Effects of antral vagotomy in dogs on gastrin and gastric secretion with various stimuli.

In four gastric-fistula dogs, selective antral vagotomy markedly reduced the vagal stimulation of gastrin release, thereby defining both the vagal pathway for stimulation of gastrin and the anatomic source of such gastrin release. Despite loss of gastrin response, vagal excitation by 100 mg/kg 2-deoxy-D-glucose (2-DG) produced the same acid and pepsin responses after antral vagotomy as before, but there was an approximately 40% diminished fundic response to pentagastrin, histamine, and synthetic human gastrin, as well as to endogenous gastrin released by graded doses of bombesin. Bethanechol did not reverse the defect, ruling out inadvertent fundic vagal denervation, nor did raising serum gastrin by bombesin alter the response to vagal stimulation by 2-DG. Fundic response to bethanechol was increased by approximately 60%, and the output of gastrin increased at least fivefold after antral vagotomy. Gastrin responses to food were diminished and those to sham feeding were eliminated. Separation of the denervated antral pouch had no additional effect on acid secretion. Vagal stimulation of gastric secretion thus occurs almost exclusively through direct cholinergic effects on the fundus with little or no contribution from antral gastrin. Vagal denervation sensitizes the antrum to cholinergic stimulation.