THE EFFECT OF ACUTE BILATERAL ADRENALECTOMY ON SEROTONIN-INDUCED INHIBITION OF GASTRIC-ACID SECRETION AND ACUTE GASTRIC-MUCOSAL INJURY IN RATS

Serotonin (5-hydroxytryptamine, 5-HT) produces many changes in gastric functional parameters, including the inhibition of gastric acid secre tion and changes in mucosal blood flow. Exogenous 5-HT has also been s hown to induce gastric erosion. The influence of adrenalectomy on expe rimental lesions in the rat gastric mucosa remains controversial. The aim of this study was to see the effects of adrenalectomy on pentagast rin stimulated gastric acid secretion in anaesthetized male Wistar rat s. Gastric acid was collected via cannulae placed in the stomach. 5-HT (3.5 mu mol/kg, i.v.) inhibited pentagastrin stimulated acid output b y 54% and produced haemorrhagic gastric lesions with a mean ulcer inde x of 2 +/- 0.3. Adrenalectomy prevented both 5-HT induced inhibition o f gastric acid secretion and mucosal injury. The results suggest that the effects of 5-HT require an intact adrenal gland.