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June 1, 1994The Journal of PhysiologyOpen Access

Regulation of the frequency‐dependent facilitation of L‐type Ca2+ currents in rat ventricular myocytes.

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Key result

Facilitation of L-type Ca2+ currents in rat ventricular myocytes reflects a voltage-driven interconversion of fast to slow current components, regulated by Ca2+ and cAMP-dependent phosphorylation.

Population

Rat ventricular myocytes

Comparison

Various pharmacological agents and stimulation… vs Baseline or control conditions

Design

Preclinical

Authors

FTFrançois TiahoInstitut de Recherche en Santé, Environnement et TravailCPChristophe PiotInterventional CardiologyJNJoël NargeotElectrophysiology

Discussion

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Implication

Extends mechanistic insight into L-type Ca2+ facilitation in rat myocytes; leaves open relevance to human ventricular physiology.

Key Points

  • This research aims to understand how stimulation frequency influences L-type Ca2+ currents in rat ventricular myocytes.
  • Used whole-cell patch-clamp technique at 1 Hz stimulation
  • Evaluated the effects of pharmacological agents like Ni2+, nifedipine, and Bay K 8644
  • Investigated the role of cAMP-dependent phosphorylation and Ca2+ modulation
  • Facilitation of L-type Ca2+ currents depended on a predominance of the fast current component (ICa,fc)
  • Ni2+ and nifedipine inhibited facilitation by targeting ICa,fc
  • When no EGTA was included in the patch pipette, facilitation decreased with Ba2+ replacing Ca2+ as the permeating ion

Structured PICO

P
Population
Rat ventricular myocytes
I
Intervention
Various pharmacological agents (Ni2+, nifedipine, isoprenaline, cAMP, C-sub, Bay K 8644, inhibitors of PKA, naphthalenesulphonamide, Ba2+, BAPTA) and stimulation rates (1 Hz trains) using whole-cell patch-clamp technique
C
Comparator
Baseline or control conditions (e.g., absence of agents, EGTA vs BAPTA, Ca2+ vs Ba2+)
O
Outcome
Facilitation of L-type Ca2+ currents (ICa) and current decay components (ICa,fc and ICa,sc)surrogate

The study demonstrates that frequency-dependent facilitation of L-type calcium currents in rat ventricular myocytes requires the fast current component and is regulated by intracellular calcium and cAMP-dependent phosphorylation.

Cite This Study

Tiaho et al. (1994) studied Rat ventricular myocytes. Increased rate of stimulation and pharmacological agents was evaluated on Facilitation of L-type Ca2+ currents (ICa). Facilitation of L-type Ca2+ currents in rat ventricular myocytes reflects a voltage-driven interconversion of fast to slow current components, regulated by Ca2+ and cAMP-dependent phosphorylation.

synapsesocial.com/papers/6a21cbf74c1bee377cecaecdhttps://doi.org/10.1113/jphysiol.1994.sp020187
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Also Consider

Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:

  1. 1Mechanism of the use dependence of Ca2+ current in guinea‐pig myocytes.1988 · 50 citations
  2. 2Calcium current in single cells isolated from normal and hypertrophied rat heart. Effects of beta-adrenergic stimulation.1990 · 148 citations
  3. 3Rate dependence of action potential duration and calcium current in isolated guinea‐pig cardiocytes1992 · 15 citations
  4. 4The calcium and frequency dependence of the slow inward current ‘staircase’ in frog atrium.1981 · 87 citations
  5. 5Time course of the increase in the myocardial slow inward current after a photochemically generated concentration jump of intracellular cAMP.1983 · 130 citations