Effect of atrial natriuretic peptide on muscle sympathetic activity and its reflex control in human heart failure.
BACKGROUND
The purpose of this study was to determine if atrial natriuretic peptide (ANP) exerts a relative inhibitory effect on muscle sympathetic nerve activity (MSNA) at rest and during nonhypotensive lower body negative pressure (LBNP) in heart failure, as in healthy subjects.


RESULTS
Fifteen men (age 39+/-2 years [mean+/-SE]) with dilated cardiomyopathy (ejection fraction 18+/-3%) received intravenous ANP (50 microgram bolus, then 50 ng. kg-1. min-1) and nitroglycerin (NTG, 8 mg/min) as a hemodynamic control. During each infusion MSNA, blood pressure (BP), central venous pressure (CVP), and heart rate (HR) were recorded before and during LBNP at -6 and -12 mm Hg. NTG and ANP caused similar and significant reductions in CVP and diastolic BP, but resting MSNA did not increase with either infusion. LBNP at -6 mm Hg lowered CVP (P<0.05), whereas LBNP at -12 mm Hg caused significant reductions in CVP, systolic BP, and diastolic BP. These effects of nonhypotensive and hypotensive LBNP on CVP and BP were similar during ANP and NTG infusions, yet MSNA was lower both before and with LBNP during ANP (P<0.02). Nonhypotensive LBNP increased MSNA during NTG (+133+/-68 Units; P<0.001) but not during ANP infusion (+24+/-23 Units; P=NS).


CONCLUSIONS
These observations are consistent with the concept that ANP exerts a sympathoinhibitory action in heart failure. This is most evident in response to reductions in atrial pressures that do not affect systemic BP.
Abramson
B L
BL
Divisions of Cardiology, the Toronto Hospital and Mount Sinai Hospital, and the Centre for Cardiovascular Research, University of Toronto.
Ando
S
S
Notarius
C F
CF
Rongen
G A
GA
Floras
J S
JS
D000328:Adult; D009320:Atrial Natriuretic Factor / Q000627:therapeutic use*; D002303:Cardiac Output, Low / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology*; D002311:Cardiomyopathy, Dilated / Q000150:complications; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008150:Lower Body Negative Pressure; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation*; D005996:Nitroglycerin / Q000627:therapeutic use; D012018:Reflex / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000503:physiopathology
D009320:Atrial Natriuretic Factor; D005996:Nitroglycerin