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Updated: Aug 13, 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

Imipramine blocks the transient outward potassium current in rat ventricular myocytes

Q Y Liu1, X L Wang

  • 1Department of Pharmacology, Chinese Academy of Medical Sciences, Beijing, China.

Zhongguo Yao Li Xue Bao = Acta Pharmacologica Sinica
|July 1, 1997
PubMed

Insights

Imipramine inhibits transient outward potassium current (I(to)) in rat heart cells. This drug acts in a concentration-dependent manner, suggesting potential therapeutic applications for certain heart conditions.

Area of Science:

  • Cardiology
  • Pharmacology
  • Electrophysiology

Background:

  • Transient outward potassium current (I(to)) plays a crucial role in cardiac repolarization.
  • Understanding the effects of pharmaceutical compounds on ion channels is vital for drug development.

Purpose of the Study:

  • To investigate the impact of imipramine on I(to) in rat ventricular myocytes.
  • To determine the concentration-dependent effects and voltage-dependence of imipramine's interaction with I(to).

Main Methods:

  • Utilized patch-clamp whole-cell recording techniques for precise electrophysiological measurements.
  • Applied varying concentrations of imipramine to assess its inhibitory effects on I(to).

Main Results:

  • Imipramine demonstrated a concentration-dependent inhibition of I(to) with an IC50 of 6.0 µmol/L.
  • The drug accelerated I(to) inactivation and exhibited voltage-independent blocking properties.
  • Imipramine showed a tendency to prolong I(to) recovery from inactivation, though not statistically significant.

Conclusions:

  • Imipramine effectively blocks I(to) in a concentration-dependent and voltage-independent manner.
  • The findings suggest an "open channel blocking" mechanism for imipramine's interaction with I(to).
  • These results provide insights into the electrophysiological effects of imipramine on cardiac ion channels.
Abstract

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