AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 6 794-G799, Copyright © 1986 by American Physiological Society
Blood flow limitation of stimulated gastric acid secretion in the rat
F. W. Leung, G. L. Kauffman Jr, J. Washington, O. U. Scremin and P. H. Guth
Secretagogue-stimulated gastric acid output is reduced when gastric mucosal
blood flow is below normal. We tested the hypothesis that the reduction in
acid secretion associated with reduced mucosal blood flow was due to a
decrease in the delivery of the secretagogue. Gastric acid output was
determined by continuous gastric lavage with 0.15 M NaCl, and gastric
corpus mucosal blood flow was measured by hydrogen gas clearance in
anesthetized, pylorus-ligated rats before and during a period of
hypovolemia-induced reduction in mucosal blood flow. A linear correlation
between pentagastrin- and histamine-stimulated gastric acid output and
gastric corpus mucosal blood flow during hypotension over a range of
mucosal blood flow rates was found, and each was expressed as a percentage
of the plateau values before hemorrhage. When the dose of pentagastrin was
doubled or tripled, or when the stimulation of gastric acid secretion was
vagus nerve stimulation, a stimulant of acid secretion that is independent
of blood flow for secretatogue delivery, the reduction in gastric acid
output by hypotension was not reversed. We conclude that stimulated gastric
acid secretion during hemorrhagic hypotension is blood flow-limited and not
related to inadequate delivery of secretagogue to parietal cells.
