Milk and egg phospholipids act as protective surfactants against luminal acid in Necturus gastric mucosa.
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.
Kivinen
A
A
Department of Biomedical Sciences, University of Tampere, Helsinki, Finland.
Tarpila
S
S
Kiviluoto
T
T
Mustonen
H
H
Kivilaakso
E
E
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*
D010743:Phospholipids; D013501:Surface-Active Agents