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Updated: Aug 11, 2026

Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
10:53

Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents

Published on: July 3, 2013

Alosetron and the rapid component of delayed rectifying potassium current in cardiac cells

A Carl1, K M Sanders, J L Kenyon

  • 1Department of Physiology & Cell Biology, University of Nevada School of Medicine, Reno 89557, USA. andreas@physio.unr.edu

Life Sciences
|March 27, 2001
PubMed

Insights

Alosetron, a 5-hydroxytryptamine receptor antagonist, does not block cardiac potassium currents (I(Kr)) or I(Ks). Therefore, alosetron use for irritable bowel syndrome (IBS) is unlikely to cause long QT syndrome.

Area of Science:

  • Cardiovascular pharmacology
  • Gastroenterology
  • Ion channel physiology

Background:

  • Some drugs targeting 5-hydroxytryptamine receptors can inhibit cardiac potassium currents (I(Kr)).
  • This inhibition prolongs the QT interval, potentially causing fatal arrhythmias.
  • Alosetron is a novel 5-hydroxytryptamine type 3 (5HT3) receptor antagonist for irritable bowel syndrome (IBS).

Purpose of the Study:

  • To investigate whether alosetron blocks the rapid component of delayed rectifying potassium currents (I(Kr)) in cardiac myocytes.
  • To assess the potential risk of alosetron-induced long QT syndrome.

Main Methods:

  • Whole-cell voltage clamp technique was used to isolate I(Kr) in guinea pig cardiac myocytes.
  • I(Kr) was identified by its sensitivity to the selective antagonist E4031.
  • The effects of cisapride and varying concentrations of alosetron on I(Kr) and I(Ks) were examined.

Main Results:

  • Cisapride (10(-6) M) significantly inhibited the E4031-sensitive current.
  • Alosetron (10(-10)-10(-6) M) did not inhibit I(Kr).
  • Alosetron also did not inhibit the related potassium current, I(Ks).

Conclusions:

  • Alosetron does not block cardiac potassium currents I(Kr) or I(Ks).
  • The use of alosetron for IBS treatment is not expected to be associated with long QT syndrome.
  • These findings suggest a favorable cardiac safety profile for alosetron regarding ion channel effects.

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