Pulmonary vasorelaxant activity of atrial natriuretic peptide and brain natriuretic peptide in humans.
BACKGROUND
Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) exhibit in vitro pulmonary vasodilator activity, but little information is available regarding their effects in the human pulmonary vasculature. Their effects in the human pulmonary circulation and their ability to modulate the pulmonary pressor effects of angiotensin II have therefore been evaluated.


METHODS
Eight healthy volunteers were studied on three separate occasions. Infusions of either ANP, BNP, or placebo were given for 60 minutes with a concomitant infusion of angiotensin II given for the final 30 minutes. Pulmonary haemodynamics were measured by pulsed wave Doppler echocardiography at baseline (T0), before commencing angiotensin II (T30), and at the end of the infusion period (T60).


RESULTS
Mean pulmonary artery pressure (MPAP) showed a fall with ANP and BNP infusion at T30 compared with placebo. Although angiotensin II infusion had significant pulmonary pressor effects on all three study days, MPAP at T60 was lower when ANP (18.3 (2.0) mm Hg) and BNP (16.1 (1.5) mm Hg) were given concomitantly compared with placebo (21.8 (1.6) mm Hg).


CONCLUSIONS
These findings indicate that both ANP and BNP exhibit pulmonary vasorelaxant activity in humans in terms of antagonism of the pulmonary pressor effects of angiotensin II. This would support the hypothesis that ANP and BNP act as circulating counter-regulatory hormones in states of pathological pulmonary vasoconstriction.
Cargill
R I
RI
Department of Clinical Pharmacology, Ninewells Hospital and Medical School, University of Dundee, UK.
Lipworth
B J
BJ
D000328:Adult; D000804:Angiotensin II / Q000037:antagonists & inhibitors; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D020097:Natriuretic Peptide, Brain; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D011652:Pulmonary Circulation / Q000187:drug effects*; D014665:Vasodilator Agents
D009419:Nerve Tissue Proteins; D014665:Vasodilator Agents; D000804:Angiotensin II; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor