A PHYSICAL IDENTITY FOR THE GASTRIC-MUCOSAL BARRIER

An oligolamellar lining which is probably phospholipid has been demonstrated on the gastric mucosal surface of the rat by transmission electron microscopy using fixation procedures specially developed to avoid the destruction of hydrophobic surfaces. This structure is unlikely to be an artefact since the use of two hydrophobic probes in epifluorescence microscopy gave emissions characteristic of oligolamellar phospholipid prepared in vitro. Moreover, lipid solvents almost eliminated both the fluorescence and the hydrophobicity. An oligolamellar lining was seen also on deeper structures, including oxyntic ducts and canaliculi in parietal cells, and it might offer a physical basis for the hitherto elusive gastric mucosal barrier. Parietal cells were also found to contain multilamellar bodies which, in the lung at least, represent phospholipid (surfactant) in a particularly surface-active form and one conducive to its deposition on tissue surfaces. This suggests that the parietal cell could gear the protection (surfactant) to the potential insult (acid) by secreting both together. The demonstration of a simple physical barrier preventing the stomach from digesting itself is discussed in regard to suggesting the use of certain surface-active foods which could be beneficial in preventing gastric ulcers and their recurrence after the acute phase has been treated using conventional therapies.