Determinants of renal vasoconstriction after systemic inhibition of nitric oxide synthesis in rats.
The effects of NG-nitro-L-arginine (L-NNA, 10 mg/kg i.v.) on renal hemodynamics were examined in control rats, rats in which renal perfusion pressure was prevented from rising after L-NNA by constricting the abdominal aorta, and rats in which tubuloglomerular feedback was inhibited by furosemide pretreatment, ureteral ligation, or both interventions combined. In control rats, L-NNA increased (P < 0.05) renal vascular resistance (274 +/- 27%) along with systemic arterial (54 +/- 4%) and renal perfusion (54 +/- 5%) pressures and decreased (P < 0.05) renal blood flow (57 +/- 4%). In rats in which renal perfusion pressure was prevented from increasing along with systemic arterial pressure (54 +/- 4%), the L-NNA-induced elevation of renal vascular resistance (173 +/- 27%) was less intense (P < 0.05). In another study, where renal perfusion pressure was fixed at pre-L-NNA levels, L-NNA-induced increases in renal vascular resistance (130 +/- 20%) were attenuated (P < 0.05) further with furosemide pretreatment (52 +/- 12%), with ureteral ligation (75 +/- 10%), and with furosemide pretreatment and ureteral ligation combined (32 +/- 8%). These data suggest that vasoconstrictor mechanisms linked to tubuloglomerular feedback and perfusion pressure elevation contribute to renal vasoconstriction after systemic inhibition of nitric oxide synthesis with L-NNA.
Brand-Schieber
E
E
Department of Pharmacology, New York Medical College, Valhalla 10595, USA.
Pucci
M
M
Nasjletti
A
A
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005246:Feedback / Q000187:drug effects; D005665:Furosemide / Q000494:pharmacology; D006439:Hemodynamics / Q000187:drug effects; D007678:Kidney Glomerulus / Q000187:drug effects / Q000502:physiology; D007684:Kidney Tubules / Q000187:drug effects / Q000502:physiology; D008026:Ligation; D008297:Male; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D019335:Nitroarginine; D051381:Rats; D017207:Rats, Sprague-Dawley; D012079:Renal Circulation / Q000187:drug effects*; D014513:Ureter; D014655:Vascular Resistance / Q000187:drug effects; D014661:Vasoconstriction
D004791:Enzyme Inhibitors; D019335:Nitroarginine; D005665:Furosemide; D001120:Arginine; D019001:Nitric Oxide Synthase