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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

Clarithromycin reduces Isus and Ito currents in human atrial myocytes with minor repercussions on action potential

Pascale Gluais1, Michèle Bastide, Daniel Grandmougin

  • 1Laboratoire de Pharmacologie, Faculté de Médecine Henri Warembourg, Pole Recherche, 1 place de Verdun, 59045 Lille Cedex, France. pascale_gluais@yahoo.fr

Fundamental & Clinical Pharmacology
|March 16, 2004
PubMed

Insights

The antibiotic clarithromycin prolongs action potential duration in human atrial cells by affecting specific ion currents. These direct cardiac effects may increase the risk of arrhythmias.

Area of Science:

  • Cardiology
  • Pharmacology
  • Electrophysiology

Background:

  • Macrolide antibacterial clarithromycin is known to cause QT interval prolongation.
  • Previous studies in rabbits showed clarithromycin lengthens action potential duration and blocks delayed rectifier current.

Purpose of the Study:

  • Investigate clarithromycin's effects on human atrial myocytes' ion currents (Ca2+ L-type, K+ repolarizing).
  • Assess clarithromycin's impact on action potentials in human atrial and ventricular myocardium.

Main Methods:

  • Whole-cell patch clamp recordings on human atrial myocytes.
  • Conventional microelectrode recordings from human atrial and ventricular myocardium.

Main Results:

  • Clarithromycin (10-30 microM) significantly reduced sustained outward K+ current (Isus).
  • A 100 microM concentration of clarithromycin reduced transient outward K+ current (Ito); calcium current was unaffected.
  • Clarithromycin (10-100 microM) prolonged action potential duration in atrial tissue but not ventricular tissue.

Conclusions:

  • Clarithromycin has direct cardiac electrophysiological effects.
  • These effects on ion currents and action potentials may contribute to clarithromycin's pro-arrhythmic potential.

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