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Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
Published on: July 3, 2013
Adrenergic Modulation of Potassium Currents in Isolated Human Atrial Myocytes
M.-J. Su1, J.-F. Chi, S.-H. Chu
1Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC.
Abstract:
The adrenergic modulation of inwardly rectifying and depolarization-activated outward potassium currents was studied in single cardiac myocytes obtained from the human atrium. Membrane currents were recorded in enzymatically dissociated cells using the whole-cell voltage-clamp technique. It was observed that, in the presence or absence of atenolol (or 1 &mgr;M propranolol), 30 &mgr;M phenylephrine attenuated inwardly rectifying and depolarization-activated outward potassium currents including both transient and late-activated current. This suppressant effect of phenylephrine could be prevented by pretreatment with an alpha-adrenoceptor antagonist. Isoproterenol (30 &mgr;M) increased the late outward potassium current and net transient outward current. It is concluded that, in human atrial myocytes, alpha-adrenergic activation reduces depolarization-activated transient and late outward potassium current and inwardly rectifying background potassium current. beta-Adrenergic activation resulted in an increase in the depolarization-activated transient and late outward potassium current. Copyright 1994 S. Karger AG, Basel
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