AJP - Regulatory, Integrative and Comparative Physiology, Vol 245, Issue 2 230-R240, Copyright © 1983 by American Physiological Society
Role of luminal acidity in the pathogenesis of stress-induced gastroduodenal disease
B. H. Natelson and W. N. Tapp
Infusion of progressively more acidic fluids into the stomachs of rats
stressed by immobilization had disparate effects on gastric erosive disease
despite their producing a stepwise fall in venous pH. At the highest
concentration infused, disease was exacerbated. However, at lower
concentrations, disease was ameliorated. The acidity of the infusate
altered the incidence but not the magnitude of the duodenal disease that
accompanies stress. When bicarbonate was given parenterally, systemic pH
was normalized but gastric disease still developed. Thus the level of
mucosal pH does not reliably predict whether or not gastric disease will
develop. When a series of progressively more basic fluids was infused into
the stomachs of stressed rats, gastric disease was lessened in only those
rats infused with the highest concentration of bicarbonate. Increasing the
pH of the infusate in a stepwise fashion produced a stepwise diminution of
duodenal disease incidence with no effect on duodenal disease severity.
When the stressed rat's mucosa was stimulated to secret acid by the
parenteral injection of secretagogues, gastric disease severity was the
same as in control animals given saline. Although secretagogue infusion did
not affect the incidence of stress-induced duodenal disease, it
significantly exacerbated the magnitude of the elicited disease. These
experiments suggest that luminal acid plays a negligible role in the onset
of stress-induced gastric disease but may be important in determining the
severity of the gastric disease once it has begun. Conversely the amount of
luminal acid correlates with the incidence of stress-induced duodenal
disease but does not seem to play a role in determining the severity of the
duodenal disease after it has begun.
