Implication of gastric mucosal histamine in inhibition by isoprenaline of pentagastrin-induced gastric secretion.

1 The effect of isoprenaline on pentagastrin-induced gastric secretion was studied in conscious rats with Heidenhain pouches. The influence of isoprenaline on pentagastrin-induced release and formation of gastric mucosal histamine was also examined.2 Isoprenaline strongly inhibited pentagastrin-induced acid secretion, an inhibition which could not be overcome by increasing the dose of pentagastrin.3 Propranolol blocked the inhibitory effect of isoprenaline on pentagastrin-induced acid secretion.4 Isoprenaline enhanced pepsin secretion induced by pentagastrin, an effect which was blocked by propranolol.5 Isoprenaline reduced the increase in formation and release of gastric mucosal histamine following pentagastrin infusion, an inhibitory influence which was almost completely blocked by propranolol.6 The inhibition by isoprenaline of pentagastrin-induced acid secretion is tentatively related to alterations in gastric mucosal histamine occurring simultaneously.