AJP - Gastrointestinal and Liver Physiology, Vol 249, Issue 6 685-G690, Copyright © 1985 by American Physiological Society
Effect of atropine on digested food-induced intestinal hyperemia
R. A. Nyhof, D. Ingold-Wilcox and C. C. Chou
The aim of our study was to determine whether the discrepancy in the data
reported on the effect of atropine on food-induced intestinal hyperemia
results from a difference in experimental materials and methods. In the
first two series of experiments, atropine (0.5 mg/kg iv) was given before
or during intraluminal perfusion of digested food plus bile through a long
jejunal loop (62% of the total small intestine) at 4 ml/min for 60 min
while measuring the portion of the blood flow through the superior
mesenteric artery (SMA) that perfused the loop. Atropine per se had no
effect on jejunal blood flow. Before atropine food increased flow 31.5 +/-
10.1% and after atropine flow increased 54.8 +/- 11.0 and 66.0 +/- 28.0%
above controls in the first and second series, respectively. Atropine also
increased net fluid volume absorption. In the third series, food alone and
food plus bile were placed into the lumens of the two adjacent jejunal
segments. Atropine had no effect on the increases in flow and oxygen uptake
produced by food alone but enhanced the hyperemia produced by food plus
bile without affecting the increase in oxygen uptake. Our results suggest
that the previously reported inhibition of increased SMA flow by atropine
is due to the inhibitory effect of atropine on gastrointestinal motility
and inhibition of pancreatic blood flow. In conclusion, food-induced
jejunal hyperemia does not result from a direct vasodilator action of the
cholinergic nerves.
