EFFECT OF NEURAL BLOCKADES, GASTROINTESTINAL REGULATORY PEPTIDES, ANDDIVERSION OF GASTRODUODENAL CONTENTS ON PERIODIC PANCREATIC-SECRETIONIN THE PRERUMINANT CALF

The role of nerves, gastrointestinal peptides, and gastroduodenal cont ents in the regulation of pancreatic periodic function were studied in preruminant calves. Nine male, Friesian calves were surgically fitted with pancreatic and duodenal catheters, abomasal and duodenal cannula e, and duodenal electrodes. Pancreatic secretion oscillated in phase w ith the duodenal migrating myoelectric complex. Pancreatic secretion a nd duodenal motility were abolished by intravenous atropine (5 mu g . kg(-1). min(-1)). The frequency of pancreatic and duodenal cycles was similarly increased by motilin and decreased by pituitary adenylate cy clase activating polypeptide-27; secretin lengthened duodenal but not pancreatic cycles, resulting in loss of synchronization; cholecystokin in-8 and secretin increased pancreatic secretion (all infusions at 120 pmol . kg(-1). h(-1)); intraduodenal lidocaine (2%) or diversion of g astroduodenal contents reduced pancreatic secretion without altering p eriodicity. In conclusion, generation of pancreatic as well as of duod enal periodicity in the calf depends upon cholinergic neural efferent input. Secretin, cholecystokinin-8, pituitary adenylate cyclase activa ting polypeptide, duodenal contents, and mucosal afferent receptors se em to have relatively minor regulatory roles but can modulate the leve l of pancreatic secretion. The importance of enteric neural influence from the duodenum and the role of motilin in the regulation of pancrea tic periodicity and its synchronization with the duodenal motility cyc le remain to be determined.