Tags

Type your tag names separated by a space and hit enter

Depressed transient outward current in single hypertrophied cardiomyocytes isolated from the right ventricle of ferret heart.
Cardiovasc Res. 1995 Sep; 30(3):440-8.CR

Abstract

OBJECTIVE

The aim of this study was to investigate transient outward potassium current (Ito) changes as a basis for the prolongation of the action potential associated with cardiac hypertrophy.

METHODS

Right ventricular hypertrophy was induced by chronic pulmonary artery constriction in adult male ferrets. After 4-6 weeks, hearts were excised and single myocytes were isolated from the right ventricles of banded and sham-operated (control) animals by enzymatic dissociation. Ito was recorded by means of the whole cell patch clamp technique.

RESULTS

Heart weight:body weight ratio and cell membrane capacitance, as indications of hypertrophy, were increased by 17% (P < 0.05) and 32% (P < 0.01) respectively in the banded group. Analysis of Ito showed that in hypertrophied myocytes compared to normal controls: (1) the density of current was significantly reduced; (2) both the time to peak and the time constant of inactivation were increased; (3) the voltage-dependent steady-state availability was not changed, with similar potentials for half activation (30.4 +/- 6.8 mV in control and 33.9 +/- 8.5 mV in hypertrophied cells) and half inactivation (-12.3 +/- 3.3 mV in control and -11.4 +/- 2.7 mV in hypertrophied cells); (4) the time constant for recovery from inactivation was significantly increased regardless of the holding potentials (-50 mV, -70 mV or -90 mV).

CONCLUSIONS

Alterations of the transient outward potassium current with respect to its density, kinetics and recovery from inactivation can explain the prolongation of the action potential in myocytes isolated from pressure-overload hypertrophied heart and may thus be an important step in such cardiac adaptation.

Authors+Show Affiliations

Laboratory of General Physiology, URA CNRS 1869, University of Poitiers, France.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

7585836

Citation

Potreau, D, et al. "Depressed Transient Outward Current in Single Hypertrophied Cardiomyocytes Isolated From the Right Ventricle of Ferret Heart." Cardiovascular Research, vol. 30, no. 3, 1995, pp. 440-8.
Potreau D, Gomez JP, Fares N. Depressed transient outward current in single hypertrophied cardiomyocytes isolated from the right ventricle of ferret heart. Cardiovasc Res. 1995;30(3):440-8.
Potreau, D., Gomez, J. P., & Fares, N. (1995). Depressed transient outward current in single hypertrophied cardiomyocytes isolated from the right ventricle of ferret heart. Cardiovascular Research, 30(3), 440-8.
Potreau D, Gomez JP, Fares N. Depressed Transient Outward Current in Single Hypertrophied Cardiomyocytes Isolated From the Right Ventricle of Ferret Heart. Cardiovasc Res. 1995;30(3):440-8. PubMed PMID: 7585836.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Depressed transient outward current in single hypertrophied cardiomyocytes isolated from the right ventricle of ferret heart. AU - Potreau,D, AU - Gomez,J P, AU - Fares,N, PY - 1995/9/1/pubmed PY - 1995/9/1/medline PY - 1995/9/1/entrez SP - 440 EP - 8 JF - Cardiovascular research JO - Cardiovasc Res VL - 30 IS - 3 N2 - OBJECTIVE: The aim of this study was to investigate transient outward potassium current (Ito) changes as a basis for the prolongation of the action potential associated with cardiac hypertrophy. METHODS: Right ventricular hypertrophy was induced by chronic pulmonary artery constriction in adult male ferrets. After 4-6 weeks, hearts were excised and single myocytes were isolated from the right ventricles of banded and sham-operated (control) animals by enzymatic dissociation. Ito was recorded by means of the whole cell patch clamp technique. RESULTS: Heart weight:body weight ratio and cell membrane capacitance, as indications of hypertrophy, were increased by 17% (P < 0.05) and 32% (P < 0.01) respectively in the banded group. Analysis of Ito showed that in hypertrophied myocytes compared to normal controls: (1) the density of current was significantly reduced; (2) both the time to peak and the time constant of inactivation were increased; (3) the voltage-dependent steady-state availability was not changed, with similar potentials for half activation (30.4 +/- 6.8 mV in control and 33.9 +/- 8.5 mV in hypertrophied cells) and half inactivation (-12.3 +/- 3.3 mV in control and -11.4 +/- 2.7 mV in hypertrophied cells); (4) the time constant for recovery from inactivation was significantly increased regardless of the holding potentials (-50 mV, -70 mV or -90 mV). CONCLUSIONS: Alterations of the transient outward potassium current with respect to its density, kinetics and recovery from inactivation can explain the prolongation of the action potential in myocytes isolated from pressure-overload hypertrophied heart and may thus be an important step in such cardiac adaptation. SN - 0008-6363 UR - https://www.unboundmedicine.com/medline/citation/7585836/Depressed_transient_outward_current_in_single_hypertrophied_cardiomyocytes_isolated_from_the_right_ventricle_of_ferret_heart_ L2 - https://medlineplus.gov/potassium.html DB - PRIME DP - Unbound Medicine ER -