Further evidence of gastric back diffusion. Autoradiographic and mass spectrographic studies

In further studies of the phenomenon of back diffusion (acid, hydrogen (H+) ions), two different experimental approaches were used. 1. Autoradiographic studies with tritium-labelled water instilled in the stomach of fasted rats, revealed the activity to be overwhelmingly concentrated in the mucus layer. In contrast, following aspirin-induced gastric mucosal barrier disruption, radioactivity was prevalent in the mucosal membrane, diffusely scattered. 2. To answer the question as to whether tritium has moved in the gastric mucosa as an ion or as a water molecule, mass spectrographic studies were performed. Using the same experimental approach, comparison of tritium-labelled water with water containing another isotope (O18-water) demonstrated that after damage to the gastric mucosa, a change in the mass spectra of the gastric tissue occurred with tritium-labelled water, but not with O18-water. The results indicate that, indeed, it is not water molecules, but ionic particles represented by tritium that back diffuse, thus giving reason to believe that this mechanism also applies in the case of hydrogen ions.