We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Outwards currents in embryonic stem cell-derived cardiomyocytes.
- Authors
Gryshchenko, O.; Lu, Z.J.; Fleischmann, B.K.; Hescheler, J.
- Abstract
The aim of the present study was to investigate the expression and functional role of outwards currents during the early stages of cardiomyogenesis. The predominant repolarizing current in early-stage, embryonic stem (ES) cell-derived cardiomyocytes was a 4-aminopyridine (4-AP) sensitive [concentration for half-maximal inhibition (IC50) 1.7 mM], transient outward current (Ito) with a current density of 10.3±2.1 pA/pF (n=72). We observed two additional, rapidly activating, outwardly rectifying current components, IK,sus and Ires, in early- and late-stage cardiomyocytes. These currents were characterized by slow and no inactivation, respectively, during the depolarizing voltage step. IK,sus was detected in about 25% of cells investigated and displayed 4-AP hypersensitivity (IC50 29 µM), whereas Ires was found in all cells of both differentiation stages and was 4-AP insensitive. In contrast to early-stage cells, Ires formed the larger portion of the aggregate, whole-cell current in late-stage, ES cell-derived cardiomyocytes. The current densities of all three current components increased during development, however, the most prominent increase was observed for Ires from 3.6±0.8 pA/pF (n=72) to 8±1.1 pA/pF (n=35). In current-clamp recordings in early-stage, spontaneously contracting cardiomyocytes, 4-AP depolarized the cells, lengthened the action potential duration (APD) and increased the action potential frequency. In late-stage cells 4-AP had no effect on action potential frequency. We conclude that in early-stage cardiomyocytes Ito plays an important role in controlling electrical activity.
- Subjects
EMBRYONIC stem cells; HEART cells; STEM cells; HEART cytology; CARDIAC research; RESEARCH
- Publication
Pflügers Archiv: European Journal of Physiology, 2000, Vol 439, Issue 6, p798
- ISSN
0031-6768
- Publication type
Article
- DOI
10.1007/s004240051007