Atrial natriuretic peptide and sodium homeostasis in compensated
heart failure.
Lohmeier, Thomas E., H. Leland Mizelle, Glenn A. Reinhart, Jean-Pierre
Montani, C. Edward Hord, Jr., and Ralph H. Didlake.
University of Mississippi Medical Center, Department of Physiology
and Biophysics and Department of Surgery, 2500 North State Street,
Jackson, Mississippi 39216-4505
APStracts 3:0223R, 1996.
The purpose of this study was to determine whether high plasma levels
of atrial natriuretic peptide (ANP) in compensated heart failure are
important in the maintenance of sodium balance. This was achieved by
subjecting 8 dogs to bilateral atrial appendectomy (APX) to blunt the
ANP-response to pacing-induced heart failure. Five intact dogs served
as controls. In controls, 14 days of left ventricular pacing at 240
bpm produced a sustained fall in cardiac output and mean arterial
pressure of 40 and 20%, respectively; compared to cardiac output,
reductions in renal blood flow (up to 25%) were less pronounced and
even smaller decrements in GFR occurred (up to 9%). In spite of these
changes and a 3-fold elevation in plasma norepinephrine
concentration, plasma renin activity (PRA) did not increase and
sodium balance was achieved during the second week of pacing in
association with a 6-8 fold rise in plasma levels of ANP. Similar
responses occurred in 4 dogs in which APX was relatively ineffective
in blunting the ANP response to pacing. In marked contrast, there
were substantial increments in PRA and in plasma norepinephrine
concentration, and marked sodium and water retention during the last
week of pacing in 4 dogs with APX and severely deficient ANP. These
results indicate that ANP plays a critical role in promoting sodium
excretion in the early stages of cardiac dysfunction.
Received 28 February 1996; accepted in final form 31 May 1996.
APS Manuscript Number R118-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 28 June 96