title: The effects of NG-nitro-L-arginine, a nitric oxide synthase inhibitor, on norepinephrine overflow and antidiuresis induced by stimulation of renal nerves in anesthetized dogs.
abstract: We examined the involvement of endogenous nitric oxide (NO) in noradrenergic neurotransmission and renal function in anesthetized dogs, by using NG-nitro-L-arginine (NOARG), a NO synthase inhibitor. Renal nerve stimulation (RNS) produced the frequency-dependent increase in the rate of norepinephrine secretion. The low frequency RNS (0.5-2.0 Hz) decreased urine flow and urinary excretion of sodium, without affecting renal hemodynamics. High frequency RNS (2.5-5.0 Hz) caused a more potent antidiuresis and renal vasoconstriction that resulted in reductions in renal blood flow and glomerular filtration rate. Intrarenal arterial infusion of NOARG, at a dose (10 micrograms/kg/min) which had no effect on renal hemodynamics, significantly enhanced the RNS-induced reductions of urine formation and renal vasoconstriction and increments in norepinephrine secretion rate. Qualitatively similar results were observed with a higher dose of NOARG (40 micrograms/kg/min), although this dose did decrease basal levels of renal blood flow and urine flow. Enhancement of NOARG on RNS-induced actions was abolished by the simultaneous administration of L-arginine. Endogenous NO probably has a role as inhibitory modulator of renal noradrenergic neurotransmission.
authors.affiliation: Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Egi
authors.forename: Y
authors.initials: Y
authors.lastname: Matsumura
authors.forename: S
authors.initials: S
authors.lastname: Murata
authors.forename: T
authors.initials: T
authors.lastname: Umekawa
authors.forename: K
authors.initials: K
authors.lastname: Hisaki
authors.forename: M
authors.initials: M
authors.lastname: Takaoka
authors.forename: S
authors.initials: S
authors.lastname: Morimoto
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004231:Diuresis / Q000187:drug effects*; D004285:Dogs; D004558:Electric Stimulation; D005260:Female; D007668:Kidney / Q000098:blood supply / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D008297:Male; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D019001:Nitric Oxide Synthase; D009638:Norepinephrine / Q000378:metabolism*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects; D019323:omega-N-Methylarginine
chemical_list: D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D009638:Norepinephrine