The possible effect of nitric oxide on relaxation and noradrenaline release in the isolated rabbit urethra

Masaki Yoshida, Takaaki Akaike, Akito Inadome, Wataru Takahashi, Hiroshi Seshita, Makoto Yono, Shingo Goto, Hiroshi Maeda, Shoichi Ueda

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


We evaluated the effects of N(ω)-nitro-l-arginine (l-NNA, a nitric oxide (NO) synthase inhibitor) and carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (carboxy-PTIO, a NO scavenger) on NO-mediated relaxation and noradrenaline release from adrenergic nerve endings induced by electrical field stimulation in the rabbit urethra. Electrical field stimulation caused frequency-dependent relaxation of rabbit urethral smooth muscles precontracted with phenylephrine. The relaxation responses were significantly inhibited by treatment with l-NNA or carboxy-PTIO. The inhibitory effect of carboxy-PTIO was significantly weaker than that of l-NNA. Electrical field stimulation caused significant noradrenaline release from adrenergic nerve endings in the rabbit urethra. Treatment with carboxy PTIO enhanced electrical field stimulation-induced noradrenaline release, and simultaneous application of l-NNA and carboxy-PTIO did not further enhance noradrenaline release in the rabbit urethra. As carboxy-PTIO reacts only with the free radical NO, the present results suggest that free radical NO and NO-containing compounds are involved in the l-NNA-sensitive nitrergic nerve-mediated relaxation in the rabbit urethra. At the same time free radical NO has a prejunctional action by which it may inhibit noradrenaline release from adrenergic nerves. Copyright (C) 1998 Elsevier Science B.V.

Original languageEnglish
Pages (from-to)213-219
Number of pages7
JournalEuropean Journal of Pharmacology
Issue number2-3
Publication statusPublished - 1998 Sep 18
Externally publishedYes


  • Nitrergic nerve
  • Nitric oxide (NO)
  • Noradrenaline
  • Urethra

ASJC Scopus subject areas

  • Pharmacology


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