AJP - Heart and Circulatory Physiology, Vol 248, Issue 1 147-H150, Copyright © 1985 by American Physiological Society
Charged amphiphiles regulate heart contractility and sarcolemma-Ca2+ interactions
K. D. Philipson, G. A. Langer and T. L. Rich
We have used charged amphiphiles as phospholipid analogues to modulate the
interaction of Ca2+ with myocardial sarcolemma. The amphiphiles were
dodecyl sulfate, dodecyltrimethylamine, and lauryl acetate; these are
anionic, cationic, and neutral molecules, respectively. The hydrophobic
alkyl chain is identical in each case; only the hydrophilic head group is
varied. The anionic dodecyl sulfate (50-100 microM) augmented the Ca2+
binding and Na+-Ca2+ exchange activity of sarcolemmal vesicles by
approximately 80% and increases the contractility of rabbit papillary
muscle. Both developed force and its derivative were increased by
approximately 100% with no increase in rest tension. Cationic
dodecyltrimethylamine (20-100 microM) produced nearly opposite effects.
Neutral lauryl acetate (100 microM) had little apparent effect on any
measurement. The charged amphiphiles should be useful tools for further
elucidation of excitation-contraction coupling processes in a variety of
contractile tissues.
