Effect of Gastric, Extragastric and Truncal Vagotomy on the External Secretion of the Pancreas in the Dog

Abstract

Ten dogs were prepared with chronic total pancreatic fistulas. The effect of gastric, truncal and extragastric vagotomy on daily pancreatic secretion and response to secretin was investigated after truncal and gastric vagotomy. Daily volume of secretion fell 39% after selective vagotomy and a further 21% after truncal vagotomy in 6 of 9 dogs with no pancreatic infection or fibrosis. Extragastric vagotomy in 4 dogs reduced mean daily volume by 32%. The average basal secretion was decreased 33% after gastric vagotomy in eight dogs. Further reduction after truncal vagotomy was insignificant. In 9 dogs the response to secretion was slightly depressed after gastric vagotomy and significantly decreased after truncal vagotomy. Total output of amylase and protein decreased parallel to volume without change in concentration except after extragastric vagotomy when total output remained unchanged. Low daily output after gastric vagotomy as well as after truncal vagotomy alone could be explained on the basis of reduced gastric acid while reduction in daily output following extragastric vagotomy could not. Nor could the flattened secretion dose-response curve nor the greater depression of daily volume when truncal is superimposed on gastric vagotomy be explained on this basis. It seems from these experiments that selective vagotomy in the dog does not spare all vagal fibers to the pancreas nor does division of celiac and hepatic branches of the vagi interrupt all the fibers.