Inhibition of pancreatic exocrine secretion by galanin

The influence of extrapancreatic nerves on the inhibition of meal- and secretogogue-induced pancreatic secretion by galanin was studied in conscious dogs. Chronic pancreatic fistulae were created in five mongrel dogs and a second group of five dogs also underwent complete pancreatic denervation. After recovery, galanin dose response (150-1,200 pmol/kg/h) revealed that 600 pmol/kg/h was the lowest dose of galanin to significantly inhibit pancreatic exocrine secretion. Pancreatic responses to a mixed meal, cholecystokinin (CCK) dose response (12.5-200 ng/kg/h), and secretin dose response (16-500 ng/kg/h) were determined. The experiments were then replicated with a continuous background infusion of galanin (600 pmol/kg/h). Galanin inhibited meal-, CCK-, and secretin-induced bicarbonate outputs in both the innervated and denervated pancreas. Galanin also inhibited meal- and CCK-induced protein responses in both groups. We conclude that extrapancreatic nerves do not mediate the inhibitory effects of galanin.