AJP - Gastrointestinal and Liver Physiology, Vol 248, Issue 4 437-G442, Copyright © 1985 by American Physiological Society
Regulation of capillary exchange capacity in the dog stomach
M. A. Perry and D. N. Granger
The capillary exchange capacity of the isolated, perfused dog stomach was
investigated during vasoconstriction (norepinephrine) and vasodilation
(isoproterenol) and compared with values obtained when blood flow to the
stomach was decreased or increased mechanically. The capillary filtration
coefficient (Kf,c) was used as an index of capillary exchange capacity.
Under resting conditions, Kf,c in the isolated stomach was 0.20 +/- 0.02 ml
. min-1 . mmHg-1 . 100 g-1. Vasoconstriction and mechanical reduction in
blood flow caused Kf,c to fall to 68 and 58% of control, while vasodilation
and mechanical increase in blood flow caused Kf,c to rise to 176 and 231%
of control, respectively. Pentagastrin produced an increase in gastric
oxygen consumption and a 50% increase in Kf,c. In all instances, capillary
exchange capacity appeared to be correlated with gastric blood flow. The
data suggest there is little local control of precapillary sphincter tone
in the stomach and that capillary exchange capacity may be governed by
local pressure within the microvasculature.
