T. Onaga et al., EFFECT OF L364-718 ON INTERDIGESTIVE PANCREATIC EXOCRINE SECRETION AND GASTRODUODENAL MOTILITY IN CONSCIOUS SHEEP, Regulatory peptides, 68(2), 1997, pp. 139-146
The present study examined roles of endogenous cholecystokinin (CCK) a
nd CCK-A receptors in the regulation of pancreatic exocrine secretion
and gastroduodenal motility in conscious sheep during interdigestive p
eriod. Interdigestive exocrine secretion of ovine pancreas changed cyc
lically corresponding with cycle of duodenal migrating myoelectric com
plexes (MMC). During second phase of the duodenal MMC, intravenous inj
ection of L364 718 at 2.45 mu mol kg(-1) inhibited exogenous CCK-8-ind
uced pancreatic exocrine secretion. Intravenous infusion of the antago
nist at 2.45 mu mol kg(-1)/5 min for 5 min also inhibited significantl
y the pancreatic enzyme secretion without CCK-stimulation to half of t
hat in the control, but not the fluid and bicarbonate secretion. Atrop
ine infusion (i.v.) at 72.0 nmol kg(-1)/5 min significantly inhibited
not only enzyme but also fluid and bicarbonate secretion. Correspondin
g to the inhibition of the exocrine secretion, L364 718 induced premat
ure phase III in duodenal electromyogram (EMG) in three of the five sh
eep. Omasal EMG was inhibited slightly but significantly by L364 718,
however, neither regular ruminal contractions nor abomasal EMG were al
tered by L364 718. In contrast, the atropine infusion inhibited only a
mplitude of ruminal contractions. These results suggest that endogenou
s CCK contributes to the regulation of interdigestive pancreatic exocr
ine secretion, omasal contractions and duodenal MMC in the ovine gastr
ointestinal tract via CCK-A receptors. (C) 1997 Elsevier Science B.V.