Background: Morpho-functional studies of gastric mucosa are hampered by the lack of a technique allowing direct in situ visualization of the mucus in small living laboratory animals.
Methods: The material covering the gastric surface was studied in vivo in rats by magnetic resonance imaging (MRI) at 4.7 Tesla, and modification of its secretion was evaluated after pharmacological treatment.
Results: In unstimulated animals, the glandular portion of the stomach was lined by a layer of material emitting a signal of high intensity. Administration of 16,lfi-dirnethyl prostaglandin E, caused an accumulation of this material within a maximum 30 min after the administration of the drug. At 45 min, gastric emptying occurred and at 60 min, the lumen was almost free of material emitting a signal of high intensity. An increase in the intensity of the signal emitted from the material filling the gastric lumen was found after pentagastrin injection. After 45 min, the intensity of the signal emitted from the material in the gastric lumen decreased. 'H localized spectroscopy showed that after injection of pentagastrin there was an increase in the water proton peak within the gastric lumen. About one hour after stimulation, the water proton peak returned to the basal value.
Conclusions: This study demonstrates that MRI displays gastric mucus in living small rodents and represents a sensitive screening test for pharmacological action on this structure, enabling morpho-functional studies.