title: Milk and egg phospholipids act as protective surfactants against luminal acid in Necturus gastric mucosa.
abstract: BACKGROUND
  Our previous studies indicate that milk phospholipids have anti-ulcer properties in rats and humans, possibly by forming a hydrophobic surfactant layer at the epithelial surface. In the present study we measured intracellular pH and parameters of membrane resistances in gastric epithelium exposed to luminal acid using a microelectrode technique.
  
  
  METHODS
  Chambered isolated Necturus maculosus antral mucosa was exposed to pH 2.3, with or without 20-25 min pre-treatment with milk or egg phospholipids. The pH in surface epithelial cells was measured with double-barrelled liquid sensor pH/PD-microelectrodes.
  
  
  RESULTS
  Pre-treatment with phospholipids (2500-5000 micrograms P/mL) significantly (P < 0.01, n = 14) opposed intracellular acidification. Phospholipids significantly (P < 0.05, n = 14) increased the ratio of apical and basal membrane resistances, suggesting that they primarily affect the apical cell membrane. In contrast, there was no significant change in transmucosal resistance suggesting lack of effect on paracellular shunts in the 'leaky' epithelium.
  
  
  CONCLUSIONS
  Exogenous phospholipids of dietary origin may be used to form a protective layer in the gastric mucosa against irritants.
authors.affiliation: Department of Biomedical Sciences, University of Tampere, Helsinki, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Kivinen
authors.forename: S
authors.initials: S
authors.lastname: Tarpila
authors.forename: T
authors.initials: T
authors.lastname: Kiviluoto
authors.forename: H
authors.initials: H
authors.lastname: Mustonen
authors.forename: E
authors.initials: E
authors.lastname: Kivilaakso
mesh_terms: D000818:Animals; D004530:Egg Yolk / Q000737:chemistry*; D017097:Electric Impedance; D005753:Gastric Mucosa / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008892:Milk / Q000737:chemistry*; D009338:Necturus maculosus; D010743:Phospholipids / Q000302:isolation & purification / Q000494:pharmacology*; D013501:Surface-Active Agents / Q000494:pharmacology*
chemical_list: D010743:Phospholipids; D013501:Surface-Active Agents