Intrarenal haemodynamic and glomerular responses to inhibition of nitric oxide formation in rabbits.
1. The renal effects of inhibiting nitric oxide (NO) formation using N-nitro-L-arginine (NOLA, 20 mg kg-1) were examined using micropuncture techniques in pentobarbitone-anaesthetized rabbits. 2. Renal vascular resistance doubled from 2.7 +/- 0.5 to 5.0 +/- 1.1 mmHg ml-1 min-1 after NOLA (P < 0.01), with similar percentage increases in both pre- (149 +/- 38%, P < 0.01) and postglomerular (158 +/- 42%, P < 0.01) resistance. 3. Glomerular capillary pressure rose from 33 +/- 1 to 40 +/- 1 mmHg after NOLA (P < 0.01) but despite this, glomerular filtration rate (GFR) and single nephron glomerular filtration rate did not significantly change. 4. Blood pressure increased 18 +/- 1 mmHg (P < 0.001) within 10 min of NOLA administration and remained near this level for the next 90 min. 5. The glomerular ultrafiltration coefficient (Kf) decreased significantly from 0.085 +/- 0.022 to 0.035 +/- 0.006 nl s-1 mmHg-1 (P < 0.05). 6. Urine flow and sodium excretion increased markedly (26 +/- 9 to 337 +/- 102 microliters min-1 and 5 +/- 2 to 342 +/- 12 mumol min-1 respectively, (P < 0.001)) and sodium fractional excretion rose from 1.0 +/- 0.3 to 8.0 +/- 2.2% (P < 0.01). 7. Thus, administration of NOLA to rabbits caused vasoconstriction of both pre- and postglomerular vessels, diuresis and natriuresis without significant change in GFR, and a reduction in Kf. The results suggest that NO may play an important role in the regulation of renal haemodynamics and glomerular function.
Denton
K M
KM
Baker Medical Research Institute, Prahran, Victoria, Australia.
Anderson
W P
WP
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D004231:Diuresis / Q000187:drug effects; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D007678:Kidney Glomerulus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009318:Natriuresis / Q000187:drug effects; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000502:physiology*; D019335:Nitroarginine; D011817:Rabbits; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology*; D014655:Vascular Resistance / Q000187:drug effects
D019335:Nitroarginine; D009569:Nitric Oxide; D001120:Arginine