%; LMC: 63% ± 4%) and increased the incidence of arrhythmia. The time course of APD adaptation was impaired in LQT1 rabbits and unaffected by I(Kr) augmentation. In conclusion, K(V)11.1 channel activation shortens the cardiac APD in a rabbit model of inherited LQT1, but it comes with the risk of excessive shortening of APD.

KW - Action Potentials

KW - Animals

KW - Animals, Genetically Modified

KW - Cresols

KW - Cross-Over Studies

KW - Ether-A-Go-Go Potassium Channels

KW - Female

KW - Long QT Syndrome

KW - Phenylurea Compounds

KW - Rabbits

KW - Random Allocation

U2 - 10.1097/FJC.0b013e318203a44d

DO - 10.1097/FJC.0b013e318203a44d

M3 - Journal article

C2 - 21135701

VL - 57

SP - 223

EP - 230

JO - Journal of Cardiovascular Pharmacology

JF - Journal of Cardiovascular Pharmacology

SN - 0160-2446

IS - 2

ER -