The effect of peroxynitrite on sphincter of Oddi motility

Brian W. Herrmann, Joseph J. Cullen, Amber Ledlow, Joseph A. Murray, Jeffrey L. Conklin

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Background. Nitric oxide (NO*) is an inhibitory neurotransmitter that induces sphincter of Oddi relaxation. Superoxide (O2/(·-)-scavenging enzymes are present in enteric plexuses of the sphincter of Oddi and O2/(·- ) alters sphincter of Oddi motor function. O2/(·-) rapidly oxidizes nitric oxide (NO*) to form peroxynitrite (ONOO-), thus terminating the biological activity of NO*. The aim of our study was to determine the effects of ONOO- on sphincter of Oddi motility in vitro. Materials and methods. Adult opossums were sacrificed and the sphincter of Oddi was removed and placed in a tissue bath containing oxygenated Krebs solution at 37°C. In the first series of experiments, force transducers recorded tension in a transverse orientation at two sites along the spontaneously contracting sphincter of Oddi. In a second series of experiments, circular muscle strips were precontracted with carbachol and stimulated by an electrical field. Results. ONOO-, superoxide dismutase (SOD), Nω-nitro-L-arginine (L-NNA), or oxyhemoglobin were added to the tissue baths. ONOO- decreased the frequency of contractions in the spontaneously contracting sphincter of Oddi. Adding hemoglobin increased the frequency of contractions. ONOO- also increased the stimulation-induced relaxation compared to controls. The increase in relaxation induced by ONOO- was inhibited by oxyhemoglobin and L-NNA but not SOD. Pretreatment with oxyhemoglobin prevented the increase in the stimulation-induced relaxation caused by ONOO-. Conclusion. These results suggest that hemoglobin binds ONOO- or that ONOO- generates NO.

Original languageEnglish (US)
Pages (from-to)55-58
Number of pages4
JournalJournal of Surgical Research
Issue number1
StatePublished - Jan 1999


  • Motility
  • Peroxynitrite
  • Sphincter of Oddi

ASJC Scopus subject areas

  • Surgery


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