Role of endothelium-derived nitric oxide in control of renal microvasculature in aging male rats.
The objective of this study was to evaluate the role of nitric oxide (NO) in the regulation of whole kidney and glomerular hemodynamics during aging. After 2 wk of oral treatment with N-nitro-L-arginine methyl ester (L-NAME; 4.5 mg.kg body wt-1.day-1) to inhibit NO synthesis, male rats, aged 3-5, 13-15, and 21-24 mo, were studied by micropuncture. Blood pressure increased by 50% in old (21-24 mo) rats with L-NAME but only 20-30% in the two younger groups. With L-NAME, renal vascular resistance increased fivefold in old rats but only twofold in younger groups. Glomerular capillary pressure increased 20-30% in younger L-NAME rats and 60% in older rats. Afferent and efferent resistances increased dramatically, and the glomerular capillary ultrafiltration coefficient decreased in all L-NAME-treated rats but most strikingly in the 21- to 24-mo-old group. Acute infusion of L-arginine significantly attenuated the effects of NO synthase inhibition on arterial pressure and renal hemodynamics in both young and old rats. This study confirms that NO synthesis blockade has a greater effect on renal hemodynamics in aging rats and implies that NO may play a progressively more important role in controlling renal function with advancing age.
Reckelhoff
J F
JF
Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson 39216-4505.
Manning
R D
RD
D000375:Aging / Q000502:physiology*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001160:Arterioles / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006400:Hematocrit; D007678:Kidney Glomerulus / Q000098:blood supply; D008297:Male; D008833:Microcirculation / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D009569:Nitric Oxide / Q000502:physiology*; D019335:Nitroarginine; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012039:Regional Blood Flow / Q000187:drug effects; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology*; D014655:Vascular Resistance / Q000187:drug effects
D019335:Nitroarginine; D009569:Nitric Oxide; D001120:Arginine