Inhibitory action of galanin on gastric acid secretion in pentobarbital-anesthetized rats

The effects of galanin and two galanin fragments, GAL(9-29) and GAL(15-29), were studied for potential effects on pentagastrin- and bethanechol-stimulated gastric acid secretion in a pentobarbital-anesthetized rat experimental model. At a dose of 10 micrograms/kg/h, galanin potently inhibited pentagastrin-stimulated gastric acid secretion whereas inhibition of bethanechol-stimulated gastric acid secretion was not statistically significant. Simultaneous iv infusion of galanin and atropine did not affect the inhibitory action of the former. In similar experiments, a GAL(15-29) fragment was completely inactive whilst GAL(9-29) retained only about 5% potency. These results indicate that galanin probably induces its inhibitory effects by acting directly on the parietal cells rather than through a cholinergic pathway. They also demonstrate that the rat gastric acid inhibitory activity of galanin depends critically on the integrity of the first fourteen N-terminal amino acids.