Effects of recombinant human hemoglobin on opossum sphincter of Oddi motor function in vivo and in vitro

Joseph J. Cullen, Jeffrey L. Conklin, Joseph Murray, Amber Ledlow, Gary Rosenthal

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Nitric oxide (NO) acts as a nonadrenergic, noncholinergic inhibitor neurotransmitter that regulates sphincter of Oddi (SO) motor function. Hemoglobin blocks NO activity by binding it after it is synthesized. We hypothesized that recombinant human hemoglobin (rHb1.1) affects SO motor function by scavenging NO. Under anesthesia, 12 opossums underwent biliary tract manometry. Following a stabilization period, six animals were given rHb1.1 (0.28 g/kg over 30 min), while six received bovine albumin (0.28 g/kg over 30 min). Recordings were made during the infusion and for 3 hr after the infusion. In an in vitro preparation, force transducers were used to record spontaneous contractions at two sites along the sphincter segment. After a control period, rHb1.1 (0.1 mM) or cyanomethemoglobin (0.1 mM) was added to the tissue bath and recordings continued for another 2 hr. Recombinant human hemoglobin decreased the frequency of contractions, increased resting tone, and blocked the relaxation phase of contraction in vivo. It increased the baseline amplitude, the frequency, and the peak amplitudes of contractions in vitro. Albumin or cyanomethemoglobin, which are unable to bind NO, had little effect on SO motor activity. We conclude that rHb1.1 may alter SO motor function by binding endogenous NO.

Original languageEnglish (US)
Pages (from-to)289-294
Number of pages6
JournalDigestive diseases and sciences
Volume41
Issue number2
DOIs
StatePublished - Mar 19 1996

Keywords

  • Hemoglobin
  • Sphincter of Oddi motility

ASJC Scopus subject areas

  • Physiology
  • Gastroenterology

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