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Naunyn Schmiedebergs Arch Pharmacol. 2016 Jul;389(7):713-21. doi: 10.1007/s00210-016-1232-8. Epub 2016 Mar 31.

The class III anti-arrhythmic agent, amiodarone, inhibits voltage-dependent K(+) channels in rabbit coronary arterial smooth muscle cells.

Author information

1
Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, 1 Kangwondaehak-gil, Chuncheon, 200-701, South Korea.
2
Department of Biomedical Engineering, and Center for Marine-Integrated Biomedical Technology (BK21 Plus), Pukyong National University, Busan, 608-737, South Korea.
3
Department of Molecular and Cellular Biochemistry, Kangwon National University School of Medicine, Chuncheon, 200-701, South Korea.
4
Department of Medical Environmental Biology and Tropical Medicine, Kangwon National University School of Medicine, Chuncheon, 200-701, South Korea.
5
Institute of Medical Sciences, Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, 200-701, South Korea.
6
Department of Pulmonary, Critical Care and Sleep Medicine, University of Southern California, Keck School of Medicine, Los Angeles, CA, 90033, USA.
7
Department of Physiology, Konkuk University School of Medicine, Chungju, 380-701, South Korea.
8
Department of Microbiology, Inje University College of Medicine, Busan, 614-735, South Korea. cihima@inje.ac.kr.
9
Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, 1 Kangwondaehak-gil, Chuncheon, 200-701, South Korea. parkws@kangwon.ac.kr.

Abstract

We examined the inhibitory effect of amiodarone, a class III anti-arrhythmic agent, on voltage-dependent K(+) (Kv) currents in freshly isolated rabbit coronary arterial smooth muscle cells, using a whole-cell patch clamp technique. Amiodarone inhibited Kv currents in a concentration-dependent manner, with a half-maximal inhibitory concentration (IC50) value of 3.9 ± 1.44 μM and a Hill coefficient of 0.45 ± 0.14. Amiodarone did not have a significant effect on the steady-state activation of Kv channels, but shifted the inactivation current toward a more negative potential. Application of consecutive pulses progressively augmented the amiodarone-induced Kv channel inhibition. Another class III anti-arrhythmic agent, dofetilide, did not inhibit the Kv current or change the inhibitory effect of amiodarone on Kv channels. Therefore, these results strongly suggest that amiodarone inhibits Kv currents in a concentration- and state-dependent manner.

KEYWORDS:

Amiodarone; Coronary artery; Voltage-dependent K+ channel

PMID:
27030392
DOI:
10.1007/s00210-016-1232-8
[Indexed for MEDLINE]

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