title: Neuronal nitric oxide synthase, nNOS, regulates renal hemodynamics in the postnatal developing piglet.
abstract: BACKGROUND
  Nitric oxide (NO) vasodilation critically modulates renal hemodynamics in the neonate compared with the adult. Based on the postnatal expression pattern of renal neuronal nitric oxide synthase (nNOS), the hypothesis was that nNOS is the major NOS isoform regulating renal hemodynamics in the immature, but not mature, kidney.
  
  
  RESULTS
  NOS inhibitors did not alter mean arterial pressure (MAP) in either group. Intrarenal S-methyl-L-thiocitrulline (L-SMTC) in newborns significantly reduced renal blood flow (RBF) 38 ± 4%, glomerular filtration rate (GFR) 42 ± 6%, and increased renal vascular resistance (RVR) 37 ± 7%, whereas intrarenal L-nitro-arginine methyl ester (L-NAME) affected RBF, GFR, and RVR equivalent to L-SMTC treatment. When L-NAME was administered after L-SMTC treatment, newborn renal hemodynamic changes were not further altered from what was observed when L-SMTC was administered alone. In contrast, in the adult, only intrarenal L-NAME, and not L-SMTC, affected renal hemodynamic responses.
  
  
  CONCLUSIONS
  In conclusion, these studies demonstrate that nNOS is an important regulator of renal hemodynamics in the newborn kidney, but not in the adult.
  
  
  METHODS
  Experiments compared renal hemodynamic responses with intrarenal infusion of L-NAME, an inhibitor of all NOS isoforms, with the selective nNOS inhibitor L-SMTC in the newborn piglet and the adult pig.
authors.affiliation: Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia, USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Rodebaugh
authors.forename: Miroslav
authors.initials: M
authors.lastname: Sekulic
authors.forename: William
authors.initials: W
authors.lastname: Davies
authors.forename: Stephanie
authors.initials: S
authors.lastname: Montgomery
authors.forename: Ali
authors.initials: A
authors.lastname: Khraibi
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Solhaug
authors.forename: Brian B
authors.initials: BB
authors.lastname: Ratliff
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001794:Blood Pressure; D002956:Citrulline / Q000008:administration & dosage / Q000031:analogs & derivatives; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D005919:Glomerular Filtration Rate; D006439:Hemodynamics / Q000187:drug effects; D007261:Infusions, Intra-Arterial; D007668:Kidney / Q000098:blood supply* / Q000187:drug effects / Q000201:enzymology*; D019331:NG-Nitroarginine Methyl Ester / Q000008:administration & dosage; D009569:Nitric Oxide / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012077:Renal Artery / Q000187:drug effects / Q000201:enzymology*; D012079:Renal Circulation / Q000187:drug effects; D013552:Swine; D013890:Thiourea / Q000008:administration & dosage / Q000031:analogs & derivatives; D014655:Vascular Resistance
chemical_list: D004791:Enzyme Inhibitors; D002956:Citrulline; D009569:Nitric Oxide; D052248:Nitric Oxide Synthase Type I; D013890:Thiourea; C086717:S-methylthiocitrulline; D019331:NG-Nitroarginine Methyl Ester