T. Onaga et al., PACAP STIMULATES PANCREATIC EXOCRINE SECRETION VIA THE VAGAL CHOLINERGIC NERVES IN SHEEP, Regulatory peptides, 72(2-3), 1997, pp. 147-153
The present study evaluates the possible role of the vagus nerves in m
ediating the stimulatory effect of PACAP-27, PACAP-38 and VIP on the e
xocrine pancreas, especially on enzyme secretion which is atropine sen
sitive in sheep. The animals were equipped with two cannulae into the
common bile duct, a duodenal cannula, and a ruminal cannula under anes
thesia. The bilateral cervical vagus nerves were coiled with a cooling
device. In conscious animals, the peptides were infused intravenously
for 10 min at 10 pmol kg(-1) min(-1) in phase II of the duodenal migr
ating motor complexes and the same peptide infusion was repeated in th
e reversible cooling blockade of the vagus nerves. Increment in fluid
secretion was not significantly altered by the vagal blockade in all t
he peptide infusions, while increment in bicarbonate ion by only PACAP
-27 was inhibited by the vagal blockade. Increments in protein and amy
lase output decreased significantly to 32.0+/-5.0 and 23.2+/-2.6% in P
ACAP27, and to 26.1+/-7.7 and 20.8+/-6.4% in PACAP-38 in the vagal blo
ckade, but the increments by VIP did not decrease. These results demon
strate that circulating PACAP stimulates pancreatic enzyme secretion v
ia the vagal cholinergic preganglionic neurons in sheep, suggesting th
e central action of PACAP. (C) 1997 Elsevier Science B.V.