AJP - Gastrointestinal and Liver Physiology, Vol 256, Issue 2 390-G395, Copyright © 1989 by American Physiological Society
Omeprazole and cimetidine versus pentagastrin in canine ex vivo gastric chamber
K. R. Larsen, M. M. Ives, N. F. Jensen 3rd, E. Carlsson and H. Larsson
Department of Medicine, University of Utah, Salt Lake City 84132.
The effects of acid inhibitory doses of omeprazole were compared with
equieffective doses of cimetidine in the canine ex vivo stomach model (n =
30). Systemic blood pressure, temperature, stomach fluid and ion fluxes,
potential difference, blood flow rates, and arterial and venous blood gases
were monitored during each of nine 30-min periods. Two resting periods
preceded seven periods of pentagastrin stimulation. During the last four of
these, the drug effect was recorded (cimetidine 1.2 or 4.8 mumol.kg-1.h-1;
omeprazole 0.3, 0.6, or 1.2 mumol/kg). Omeprazole (1.2 mumol/kg) produced
100% inhibition of stimulated acid efflux, no significant decrease in total
gastric blood flow (venous outflow), 90% return of potential difference
(PD) toward resting values, and a 55% reduction in stimulated oxygen
consumption. Omeprazole also showed a dose-dependent K+ efflux at the two
lower doses. Cimetidine (4.8 mumol.kg-1.h-1) given during pentagastrin
stimulation showed a 70% decrease in total gastric blood flow, a 40% return
of PD toward resting, and a 77% reduction in stimulated oxygen consumption.
Neither drug showed significant changes in mucosal blood flow from resting
values, thus supporting the principle that changes in gastric acid
secretion and changes in blood flow are not necessarily correlated.
