Intra-arterial versus intravenous administration of gastric secretory inhibitors in conscious dogs. Effects of somatostatin, serotonin and isoprenaline on acid and pepsin secretion.

The purpose of the present study was to evaluate the effects of both intra-arterial and intravenous infusions of somatostatin, serotonin (5-hydroxytryptamine) and isoprenaline beta 1- + beta 2-adrenoceptor agonist) on gastric acid and pepsin secretion in conscious dogs with a gastric fistula. The drugs mentioned have been examined earlier for effects on gastric secretion in vivo during intravenous infusions and these effects could be hampered by the possible indirect mechanism of action as well as the different kinetics of metabolism. A catheter (vascular access port) allowed repeatedly gastric intra-arterial infusions. Somatostatin and serotonin possessed inhibitory effects on gastric acid and pepsin secretion and were without significant differences between the analyzed ways of administration. Intra-arterial infusion, isoprenaline possessed less potent inhibitory effects on gastric secretion: the effects were significant for pepsin secretion but were nonsignificant for acid secretion. The results suggest the mechanism of action of isoprenaline, somatostatin and sertonin to diverge, and for somatostatin and serotonin it was independent of the route of administration.