[Absence of effect of atropine on exocrine pancreatic secretion stimulated by cerulein]

The effect of atropine, 0.9, 1.8, 7 and 29 nmol/kg-1/h-1, on pancreatic exocrine secretion has been measured in seven dogs with gastric and pancreatic fistula in response to IV administration of increasing doses of cerulein (3.7 to 118 pmol/kg-1/h-1). Secretin was perfused continuously, at a rate of 20.5 pmol/kg-1/h-1, starting one hour before perfusion of cerulein. The administration of atropine, 7 and 29 nmol/kg-1/h-1, significantly (p less than 0.05) decreased the protein response to secretin. Only the injection of 29 nmol/kg-1/h-1 of atropine produced a significant decrease in the secretion of bicarbonate in response to secretin. The administration of 3.7 pmol./kg-1/h-1 and larger doses of cerulein significantly increased the secretion of bicarbonate and protein, compared to the levels obtained with the administration of secretin alone. None of the atropine doses showed a significant effect on the pancreatic response to the administration of cerulein. Only the highest dose of atropine, 29 nmol/kg-1/h-1, modified cardiac rate. These findings are consistent with the hypothesis that cholinergic innervation does not modify the effect of cerulein, a CCK analogue, on the pancreatic secretion of protein and bicarbonate in the dog.