AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 5 670-G678, Copyright © 1986 by American Physiological Society
Microsphere method in measurement of blood flow to wall layers of small intestine
E. Dregelid, S. Haukaas, S. Amundsen, G. E. Eide, O. Soreide, J. Lekven and K. Svanes
Microspheres of 10.90 +/- 0.65 micron (SD) were injected in the superior
mesenteric artery of cats and their intramural distribution and diameter in
the small intestine were studied microscopically under basal conditions and
after vasodilation by isoproterenol. Approximately 2% of the spheres were
shunted through the small intestinal vasculature and could be recovered in
the liver. Analysis of the tissue distribution suggested that all spheres
arrested in villi represented villous blood flow, spheres arrested in the
crypt layer represented flow to the crypts, and the majority of
microspheres trapped in the submucosa also represented crypt flow.
Nutritive blood flow to the submucosa constituted only 1.5% of total
intestinal flow. Log-linear analyses identified factors responsible for
sphere distribution, including effects of sphere size, isoproterenol
treatment, and local blood flow or vascular resistance. Spheres with
diameters greater than 11.08 micron had 1.35 times larger odds than smaller
spheres to embolize in the muscularis rather than in the mucosa, but no
consistent difference between diameter profiles in the crypts and villi was
found. With this reservation, 11-micron spheres seem to be appropriate for
measuring blood flow to the muscle, crypt, and villous layers of the small
intestine.
