Advertisement

Basic Research in Cardiology

, Volume 98, Issue 6, pp 362–366 | Cite as

A hyperpolarization activated inward current (If) is present in infant ventricular myocytes

  • Klaus Zorn-Pauly
  • Peter Schaffer
  • Brigitte Pelzmann
  • Eva Bernhart
  • Petra Lang
  • Michael Zink
  • Heinrich Mächler
  • Bruno Rigler
  • Bernd KoidlEmail author
ORIGINAL CONTRIBUTION

Abstract.

If was shown to be present in adult human atrial and ventricular myocytes but data obtained from infant myocytes are lacking. We have studied If in isolated ventricular myocytes from children undergoing surgical correction of tetralogy of Fallot (TOF; n = 5; mean age: 15.3 months). All recordings were made with the patch clamp technique in the whole cell mode at a temperature of 36–37 °C. A modified Tyrode solution containing 25 mM KCl was used to amplify If. Considering If to be present when its current density at –120 mV was greater than 0.5 pA/pF, If could be found in 28 out of 32 myocytes (88%). The mean current density was –2.01 ± 0.3 pA/pF (mean ± S.E.M.). First current activation occurred at –70 mV and If could be reversibly inhibited by superfusing the myocytes with CsCl (2 mM). Half maximal activation (V1/2) of If was at –80.3 ± 1.0 mV (n = 28). Beta-adrenergic receptor stimulation with isoproterenol (1 µM) caused an acceleration of current activation and a shift of V1/2 by 7.88 ± 1.8 mV (n = 10) to less negative potentials. This study provides first evidence that the hyperpolarization-activated pacemaker current If is present in infant human ventricular myocytes. Our results suggest that If in ventricle of infants suffering from TOF has similar properties as If in adult ventricle.

Key words

Infant ventricular myocytes tetralogy of Fallot patch clamp ion channel pacemaker current 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Steinkopff Verlag 2003

Authors and Affiliations

  • Klaus Zorn-Pauly
    • 1
  • Peter Schaffer
    • 1
  • Brigitte Pelzmann
    • 1
  • Eva Bernhart
    • 1
  • Petra Lang
    • 1
  • Michael Zink
    • 2
  • Heinrich Mächler
    • 3
  • Bruno Rigler
    • 3
  • Bernd Koidl
    • 1
    Email author
  1. 1.Institut für Medizinische Physik und BiophysikUniversität GrazGrazAustria
  2. 2.Universitätsklinik für Anästhesiologie und IntensivmedizinUniversität GrazGrazAustria
  3. 3.Universitätsklinik für ChirugieUniversität GrazGrazAustria

Personalised recommendations