title: Effect of reactive oxygen species and nitric oxide in the neural control of intrarenal haemodynamics in anaesthetized normotensive rats.
abstract: OBJECTIVE
  This study examined the interaction between reactive oxygen species and nitric oxide (NO) in mediating the decrease in renal blood flow (RBF) evoked by sympathetic renal nerve stimulation (RNS).
  
  
  METHODS
  Groups of male Wistar rats were subjected to RNS at different frequencies prior to, and following, an infusion of: (i) tempol, the superoxide dismutase (SOD) mimetic, (ii) tempol plus the hydrogen peroxide-degrading enzyme catalase (tem + cat), (iii) diethyldithiocarbamic acid (DETC), a SOD inhibitor, (iv) the nitric oxide synthase (NOS) inhibitor, L-nitro-arginine methyl ester (L-NAME) alone, or (v) L-NAME followed by tempol, into the kidney cortico-medullary border (CMB). Blood perfusion within the cortical (CBP) and medullary (MBP) regions of the kidney was measured using Laser-Doppler flowmetry.
  
  
  RESULTS
  Infusion of tempol CMB significantly attenuated RNS-evoked reductions in CBP (by 22% at 8 Hz; P < 0.05), but not MBP. When tempol and catalase were co-infused to reduce both ROS and hydrogen peroxide (H2 O2 ), respectively, there was a significantly greater attenuation of the RNS-evoked reduction in CBP compared with that of tempol alone. Infusion of either DETC or L-NAME alone did not significantly affect the CBP or MBP responses to RNS. Similarly, RNS following tempol infusion with L-NAME also had no effect on CBP and MBP over and above the group that received tempol alone.
  
  
  CONCLUSIONS
  These results suggest that reactive oxygen species such as superoxide and H2 O2 have a direct role in reducing renal vascular compliance in response to RNS, rather than indirectly through scavenging NO.
authors.affiliation: Department of Physiology, University College Cork, Cork, Ireland.
authors.forename: A F
authors.initials: AF
authors.lastname: Ahmeda
authors.forename: M G
authors.initials: MG
authors.lastname: Rae
authors.forename: E J
authors.initials: EJ
authors.lastname: Johns
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D003497:Cyclic N-Oxides / Q000494:pharmacology; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006439:Hemodynamics / Q000502:physiology*; D007668:Kidney / Q000098:blood supply* / Q000294:innervation / Q000378:metabolism; D017078:Laser-Doppler Flowmetry; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology*; D013113:Spin Labels; D013564:Sympathetic Nervous System
chemical_list: D000975:Antioxidants; D003497:Cyclic N-Oxides; D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D013113:Spin Labels; D009569:Nitric Oxide; C001803:tempol; D019331:NG-Nitroarginine Methyl Ester
keywords: nitric oxide; reactive oxygen species; renal blood pressure; renal nerve stimulation