AJP - Gastrointestinal and Liver Physiology, Vol 251, Issue 5 591-G596, Copyright © 1986 by American Physiological Society
Relation between duodenal alkaline secretion and motility in fasted and sham-fed dogs
S. J. Konturek and P. Thor
A relation between duodenal myoelectric and motor activity and alkaline
secretion has been investigated in conscious dogs under basal conditions
and following vagal excitation with and without pretreatment with atropine
or indomethacin. It was found that duodenal alkaline secretion shows
typical periodicity in phase with the myoelectric or motor activity of the
duodenum, reaching a peak during phase III and a nadir during phase I of
the migrating motor complex (MMC). Sham feeding interrupted the motor and
secretory MMC cycle and caused a prolonged increase in duodenal myoelectric
or motor activity as well as a sudden and marked rise in duodenal alkaline
secretion accompanied by a significant elevation in plasma gastrin and
pancreatic polypeptide. Atropine and indomethacin abolished the motor and
secretory duodenal cycles and reduced basal alkaline secretion
significantly. Atropine abolished, whereas indomethacin increased duodenal
myoelectric or motor activity during basal conditions and after vagal
stimulation. Neither atropine nor indomethacin abolished sham
feeding-induced duodenal alkaline secretion. We conclude that duodenal
alkaline secretion fluctuates cyclically in phase with duodenal motility,
vagal excitation results in a potent stimulation of duodenal motor and
secretory activity, and the mechanism of vagally induced duodenal alkaline
secretion is only partly cholinergic and does not involve endogenous
generation of prostaglandins.
