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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

Effect of alpha-allocryptopine on transient outward potassium current in rabbit ventricular myocytes

Y Li1, S Wang, Y Liu

  • 1Electrophysiology of Laboratory, Institute of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, China.

Cardiology
|April 25, 2008
PubMed

Insights

Alpha-allocryptopine inhibits the transient outward potassium current (I(to)) in rabbit heart cells. This blocking effect on I(to) may explain its antiarrhythmic properties.

Area of Science:

  • Cardiology
  • Pharmacology
  • Electrophysiology

Background:

  • The transient outward potassium current (I(to)) plays a crucial role in cardiac repolarization.
  • Understanding the modulators of I(to) is essential for developing antiarrhythmic therapies.

Purpose of the Study:

  • To elucidate the mechanism by which alpha-allocryptopine inhibits I(to) in rabbit left-ventricular myocytes.
  • To investigate the concentration-dependent and use-independent effects of alpha-allocryptopine on I(to).

Main Methods:

  • Isolated rabbit left-ventricular myocytes were used.
  • The whole-cell patch-clamp technique was employed to record I(to).
  • Alpha-allocryptopine was applied at concentrations ranging from 1 to 100 microM.

Main Results:

  • Alpha-allocryptopine significantly decreased I(to) amplitude and density in a concentration-dependent manner (IC(50) = 37 +/- 8 microM).
  • The drug reduced I(to) inactivation time constants and altered the inactivation curve slope without affecting activation parameters.
  • Allocryptopine decreased transmural heterogeneity and dispersion of I(to) in the ventricular myocytes.

Conclusions:

  • Alpha-allocryptopine exhibits a direct blocking effect on I(to) in cardiac myocytes.
  • This inhibition of I(to) is a potential mechanism underlying the antiarrhythmic effects of alpha-allocryptopine.
Abstract

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