Atrial, B-type, and C-type natriuretic peptides cause mesenteric vasoconstriction in conscious dogs.
Cardiovascular responses were compared with equimolar infusions of B-type (BNP) and C-type (CNP) with atrial natriuretic peptide (ANP) in conscious, instrumented dogs. On separate days, each natriuretic peptide or vehicle was infused (intravenously) at step-up doses of 2, 5, 10, and 20 pmol. kg-1. min-1 (20 min each dose) to increase circulating levels of the infused peptide from approximately 2- to 20-fold. Like ANP, infusions of BNP caused dose-related increases (P < 0.05) in mesenteric vascular resistance, urine flow, natriuresis, and hematocrit (changes at highest doses were 60 +/- 9, 334 +/- 113, 313 +/- 173, and 12 +/- 2%, respectively). BNP also lowered (P < 0. 05) plasma renin activity (-43 +/- 11%) and arterial pressure (-10 +/- 3%). Effects of BNP were independent of reflex sympathetic activation, since autonomic ganglion blockade did not attenuate the responses. CNP infusions had little effect except to increase (P < 0. 05) mesenteric vascular resistance (27 +/- 10%) and plasma ANP (41 +/- 7%). Cardiovascular actions of BNP, like those of ANP, counteract the renin-ANG system and may protect the heart by lowering cardiac preload (venous return) and afterload (arterial pressure) while maintaining blood flow to extrasplanchnic regions.
Woods
R L
RL
Howard Florey Institute, University of Melbourne, Parkville, Victoria 3052, Australia. R.WOODS@HFI.UNIMELB.EDU.AU
Jones
M J
MJ
D000818:Animals; D016275:Atrial Function; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001794:Blood Pressure / Q000502:physiology; D003243:Consciousness; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005730:Ganglionic Blockers / Q000494:pharmacology; D006400:Hematocrit; D007668:Kidney / Q000502:physiology; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000502:physiology; D020097:Natriuretic Peptide, Brain; D020098:Natriuretic Peptide, C-Type / Q000494:pharmacology*; D010425:Pentolinium Tartrate / Q000494:pharmacology; D012083:Renin / Q000097:blood; D014554:Urination / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects* / Q000502:physiology
D005730:Ganglionic Blockers; D020097:Natriuretic Peptide, Brain; D020098:Natriuretic Peptide, C-Type; D009320:Atrial Natriuretic Factor; D010425:Pentolinium Tartrate; D012083:Renin