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Comparison of HERG channel blocking effects of various beta-blockers-- implication for clinical strategy

Kazunobu Kawakami1, Toshihisa Nagatomo, Haruhiko Abe

  • 1Second Department of Internal Medicine, University of Occupational and Environmental Health Japan, 1-1 Iseigaoka, Kitakyushu 807-8555, Japan.

British Journal of Pharmacology
|November 30, 2005
PubMed

Insights

Beta-blockers affect HERG channels, with carvedilol and propranolol showing significant inhibition. Atenolol and metoprolol may be safer for long QT syndrome patients, while carvedilol

Area of Science:

  • Pharmacology
  • Cardiovascular Science
  • Molecular Biology

Background:

  • Beta-blockers are crucial for cardiovascular disease treatment.
  • Their precise impact on HERG channels requires further elucidation.
  • Understanding drug-channel interactions is vital for patient safety.

Purpose of the Study:

  • To investigate the direct effects of beta-blockers on HERG current.
  • To determine the molecular basis of beta-blocker binding to HERG channels.
  • To assess the clinical implications for long QT syndrome patients.

Main Methods:

  • Stable expression of wild-type and mutant HERG channels (Y652A, F656C) in HEK293 cells.
  • Whole-cell patch-clamp technique to record HERG current at 23°C.
  • Concentration-dependent inhibition assays and frequency-dependence analysis.

Main Results:

  • Carvedilol, propranolol, and ICI 118551 inhibited HERG current in a concentration-dependent manner.
  • Mutations Y652A and F656C partially attenuated the inhibitory effects of carvedilol, propranolol, and ICI 118551.
  • Atenolol and metoprolol showed minimal to no HERG channel inhibition at relevant concentrations.
  • No frequency-dependent block was observed for any beta-blocker.

Conclusions:

  • Beta-blocker affinities for HERG channels vary significantly.
  • Atenolol and metoprolol are potentially safer choices for long QT syndrome patients.
  • Carvedilol's HERG channel interaction may contribute to its Class III antiarrhythmic properties and favorable clinical outcomes.

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