title: Role of endothelium-derived nitric oxide in control of renal microvasculature in aging male rats.
abstract: 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.
authors.affiliation: Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson 39216-4505.
authors.forename: J F
authors.initials: JF
authors.lastname: Reckelhoff
authors.forename: R D
authors.initials: RD
authors.lastname: Manning
mesh_terms: 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
chemical_list: D019335:Nitroarginine; D009569:Nitric Oxide; D001120:Arginine