USE OF ANIMAL-MODELS IN PEPTIC-ULCER DISEASE

Considerable pr ogress has been made in the understanding of the forma tion of gastric erosions by the use of animals, The role of gastric ac id secretion in their pathogenesis has been clarified, Gastric erosion s are associated with the presence of acid in the stomach and slow gas tric contractions. With several different experimental procedures, the animal's body temperature falls; preventing the fall averts erosions. A fall in body temperature or exposure to cold are associated with th e secretion of thyrotropin-releasing hormone (TRH), and both increased and decreased concentration of corticotropin-releasing factor (CRH) i n discrete regions of rat brains, Thyrotropin-releasing hormone when i njected into specific sites in the brain produces gastric erosions and increases acid secretion and slow contractions, whereas CRH has the o pposite effects, One of the major sites of interaction of the two pept ides is in the dorsal motor complex of the vagus nerve, Thyrotropin-re leasing hormone increases serotonin (5-HT) secretion into the stomach. Serotonin counter-regulates acid secretion and slow contractions. Man y other peptides injected into discrete brain sites stimulate or inhib it gastric acid secretion.