AJP - Gastrointestinal and Liver Physiology, Vol 246, Issue 5 521-G527, Copyright © 1984 by American Physiological Society
Arachidonic acid and postprandial intestinal hyperemia
M. J. Mangino and C. C. Chou
The effects of prostaglandin synthesis on food-induced increases in
intestinal blood flow and O2 uptake were examined in the jejunum of
anesthetized dogs. Intravenous (40 micrograms X kg-1 X min-1) or
intra-arterial (0.8-1.6 microgram X min-1) infusions and luminal placement
(6.5 X 10(-4) M or 200 micrograms/ml) of arachidonic acid (AA)
significantly attenuated the food-induced jejunal hyperemia. Furthermore,
luminal placement of AA significantly attenuated the food-induced increase
in jejunal O2 uptake. Changes in blood flow and O2 uptake were
significantly correlated both before and after arachidonic acid
administration. Although intravenous infusion of AA decreased blood flow,
intra-arterial infusion and luminal placement of AA did not significantly
alter resting blood flow under free-flow conditions. In another series of
experiments, intravenous infusions of AA under constant-flow conditions
produced a biphasic response: vascular resistance rose when local blood AA
concentration was raised to the range between 1 and 6 micrograms/ml blood
and fell when the concentration was raised between 8 and 12 micrograms/ml
blood. This study indicates that prostaglandin synthesis has a marked
effect on both resting intestinal blood flow and postprandial intestinal
hyperemia. The attenuation of the hyperemia may be due to its attenuation
of the food-induced increase in intestinal oxidative metabolism.
