Role of cholecystokinin in the intestinal phase of pancreatic circulation in dogs

Abstract

The regulatory mechanisms of postprandial pancreatic hyperemia are not well characterized. The aim of this study is to clarify the role of cholecystokinin (CCK) in the intestinal phase of pancreatic circulation. Pancreatic, gastric, and intestinal blood flows were measured by ultrasound transit-time blood flowmeters in five conscious dogs. Pancreatic and gastric secretion and blood pressure were also monitored. Synthetic CCK octapeptide (CCK-8) or gastrin heptadecapeptide (gastrin-17) was infused intravenously, and milk was infused into the duodenum with or without loxiglumide, a specific CCK-A receptor antagonist. CCK-8 induced dose-related increases of pancreatic, but not gastric or intestinal, blood flow and protein secretion without affecting systemic blood pressure. Gastrin-17 did not affect pancreatic blood flow. An intraduodenal infusion of milk increased pancreatic and intestinal blood flows and pancreatic protein secretion. Loxiglumide completely inhibited pancreatic blood flow and protein responses to CCK-8 and milk but not the intestinal blood flow response. CCK is a potent and specific pancreatic vasodilator, with its effect mediated by CCK-A receptors. CCK plays an important role in the regulation of the intestinal phase of the pancreatic circulation in dogs.

Cholecystokinin as a regulator of cardiac function and postprandial gastrointestinal blood flow in rainbow trout (Oncorhynchus mykiss)

“…The observed, CCK-stimulated increase in gastrointestinal blood flow, is in concordance with mammalian studies, in which CCK have either direct (15,27) or indirect neurogenic effects [ (7,43); reviewed by Ruiz-Gayo et al (42)] on the gastrointestinal vessels. The effect of CCK can also be secondary to increases in, for example, pancreatic secretions and thus pancreatic blood flow, leading to overall increase in gastrointestinal blood flow (38).…”

“…The physiological significance of the difference in length and amino acid composition in position 6 is unknown; the different forms are, nevertheless, expressed differently in different parts of the trout (29). CCK is involved in the secretion of pancreatic juices in dogs (38), stimulating gallbladder contractions (1,2), as well as regulating gastric emptying in rainbow trout (39) and controlling functions of the central nervous system, such as satiety in rats (12).…”

“…This effect could be mediated through a neurogenic release of NO with CCK acting peripherally (43), although some suggest this effect is indirect via an increase in, for example, the pancreatic secretion and thus a local vasodilation in this tissue (38), and still others suggest that it is only vasoactive in high doses (41), doses that nevertheless could occur at discrete locations within the intestinal wall.…”