AJP - Gastrointestinal and Liver Physiology, Vol 245, Issue 1 29-G37, Copyright © 1983 by American Physiological Society
Simultaneous estimation of arteriolar, capillary, and shunt blood flow of the gut mucosa
P. K. Dinda, M. G. Buell, L. R. DaCosta and I. T. Beck
Microspheres of 15 and 9 microns diameter were injected simultaneously into
the left ventricle of the dog, and the entrapment of these microspheres in
different layers of the gut wall was measured under resting conditions,
vasoconstriction, and subsequent vasodilation. Results show that some of
the 9-microns spheres passed into the portal blood through all layers of
the gut wall, whereas 15-microns spheres were completely entrapped in the
tissue. The pattern of entrapment of 15-microns spheres during
vasoconstriction and during subsequent vasodilation suggests that these
microspheres measure adequately the arteriolar inflow of the muscularis,
submucosa, and mucosa (i.e., villus plus crypt) but, due to series
arrangement between the arterioles of the villus and the crypt, cannot
measure the arteriolar flow of the villus and crypt separately. The
entrapment of 9-microns microspheres in the muscularis, submucosa, crypt,
and villus that occurred during vasoconstriction did not change during
subsequent vasodilation. This suggests that these microspheres became
lodged in the precapillary sphincter or capillary and therefore measured
the capillary flow of these layers. Accordingly, the difference between the
arteriolar (measured by 15 microns) and the capillary (measured by 9
microns) flow of the muscularis, submucosa, and mucosa may provide an
estimate of the noncapillary (shunt) flow of these layers.
