Influence of topical anesthetic, anticholinergic and ganglionic blocking agents on endogenous secretin release and pancreatic secretion in dogs.

The role of parasympathetic including local nerve control on the release of endogenous secretin and pancreatic secretion was studied in four conscious dogs prepared with both Thomas duodenal and gastric fistulae. Plasma secretin levels and pancreatic response during intraduodenal infusion of hydrochloric acid (HCl, graded doses doubling every 30 minutes from 0.3 to 2.4 mEq/10 min) rose significantly in dose-related fashion. Either atropine or hexamethonium, when given intramuscularly, did not inhibit HCl-stimulated endogenous release of secretin, but significantly suppressed pancreatic water, bicarbonate and protein secretions. Oxethazaine, when infused with HCl, suppressed a rise in both plasma secretin concentration and pancreatic secretion. The results obtained led to the conclusion that endogenous release of secretin is not under parasympathetic nervous control, but stimulated directly by intestinal contents.