Cholinergic dependence of pancreatic response to cholecystokinin in rats and guinea pigs

1. Lorglumide and atropine were used to examine the role of cholinergic mechanisms in the pancreatic secretory response to cholecystokinin in two animal species. 2. Anaesthetized rats and guinea pigs with jugular vein and pancreatic cannulae were used and the bile juice was recirculated. In the rat, the treatment with lorglumide (3 mumol/kg) as well as atropine (100 micrograms/kg) did not have effects on basal interdigestive secretion, whereas in guinea pigs only atropine decreased the protein output (41%) and the juice flow (47%) of the basal pancreatic secretion. 3. Infusion of cholecystokinin (150 pmol/kg/hr in the rat and 50 pmol/kg/hr in the guinea pig) induced a marked increase in pancreatic juice flow and protein output compared to saline controls. Pretreatment of both rat and guinea pig with lorglumide resulted in a marked attenuation of the cholecystokinin-evoked secretory response. 4. In the rats, atropine decreased the response to infusion of cholecystokinin octapeptide while this antimuscarinic agent had no effect in the response to cholecystokinin in the guinea pigs. 5. This study supports the concept that the influence of cholinergic system in pancreatic response to cholecystokinin shows interspecific differences.