Effects of GABA on gastric acid secretion and ulcer formation in rats

The effects of gamma-aminobutyric acid (GABA), bicuculline and baclofen, orally and intraperitoneally (i.p.) administered, on the development of stress and pyloric ligation-induced gastric ulcers, were studied in rats. GABA, but not baclofen, significantly reduced the frequency and severity of both models as assessed by ulcer index, incidence and number of ulcers/animal. Gastric protection was dose-related in both experimental models and was completely antagonized by pretreatment with bicuculline methiodide, that blocks peripheral, but not central GABA receptors. All GABA effects were observed after oral and i.p. administration, but inhibition of gastric lesions was greater by the last route. Furthermore, GABA did not affect the acidity or the volume of gastric secretion in pylorus-ligated rats. Consequently its antiulcer activity appears to be mediated by factors unrelated to gastric acid secretion. Since the entry of GABA across blood-brain barrier is greatly restricted it may be concluded that stimulation of peripheral GABA receptors is primarily involved in its antiulcer action.