Atrial natriuretic peptide regulates regional vascular volume and venous tone in humans.
OBJECTIVE
To date, the contribution of basal atrial natriuretic peptide (ANP) levels to resting vascular function in humans is unknown. In the present study we sought to investigate the role of ANP in regulating regional vascular volume and venous tone in healthy subjects.


RESULTS
We used radionuclide plethysmography to examine the effects of ANP and the ANP-receptor antagonist A71915 on forearm vascular volume. Creating pressure/volume relations, we determined changes in vascular volume, compliance, and tone. Performing dose-ranging studies, we additionally assessed the potency and specificity of A71915 in the forearm resistance vasculature. Equilibrium blood pool scintigraphy was then used to assess the effects of systemic administration of A71915 on regional intestinal vascular volume. Infusion of ANP increased forearm vascular volume in a dose-dependent manner (maximum 20%; P<0.001), exerting a maximum venodilating effect at plasma levels similar to that seen in heart failure. A71915 increased venous tone, thereby decreasing vascular volume by 9.6+/-1.1%, P<0.001 (forearm), and 2.6+/-0.5%, P=0.01 (intestinal beds). At an infusion ratio of 50:1, A71915 almost completely abolished the effects of ANP on forearm blood flow.


CONCLUSIONS
ANP locally regulates regional vascular volume and tone without affecting compliance.
Schmitt
Matthias
M
University of Wales College of Medicine, Department of Cardiology, Wales Heart Research Institute, Heath Park, Cardiff CF14 4XN,UK. matthschmitt@doctors.org.uk
Broadley
Andrew J M
AJ
Nightingale
Angus K
AK
Payne
Nicola
N
Gunaruwan
Prasad
P
Taylor
Justin
J
Lee
Leong
L
Cockcroft
John
J
Struthers
Allan D
AD
Frenneaux
Michael P
MP
D000328:Adult; D000368:Aged; D009320:Atrial Natriuretic Factor / Q000097:blood / Q000494:pharmacology / Q000502:physiology*; D001810:Blood Volume / Q000187:drug effects / Q000502:physiology*; D003187:Compliance / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000494:pharmacology; D017461:Receptors, Atrial Natriuretic Factor / Q000037:antagonists & inhibitors; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D044005:Tetrahydroisoquinolines / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014680:Veins / Q000502:physiology
D010446:Peptide Fragments; D044005:Tetrahydroisoquinolines; C078792:A 71915; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor