AJP - Gastrointestinal and Liver Physiology, Vol 251, Issue 6 744-G751, Copyright © 1986 by American Physiological Society
The control mechanisms of gastric emptying are not overridden by motor stimulants
S. Wulschke, H. J. Ehrlein and C. Tsiamitas
We wanted to determine if an acceleration of the normal emptying rate by
motor stimulants interfers with control mechanisms limiting gastric
emptying. Therefore, we studied the effects of 5-hydroxytryptophane (5-HTP)
and cisapride on canine gastrointestinal motility and gastric emptying
after ingestion of viscous acaloric and nutritive meals. Prolonged
contractions and relaxations that change lumen size (isotonic component)
and wall tension (isometric component) are defined as "basal contractions"
and "basal relaxations", respectively. The nutrient meal emptied much
slower than the acaloric meal due to several alterations of gastric,
pyloric, and duodenal motility. Both drugs stimulated antral motility but
failed to accelerate gastric emptying of the nutrient meal. The main causes
for the failure were a basal relaxation of the proximal antrum and a basal
contraction of the duodenum. In conclusion, basal contractions of the
proximal antrum and duodenum play an important role in the process of
gastric emptying, and under physiological conditions the control mechanisms
of gastric emptying provide an optimal emptying rate that cannot be
markedly accelerated by 5-HTP and cisapride.
