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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

T-type calcium currents in rat cardiomyocytes during postnatal development: contribution to hormone secretion

V Leuranguer1, A Monteil, E Bourinet

  • 1Physiopathologie des Canaux Ioniques, Institut de Génétique Humaine-Centre National de la Recherche Scientifique (CNRS) UPR 1142, 34396 Montpellier cedex 05, France.

American Journal of Physiology. Heart and Circulatory Physiology
|October 25, 2000
PubMed

Insights

Neonatal T-type calcium channels (I(Ca,T)) in rat hearts are primarily linked to the alpha(1G)-subunit. These channels significantly influence atrial natriuretic factor secretion and calcium signaling in early development.

Area of Science:

  • Cardiovascular Physiology
  • Molecular Cardiology
  • Ion Channel Biology

Background:

  • T-type Ca(2+) channels are implicated in cardiac functions like automaticity and remodeling.
  • The specific isoforms responsible for cardiac T-type Ca(2+) current (I(Ca,T)) remain unidentified.

Purpose of the Study:

  • To characterize the postnatal development and functional properties of cardiac I(Ca,T).
  • To identify the molecular correlate of I(Ca,T) in neonatal rat cardiomyocytes.
  • To investigate the role of I(Ca,T) in atrial natriuretic factor (ANF) secretion.

Main Methods:

  • Patch-clamp electrophysiology on freshly dissociated rat atrial and ventricular myocytes.
  • RT-PCR to analyze gene expression of Ca(2+) channel subtypes.
  • Measurement of ANF secretion using peptide radioimmunoassays.

Main Results:

  • I(Ca,T) density evolves postnatally in rat atrial and ventricular myocytes.
  • Neonatal I(Ca,T) exhibits characteristic kinetics and is poorly sensitive to Ni(2+).
  • Functional properties and RT-PCR suggest neonatal I(Ca,T) involves the alpha(1G)-subunit.
  • I(Ca,T) significantly contributes to ANF secretion and Ca(2+) signaling in neonates.

Conclusions:

  • The alpha(1G)-subunit is likely the primary component of cardiac I(Ca,T) during the neonatal period.
  • Cardiac I(Ca,T) plays a crucial role in neonatal atrial function and calcium signaling pathways.

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