Autonomic nervous control of gastric somatostatin and gastrin release

In anesthesized pigs the cut peripheral ends of splanchnic and vagal nerves were electrically stimulated in 5 min periods, and blood for somatostatin and gastrin determination collected from the right and left gastroepiploic veins and from the left femoral artery. The experimental animals were randomly allocated to two groups, one of which underwent acute bilateral adrenalectomy prior to the experiments. Gastroepiploic vein bloodflow increased in both groups during vagal as well as splanchnic stimulation. Mean systemic bloodpressures increased at least 70% during splanchnic stimulation. Prestimulatory somatostatin concentration was significantly higher in the left than in the right gastroepiploic vein. During vagal stimulation the somatostatin output from the gastric fundus decreased in both experimental groups, most pronounced though, in the adrenalectomized group. The somatostatin output from the antrum increased in the group with intact adrenals, and decreased in the adrenalectomized group (the difference is significant), thus indicating a role for circulating catecholamines in the regulation of somatostatin secretion. During splanchnic stimulation somatostatin output increased, but a marked fluctuation was observed in both groups. The arterial somatostatin concentration was unaffected of the nervous stimulation. In both groups gastrin concentration increased at least 10-fold with vagal stimulation, and significant changes from the prestimulatory level were not observed during splanchnic stimulation.