Prevailing Effects of Ibutilide on Fast Delayed Rectifier K+ Channel.
J Membr Biol
; 252(6): 609-616, 2019 12.
Article
em En
| MEDLINE
| ID: mdl-31584122
ABSTRACT
Effects of ibutilide, a class III antiarrhythmic drug, on delayed rectifier potassium currents (IK) in freshly isolated guinea pig ventricular myocytes were studied. Experiments were performed using the whole-cell configuration of patch-clamp technique under blockade of L-type calcium currents (Cav1). Ibutilide at concentrations ranging between 10 nM and 100 µM inhibited IKr in dose-dependent manner with a half maximal effective concentration of 2.03 ± 0.74 µM (n = 5-10). The amplitude of tail currents activated by prepulse to + 20 mV was decreased from 253 ± 52 to 130 ± 25 pA (n = 8, p < 0.01) in the presence of 1 µM ibutilide. The envelope test revealed time-dependent changes in ratio of IK-tail/ΔIK during 0.2-2 s pulse durations in the absence of drug. With ibutilide, regardless of pulse duration, a relatively constant ratio was estimated, indicative of predominant involvement of IKr component. The slow IKs persisted to greater extent even at 100 µM ibutilide revealing a distinguishable selectivity toward the IKr component.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sulfonamidas
/
Canais de Potássio
Limite:
Animals
Idioma:
En
Revista:
J Membr Biol
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Alemanha