What question did this study set out to answer?

To characterize the electrophysiological and pharmacological properties of cloned rat Kv4.3 expressed in HEK293 cells and compare them directly to native transient outward potassium currents in rat ventricular myocytes.

January 1, 1999Cardiovascular ResearchOpen Access

Characterisation of Kv4.3 in HEK293 cells: comparison with the rat ventricular transient outward potassium current

View Full Paper

Ask AI

Bookmark

To characterize the electrophysiological and pharmacological properties of cloned rat Kv4.3 expressed in HEK293 cells and compare them directly to native transient outward potassium currents in rat ventricular myocytes.
Cloned rat Kv4.3 cDNA into the pHook2 mammalian expression vector and transiently expressed the construct in HEK293 cells.
Performed whole-cell patch-clamp recordings to evaluate voltage-dependent gating, inactivation kinetics, recovery rates, and sensitivity to 4-aminopyridine in comparison to native rat ventricular myocytes.
Recombinant Kv4.3 activated positive to -40 mV with steady-state half-inactivation at -47.4 ± 0.3 mV (slope 5.9 ± 0.2 mV), whereas native Ito activated positive to -20 mV with half-inactivation at -29.1 ± 0.7 mV (slope 4.5 ± 0.5 mV).
Recovery from inactivation was significantly slower for Kv4.3 (time constant 213.2 ± 4.1 ms) than for native Ito (23.0 ± 1.5 ms), and native Ito showed tenfold higher sensitivity to 4-aminopyridine (half-maximal inhibitory concentration 0.14 ± 0.02 mM vs. 1.54 ± 0.13 mM).
Kv4.3 mRNA expression was higher in atria than in ventricles but demonstrated a homogeneous distribution across the ventricular myocardium.

Structured PICO

Population

HEK293 cells transfected with rat Kv4.3 potassium channel and native rat ventricular myocytes

Intervention

Patch clamp experiments characterizing electrophysiological parameters of Kv4.3

Comparator

Native rat ventricular myocyte Ito current

Outcome

Electrophysiological parameters (activation, steady-state inactivation, recovery from inactivation, and pharmacological sensitivity to 4-aminopyridine)surrogate

The Kv4.3 channel likely plays a major role in the molecular structure of the rat cardiac Ito current, and its homogeneous distribution across the ventricle suggests specific blockers may not alter normal Ito heterogeneity.

Discussion

No takes yet. Share an insight, caveat, or question.

Implication

Kv4.3 may contribute to rat ventricular Ito; leaves open translation to human electrophysiology or selective blockers.

Cite This Study

Jean‐François Faivre (1999) studied this question.

synapsesocial.com/papers/6a8ab8231fb56efa37d4b97a https://doi.org/10.1016/s0008-6363(98)00215-6

View Full Paper

Ask AI

Bookmark

Characterisation of Kv4.3 in HEK293 cells: comparison with the rat ventricular transient outward potassium current

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Characterisation of Kv4.3 in HEK293 cells: comparison with the rat ventricular transient outward potassium current

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

Also Consider