Autonomic nervous control of fundic secretion of somatostatin and antral secretion of gastrin and somatostatin in pigs.

By selective catheterization of gastric veins, we studied the secretion of gastrin and somatostatin from the antrum and of somatostatin from the gastric fundus-corpus region in anaesthetized pigs with or without acute adrenalectomy. The secretion was studied during electrical stimulation of the vagus nerves and the splanchnic nerves and simultaneous irrigation of gastric lumen with fluids of high, low, and neutral pH. The corpus-fundus somatostatin response to vagal stimulation was biphasic with a short-lasting initial increase followed by a lasting inhibition, which was little influenced by intraluminal pH or adrenalectomy. In pigs with intact adrenals, antral somatostatin secretion was increased by vagal stimulation, whereas in adrenalectomized pigs, the effect was inhibitory. The vagally induced inhibition was abolished when the intragastric pH was kept at pH 2. The antral gastrin secretion was strongly stimulated by vagal stimulation. The magnitude of the secretory response was inversely related to the pre-stimulatory somatostatin levels, but not to the nerve stimulation responses. Splanchnic stimulation increased arterial blood pressure and gastric blood flow, but had inconsistent effects on somatostatin and gastrin secretion.