Influence of vagus on mechanisms for stimulation and inhibition of gastrin release.

In studies in dogs the gastrin response to food, to bombesin (1 micrgoram/kg-hr), and to somatostatin (2.5 and 5.0 microgram/kh-hr) plus food before and after truncal vagotomy was determined. Vagotomy caused an increase in basal levels of gastrin and in the release of gastrin after bombesin and food. Vagotomy augmented somatostatin suppression of food-stimulated gastrin release in a dose-dependent manner. We suggest that vagotomy causes a loss of both stimulatory and inhibitory vagal effects on gastrin release. Loss of vagal inhibition results in increased gastrin release to bombesin and food. Loss of vagal stimulation results in intensification of somatostatin-induced inhibition of postprandial gastrin release.