AJP - Gastrointestinal and Liver Physiology, Vol 249, Issue 6 725-G732, Copyright © 1985 by American Physiological Society
Emptying of saline meals by the cat stomach as a function of pyloric resistance
K. Schulze-Delrieu and C. K. Brown
The effect of the pylorus on the rate of gastric emptying and on the
pattern of flow from the stomach to the duodenum was studied. Cat stomachs
were filled with 50, 100, or 150 ml of 0.9 N saline, and intragastric
pressure and gastric fluid output were monitored continuously. The tip of
the collecting cannula was positioned either in the duodenum thus allowing
the pylorus to close) or in the pyloric segment thus preventing the pylorus
from interfering with gastric outflow). Initial experiments demonstrated
that fluid output was similar for the cat stomach in situ and in vitro.
Incremental output (i.e., the absolute volume emptied per collection
period) increased with the meal size and was proportional to the fluid
volume actually remaining in the stomach; fractional gastric output (i.e.,
the volume emptied as a percentage of the actual gastric volume) did not
change with meal size. The half time for gastric emptying was greater with
the collecting cannula positioned in the duodenum than in the pylorus
(e.g., with the 100-ml meal, 154 vs. 46 s). With the cannula in the
pylorus, gastric outflow was constant and ceased only when gastric emptying
had terminated. With the cannula in the duodenum, outflow was pulsatile and
ceased intermittently at gastric volumes that were subsequently emptied. We
conclude that the cat pylorus renders the outlet of the stomach continent
even to liquids; furthermore, the pylorus imparts a pulsatile pattern to
flow of liquids from the stomach to the duodenum.
