Blockage of the HERG human cardiac K+ channel by the gastrointestinal prokinetic agent cisapride

Saeed Mohammad, Zhengfeng Zhou, Qiuming Gong, Craig T. January

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Abstract

Cisapride, a gastrointestinal prokinetic agent, is known to cause long Q-T syndrome and ventricular arrhythmias. The cellular mechanism is not known. The human ether-a-go-go-related gene (HERG), which encodes the rapidly activating delayed rectifier K+ current and is important in cardiac repolarization, may serve as a target for the action of cisapride. We tested the hypothesis that cisapride blocks HERG. The whole cell patch-clamp recording technique was used to study HERG channels stably expressed heterologously in HEK293 cells. Under voltage-clamp conditions, cisapride block of HERG is dose dependent with a half-maximal inhibitory concentration of 6.5 nM at 22°C (n = 25 cells). Currents rapidly recovered with drug washout. The onset of block by cisapride required channel activation indicative of open or inactivated state blockage. Block of HERG with cisapride after channel activation was voltage dependent. At -20 mV, 10 nM cisapride reduced HERG tail-current amplitude by 5%, whereas, at +20 mV, the tail-current amplitude was reduced by 45% (n = 4 cells). At -20 and +20 mV, 100 nM cisapride reduced tail-current amplitude by 66 and 90%, respectively. We conclude that cisapride is a potent blocker of HERG channels expressed in HEK293 cells. This effect may account for the clinical occurrence of Q-T prolongation and ventricular arrhythmias observed with cisapride. rapidly activating delayed-rectifier potassium current; potassium channels; Q-T interval; torsades de pointes; gastrointestinal motility

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume42
Issue number5
StatePublished - 1997
Externally publishedYes

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Cisapride
Gastrointestinal Agents
Ether
Genes
Tail
HEK293 Cells
Cardiac Arrhythmias
Torsades de Pointes
Gastrointestinal Motility
Potassium Channels
Patch-Clamp Techniques
Potassium

ASJC Scopus subject areas

  • Physiology

Cite this

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title = "Blockage of the HERG human cardiac K+ channel by the gastrointestinal prokinetic agent cisapride",
abstract = "Cisapride, a gastrointestinal prokinetic agent, is known to cause long Q-T syndrome and ventricular arrhythmias. The cellular mechanism is not known. The human ether-a-go-go-related gene (HERG), which encodes the rapidly activating delayed rectifier K+ current and is important in cardiac repolarization, may serve as a target for the action of cisapride. We tested the hypothesis that cisapride blocks HERG. The whole cell patch-clamp recording technique was used to study HERG channels stably expressed heterologously in HEK293 cells. Under voltage-clamp conditions, cisapride block of HERG is dose dependent with a half-maximal inhibitory concentration of 6.5 nM at 22°C (n = 25 cells). Currents rapidly recovered with drug washout. The onset of block by cisapride required channel activation indicative of open or inactivated state blockage. Block of HERG with cisapride after channel activation was voltage dependent. At -20 mV, 10 nM cisapride reduced HERG tail-current amplitude by 5{\%}, whereas, at +20 mV, the tail-current amplitude was reduced by 45{\%} (n = 4 cells). At -20 and +20 mV, 100 nM cisapride reduced tail-current amplitude by 66 and 90{\%}, respectively. We conclude that cisapride is a potent blocker of HERG channels expressed in HEK293 cells. This effect may account for the clinical occurrence of Q-T prolongation and ventricular arrhythmias observed with cisapride. rapidly activating delayed-rectifier potassium current; potassium channels; Q-T interval; torsades de pointes; gastrointestinal motility",
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T1 - Blockage of the HERG human cardiac K+ channel by the gastrointestinal prokinetic agent cisapride

AU - Mohammad, Saeed

AU - Zhou, Zhengfeng

AU - Gong, Qiuming

AU - January, Craig T.

PY - 1997

Y1 - 1997

N2 - Cisapride, a gastrointestinal prokinetic agent, is known to cause long Q-T syndrome and ventricular arrhythmias. The cellular mechanism is not known. The human ether-a-go-go-related gene (HERG), which encodes the rapidly activating delayed rectifier K+ current and is important in cardiac repolarization, may serve as a target for the action of cisapride. We tested the hypothesis that cisapride blocks HERG. The whole cell patch-clamp recording technique was used to study HERG channels stably expressed heterologously in HEK293 cells. Under voltage-clamp conditions, cisapride block of HERG is dose dependent with a half-maximal inhibitory concentration of 6.5 nM at 22°C (n = 25 cells). Currents rapidly recovered with drug washout. The onset of block by cisapride required channel activation indicative of open or inactivated state blockage. Block of HERG with cisapride after channel activation was voltage dependent. At -20 mV, 10 nM cisapride reduced HERG tail-current amplitude by 5%, whereas, at +20 mV, the tail-current amplitude was reduced by 45% (n = 4 cells). At -20 and +20 mV, 100 nM cisapride reduced tail-current amplitude by 66 and 90%, respectively. We conclude that cisapride is a potent blocker of HERG channels expressed in HEK293 cells. This effect may account for the clinical occurrence of Q-T prolongation and ventricular arrhythmias observed with cisapride. rapidly activating delayed-rectifier potassium current; potassium channels; Q-T interval; torsades de pointes; gastrointestinal motility

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