Inhibition of nitric oxide synthesis blocks the inhibitory response to capsaicin in intestinal circular muscle preparations from different species

Rita Benko, Zsofia Lazar, Sarolta Undi, Laszlo Illenyi, Andras Antal, Örs Peter Horvath, Zoltan Rumbus, Matyas Wolf, Carlo A. Maggi, Lorand Bartho

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19 Citations (Scopus)


Moderate concentrations of the sensory stimulant drug capsaicin caused relaxation in human and animal intestinal circular muscle preparations (guinea-pig proximal, mouse distal colon, human small intestine and appendix) in vitro. With the exception of the guinea-pig colon, the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine (L-NOARG; 10-4 M) strongly inhibited the relaxant effect of capsaicin. Tetrodotoxin, an inhibitor of voltage-sensitive Na+ channels failed to significantly reduce the inhibitory effect of capsaicin in the guinea-pig colon, human ileum and appendix; it caused an approximately 50% reduction in the mouse colon. The relaxant effect of capsaicin was strongly reduced in colonic preparations from transient receptor potential vanilloid type (TRPV1) receptor knockout mice as compared to their wildtype controls. It is concluded that nitric oxide, possibly of sensory origin, is involved in the relaxant action of capsaicin in the circular muscle of the mouse and human intestine.

Original languageEnglish
Pages (from-to)2773-2782
Number of pages10
JournalLife Sciences
Issue number24
Publication statusPublished - Apr 29 2005



  • Appendix
  • Capsaicin
  • Colonic circular muscle (mouse, guinea-pig)
  • Ileum (human)
  • Nitric oxide
  • Tetrodotoxin

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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