Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Pelzmann, B; Schaffer, P; Bernhart, E; Lang, P; Mächler, H; Rigler, B; Koidl, B.
L-type calcium current in human ventricular myocytes at a physiological temperature from children with tetralogy of Fallot.
Cardiovasc Res. 1998; 38(2):424-432
Doi: 10.1016/S0008-6363(98)00002-9
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- Führende Autor*innen der Med Uni Graz
- Pelzmann Brigitte
- Co-Autor*innen der Med Uni Graz
- Bernhart Eva Maria
- Koidl Bernd
- Lang Petra
- Mächler Heinrich
- Rigler Bruno
- Schaffer Peter
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- Abstract:
- Objective: The aim was to investigate the electrophysiological properties of the L-type calcium current (I-Ca,I-L) in ventricular myocytes at a physiological temperature (36-37 degrees C) isolated fl sm children undergoing surgical repair of tetralogy of Fallot, Methods: I-Ca,I-L, was recorded with the patch-clamp technique in the single electrode whole-cell mode at a physiological calcium concentration(1.8 mmol/l) at 36-37 degrees C. Results: Under these conditions, maximum current density averaged -5.80 +/- 0.45 pA/pF. I-Ca,I-L, showed a bell-shaped current-voltage relationship: the curl ent activated at - 37.7 +/- 1.36 mV. peaked at + 9.31 +/- 1.60 mV and reversed at + 57.7 +/- 2.17 mV (n = 17). At +10 mV. time to peak of I-Ca,I-L, was 5.23 +/- 0.46 ms. membrane potentials for half-maximal steady-state activation and inactivation of I-Ca,I-L were - 6.02 and - 20.4 mV, respectively, the slope factors were 7. 16 mV for steady-state activation and 6,49 mV for steady-state inactivation. I-Ca,I-L, did not completely inactivate and showed a big window current between:cen -45 and + 40 mV. The inactivation of I-Ca,I-L showed a biexponential time course with a fast time constant ranging from 9.11 to 12.9 ms and a slow time constant ranging from 60.9 to 220 ms between - 30 and + 30 mV. Only the slow time constant showed a pronounced voltage dependency. The recovery from inactivation of I-Ca,I-L was biphasic with a fast time constant of 60.7 ms and a slow time constant of 619 ms. beta-Adrenergic stimulation with isoprenaline (1 mu mol/l) increased the I-Ca,I-L density from - 5.71 +/- 1.55 to - 13.8 +/- 1.96 pA/pF (142%; P < 0.05) at + 10 mV. Conclusions: The present study demonstrates that most of the electrophysiological properties of I-Ca,I-L in ventricular myocytes isolated from children with tetralogy of Fallot resemble those of adult ventricular cells. The existence of a big calcium window current could be involved in the occurrence of early afterdepolarizations which could lead to the high incidence of arrhythmias after. surgical repair of tetralogy of Fallot. (C) 1998 Elsevier Science B.V. AII lights reserved.
- Find related publications in this database (using NLM MeSH Indexing)
- Adrenergic beta-Agonists - pharmacology
- Biological Transport, Active - drug effects
- Calcium - metabolism
- Child, Preschool -
- Heart Ventricles -
- Humans -
- Ion Transport - drug effects
- Isoproterenol - pharmacology
- Membrane Potentials - drug effects
- Myocardium - metabolism
- Patch-Clamp Techniques -
- Tetralogy of Fallot - metabolism
- Find related publications in this database (Keywords)
- Human
- Ventricular Myocyte
- Calcium Current
- Isoprenaline
- Whole Cell Clamp
- Tetralogy of Fallot
- Hypertrophy