Effects of pentagastrin, histamine, carbamylcholine and catecholamines on gastric secretion, motility and emptying in the rat.

We developed a simplified method for the simultaneous measurement of gastric secretion and gastric motility in the rat. By using this method, we investigated the actions of pentagastrin, histamine, carbamylcholine and catecholamines on the stomach. Carbamylcholine stimulated acid secretion and induced contraction of the stomach, but norepinephrine tended to inhibit acid secretion and induced relaxation of the stomach. Histamine induced relaxation first and then contraction after 2-5 min. Pentagastrin induced a relaxation that did not show dose dependence, but tachyphylaxis. Isoproterenol, which stimulated acid secretion in our experiments, induced relaxation of the stomach in a dose-dependent manner. We also investigated the relationship between gastric motility and gastric emptying. Carbamylcholine caused an enhancement of gastric emptying, but isoproterenol caused its suppression. Pentagastrin, histamine and norepinephrine did not affect gastric emptying. As shown in the results of our experiments, carbamylcholine caused stimulation of acid secretion, contraction of the stomach, and enhancement of gastric emptying. However, other secretagogues did not always induce contraction of the stomach or increase gastric emptying.