Atrial natriuretic peptide influence on nitric oxide system in kidney and heart.
Atrial natriuretic peptide (ANP) and nitric oxide (NO) induce diuresis, natriuresis and diminish vascular tone. Our previous studies showed NO system is involved in ANP hypotensive effect. The aim was to investigate ANP effects on renal and cardiac NO-synthase (NOS) activity. Rats were divided into two groups: group I, infused with saline (1 h, 0.05 ml/min); group II, received ANP bolus (5 microg/kg)+ANP infusion (1 h, 0.2 microg/kg x min). NADPH-diaphorase activity (NADPH-d) was determined in kidney and heart. NOS catalytic activity was determined in renal medulla and cortex and cardiac atria and ventricle by measuring the conversion of l-[U(14)C]-arginine to l-[U(14)C]-citrulline. In group I, NOS activity was determined in basal conditions and plus 1 microM ANP and in group II, NOS activity was determined in basal conditions. NADPH-d was higher in group II than in group I in glomeruli, proximal tubule, cortical and medullar collecting duct, right atria and left ventricle. NOS activity was increased by in vitro ANP addition and, in vivo, ANP infusion in all the studied tissues. ANP treatment increases renal and cardiac NO synthesis. This effect would be independent on the hemodynamic changes induced by ANP. The activation of NO pathway would be one of the mechanisms involved in diuretic, natriuretic and hypotensive effects of ANP.
Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, IQUIMEFA-CONICET, Junín 956, Piso 7, 1113 Capital Federal, Argentina. mcosta@ffyb.uba.ar
María
M
de los Angeles Costa
Rosana
R
Elesgaray
Analía
A
Loria
Ana María
AM
Balaszczuk
Cristina
C
Arranz
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology / Q000502:physiology*; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D006325:Heart Atria / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D006352:Heart Ventricles / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D006651:Histocytochemistry; D007668:Kidney / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D007672:Kidney Cortex / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D007679:Kidney Medulla / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism; D009252:NADPH Dehydrogenase / Q000032:analysis / Q000378:metabolism; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009399:Nephrons / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D009569:Nitric Oxide; D009320:Atrial Natriuretic Factor; D019001:Nitric Oxide Synthase; D009252:NADPH Dehydrogenase; D019331:NG-Nitroarginine Methyl Ester