Active bicarbonate-dependent secretion evoked by 5-hydroxytryptamine in porcine ileal mucosa is mediated by opioid-sensitive enteric neurons

Benedict T. Green, David R. Brown

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

5-Hydroxytryptamine (5-HT) mediates intestinal hypersecretion associated with infection and inflammation. We tested the hypothesis that 5-HT-induced anion secretion is mediated by an opioid-sensitive enteric neural circuit. 5-HT, at a contraluminal concentration of 10 μM, increased short-circuit current by 58±7 μA/cm2 in sheets of porcine ileal mucosa with attached inner submucosal plexus. Responses to 5-HT were inhibited by saxitoxin or indomethacin, and reduced in tissues bathed in Cl-- or HCO3--deficient media. 5-HT action was attenuated by saxitoxin in tissues bathed in Cl--free media, but not HCO3-free media. The δ-opioid receptor agonist [D-Pen2,5]enkephalin (0.1 μM) blunted the 5-HT change in short-circuit current by a mechanism sensitive to the δ-opioid receptor antagonist naltrindole. The inhibitory actions of [D-Pen2,5]enkephalin and saxitoxin were not additive. These results suggest that 5-HT stimulates HCO3--dependent ion transport through a mechanism involving prostanoids and an enteric neural pathway modulated by opioids.

Original languageEnglish (US)
Pages (from-to)185-190
Number of pages6
JournalEuropean Journal of Pharmacology
Volume451
Issue number2
DOIs
StatePublished - Sep 13 2002

Bibliographical note

Funding Information:
The authors thank Dr. Scott M. O'Grady (Department of Animal Science-Physiology, University of Minnesota) for expert technical advice during the execution of this project. This study was funded in part by NIH/NIDA grant R01 DA-10200. B.T.G. was a predoctoral trainee supported by ADAMHA/NIDA Psychoneuroimmunology and Substance Abuse training grant T32 DA07239.

Keywords

  • Bicarbonate-dependent secretion
  • Cannabinoid
  • Enkephalin
  • Inflammatory mediator
  • Prostanoid

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