The role of cholinergic nerve on plasma concentration of immunoreactive secretin and pancreatic bicarbonate secretion was investigated in conscious and anaesthetized dogs. 2. In conscious dogs with gastric and pancreatic fistulae, I.V. administration of 2-deoxy-D-glucose (2-DG) potentiated the pancreatic bicarbonate secretion stimulated by duodenal acidification. 3. In conscious dogs with same preparation, I.V. administration of atropine inhibited the pancreatic bicarbonate secretions stimulated by duodenal acidification or exogenous secretin. 4. Neither 2-DG nor atropine had any effect on endogenous release of secretin. 5. In anaesthetized dogs, pancreatic bicarbonate secretion stimulated by duodenal acidification was decreased by bilateral cervical vagotomy. However, plasma secretion concentration achieved by duodenal acidification was not different from that of pre-vagotomy state. 6. The data indicate that the changes of cholinergic tone do not affect release of endogenous secretin but alter the exocrine pancreatic bicarbonate secretion stimulated by secretin.
