IN-VIVO MORPHOFUNCTIONAL STUDY OF RAT GASTRIC MUCUS SECRETION

Background: Morpho-functional studies of gastric mucosa are hampered b y the lack of a technique allowing direct in situ visualization of the mucus in small living laboratory animals. Methods: The material cover ing the gastric surface was studied in vivo in rats by magnetic resona nce imaging (MRI) at 4.7 Tesla, and modification of its secretion was evaluated after pharmacological treatment. Results: In unstimulated an imals, the glandular portion of the stomach was lined by a layer of ma terial emitting a signal of high intensity. Administration of 16,16-di methyl prostaglandin E(2) caused an accumulation of this material with in a maximum 30 min after the administration of the drug. At 45 min, g astric emptying occurred and at 60 min, the lumen was almost free of m aterial emitting a signal of high intensity. An increase in the intens ity 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-1 localized spectroscopy showed that after injection of pentagastrin there was an increase in the water proton peak within the gastric lum en. About one hour after stimulation, the water proton peak returned t o the basal value. Conclusions: This study demonstrates that MRI displ ays gastric mucus in living small rodents anti represents a sensitive screening test for pharmacological action on this:structure, enabling morpho-functional studies. (C) 1995 Wiley-Liss, Inc.