Natriuretic peptides maintain sodium homoeostasis during chronic volume loading post-myocardial infarction in sheep.
The impaired ability to excrete sodium is a key feature of established congestive heart failure and is also apparent in asymptomatic left ventricular (LV) impairment. However, few studies have examined responses to chronic volume loading immediately post-myocardial infarction (MI). Experimental MI was induced in six sheep by thrombogenic coil coronary artery occlusion, and resulted in significant LV dysfunction with reduced LV ejection fraction ( P =0.001) and subsequent remodelling (increased LV volumes, P =0.015). Chronic volume loading with 2, 3 and 4 litres/day intravenous saline (each for 7 days) showed no evidence of renal sodium or volume retention in sheep with experimental MI compared with six normal control sheep. Plasma levels of brain natriuretic peptide (BNP), N-terminal pro-BNP and cGMP (all P <0.05) were higher in the MI group compared with normal control sheep. There were no differences in haemodynamics, body mass or renin-aldosterone levels between groups. This study provides evidence that natriuretic peptides play a pivotal role in preserving volume/electrolyte balance in the early stages of post-MI cardiac dysfunction.
Charles
Christopher J
CJ
Christchurch Cardioendocrine Research Group, Christchurch School of Medicine and Health Sciences, PO Box 4345, Christchurch, New Zealand. chris.charles@chmeds.ac.nz
Elliott
John M
JM
Nicholls
M Gary
MG
Rademaker
Miriam T
MT
Richards
A Mark
AM
D000818:Animals; D002908:Chronic Disease; D006152:Cyclic GMP / Q000097:blood; D005260:Female; D006706:Homeostasis; D023421:Models, Animal; D009203:Myocardial Infarction / Q000378:metabolism*; D020097:Natriuretic Peptide, Brain / Q000097:blood / Q000378:metabolism*; D012756:Sheep; D012964:Sodium / Q000378:metabolism*; D012965:Sodium Chloride / Q000008:administration & dosage; D018487:Ventricular Dysfunction, Left
D020097:Natriuretic Peptide, Brain; D012965:Sodium Chloride; D012964:Sodium; D006152:Cyclic GMP