Action potentials in right and left ventricles from chronic hypoxic
rats: effect of almitrine.
Kreher, Paul, Christiane Keriel, and Xavier Leverve.
Laboratoire de Bio[umlaut]anerg[umlaut]atique, Universit[umlaut]a
Joseph Fourier, BP 53X, F-38041 Grenoble Cedex, France
APStracts 3:0262H, 1996.
Rats were exposed to a 3 week regimen of chronic normobaric hypoxia,
with or without almitrine treatment. Chronic hypoxia led to a
significant rise in the right ventricular mass, and lengthened the
action potential duration (APD) in right and in non-hypertrophied
left ventricle. Hypertrophy and APD lengthening were significantly
enhanced by almitrine. The classical acute hypoxia-induced shortening
in APD was much larger in hypoxia-adapted hearts. In these hearts,
almitrine treatment almost completely prevented such shortening,
while the acute hypoxia-induced decrease in cardiac contraction was
similar with or without almitrine. It is concluded that APD
lengthening during chronic hypoxia can occur independantly of
ventriclar hypertrophy. The similar directional effects of almitrine
and chronic hypoxia on APD support the hypothesis of an energy-linked
phenomenon. The dissociation of the almitrine effect on APD and
contractility is in accordance with the view of a cellular energy
compartmentation.
Received 7 June 1995; accepted in final form 9 May 1996.
APS Manuscript Number H520-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 4 July 96