Downregulation of neutral endopeptidase (EC in the inflamed rat intestine

L. Hwang, R. Leichter, A. Okamoto, D. Payan, S. M. Collins, N. W. Bunnett

Research output: Contribution to journalArticlepeer-review


Intestinal inflammation induced by the nematode Trichinella spiralis is accompanied by increased intestinal concentrations of substance P, a mediator of inflammation and a stimulant of smooth muscle contraction, and by intestinal hypermotility. The expression of neutral endopeptidase (NEP), a cell surface enzyme that degrades substance P in the extracellular fluid, was examined in the inflamed intestine. NEP enzymatic activity, measured by a fluorometric assay, was reduced by 84-fold in jejunal mucosa-circular muscle and by 12-fold in jejunal longitudinal muscle-myenteric plexus within 6 days after infection with T. spiralis. The downregulation was unaffected by treatment with betamethasone and was still observed in athymic animals. NEP protein levels, examined by Western blotting, confirmed the loss of NEP from inflamed tissue. The specific activity for degradation of substance P was reduced by sixfold in jejunal mucosa-circular muscle and by twofold in jejunal longitudinal muscle-myenteric plexus of rats infected with T. spiralis compared with uninfected controls. Thus the downregulation of NEP resulted in reduced substance P degradation, which may contribute to functional abnormalities of the inflamed intestine.

Original languageEnglish (US)
Pages (from-to)G735-G743
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Issue number4 27-4
StatePublished - 1993


  • Trichinella spiralis
  • neuroimmunology
  • neuropeptide degradation
  • substance P

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)


Dive into the research topics of 'Downregulation of neutral endopeptidase (EC in the inflamed rat intestine'. Together they form a unique fingerprint.

Cite this