The properties of sodium and potassium currents of cultured adult
human atrial myocytes.
Feng, Jianlin, Gui-Rong Li, Bernard Fermini, and Stanley Nattel.
Department of Medicine, Montreal Heart Institute (JF, GL, BF, SN),
Montreal HIT IC8, the University of Montreal (GL, BF, SN), Montreal
H3C 3J7, and the Department of Pharmacology and Therapeutics, McGill
University (SN) Montreal, H3G 1Y6
APStracts 2:0475H, 1995.
Cultured cell systems are valuable for the study of regulation of
phenotypic expression, but little is known about the
electrophysiologic properties of human cardiac tissues in culture.
The present studies were designed to determine the feasibility of
maintaining human atrial myocytes in primary culture, and to assess
changes in Na+ and K+ (Ito and IKur) currents. Within 24 h of
culture, cells assumed an ovoid shape which they maintained for up to
7 days. The voltage dependence, kinetics, and density of INa were
unchanged in culture. The activation properties of Ito (kinetics and
voltage dependence) were not altered, but Ito density (current
normalized to cell capacitance) was reduced and inactivation
properties were altered (negative shift in voltage dependence, slowed
kinetics) in cultured compared to fresh cells. The absolute current
amplitude, kinetics, voltage dependence and 4-aminopyridine
sensitivity of IKur were unchanged, but current density was
increased. All changes in ionic currents occurred within 24 h of
culture, and remained stable for the next 4 days. We conclude that
human atrial myocytes can be maintained in primary culture, that the
qualitative properties of INa, Ito, and IKur remain constant but that
some quantitative changes occur, and that cultured human atrial
myocytes may be valuable for studies of the molecular mechanisms and
regulation of cardiac ion channel function in man.
Received 14 July 1995; accepted in final form 29 September 1995.
APS Manuscript Number H657-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95