Decreased heart rate variability in transgenic mice overexpressing
atrial [beta]1-adrenoceptors.
Mansier, Pascale, Claire M[acute]edigue, Nathalie Charlotte,
Christophe Vermeiren, Edouard Coraboeuf, Edith Deroubai, Elisabeth
Ratner, Brigitte Chevalier, Jean Clairambault, Fran[cedilla]cois
Carr[acute]e, Thierry Dahkli, Brigitte Bertin, Pascale Briand, Donny
Strosberg, and Bernard Swynghedauw.
Unit[acute]e 127-INSERM and IFR Circulation-Lariboisi[grave]ere,
H[circumflex]opital Lariboisi[grave]ere, 41 bd de la Chapelle, 75010
Paris. France; NRIA Domaine de Voluceau. Rocquencourt, 75118 Le
Chesnay, France; Laboratoire de Physiologie Cellulaire,
Universit[acute]e Paris Sud, Orsay, France; Institute of Experimental
Cardiology, Laboratory of Experimental Endocrinology, Moscow, Russia;
Laboratoire de Physiologie M[acute]edicale. Facult[acute]e de
M[acute]edecine, 2 Avenue du Professeur L[acute]eon Bernard, 35042
Rennes, France; Laboratoire d'Immunopharmacologie Mol[acute]eculaire
and Laboratoire de G[acute]en[acute]etique et Pathologie
Exp[acute]erimentale. Institut Cochin de G[acute]en[acute]etique
Mol[acute]eculaire, 22 rue M[acute]echain, 75014 Paris, France
APStracts 3:0169H, 1996.
Heart Rate Variability, HRV, depends on various reflexes, including
the baroreflex or respiratory reflex. Experimental studies have
suggested that the sinoatrial node density in G protein-linked
receptors may be involved. Transgenic mice, T, with a specific 8 x
fold atrial overexpression of human [beta]1-AdrenoReceptor, [beta]1
-AR, have been generated in order to evaluate the role of the atrial
[beta]1-AR density on HRV. The heart rate was monitored using
telemetry and the signal was analysed using a quantitative time
-frequency domain analysis, the smoothed pseudo Wigner-Ville method,
and phase portrait maps. (i) Heart rate was unchanged, but the two
normal components of HRV were decreased in T. T have an unshortened
lifespan and no arrhythmias. (ii) Challenge of the animals by
propranolol showed no modulation of the HRV in T as compared to
controls. (iii) Isolated atrial strips from T had an increased basal
contractility and no isoproterenol-induced inotropic effect. (iv) The
basal level of cAMP production was lowered in T suggesting a shift in
adenylate cyclase isoforms.
Received 9 April 1996; accepted in final form 9 April 1996.
APS Manuscript Number H1212-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 May 96