AJP - Gastrointestinal and Liver Physiology, Vol 247, Issue 4 357-G365, Copyright © 1984 by American Physiological Society
Cardiovascular and flux relationships in canine ileum
D. Mailman
Blood flow and pressure in denerved ileum of anesthetized dogs were altered
by occlusion of the mesenteric artery or vein or by infusion of
intra-arterial sodium nitroprusside (0.015-1.5 mg/min). Unidirectional Na
and H2O fluxes were measured and absorptive site blood flow was estimated
from the clearance of tritiated H2O. Net Na and H2O absorptions were
reduced by mesenteric venous or arterial occlusion. Net secretion occurred
with mesenteric venous occlusion. Nitroprusside reduced net absorption only
at an infusion rate of 0.15 mg/min. The absorptive Na and H2O fluxes were
reduced by both mesenteric venous or arterial occlusion, with venous
occlusion being more effective. Nitroprusside reduced the absorptive Na
flux at an infusion rate of 0.15 mg/min but not the absorptive H2O flux.
The secretory flux of Na was increased by mesenteric venous occlusion but
reduced by arterial occlusion and not changed by nitroprusside infusion.
The secretory H2O flux was decreased by moderate degrees of mesenteric
venous occlusion but was unchanged at greater levels. Arterial occlusion
decreased secretory H2O fluxes. Nitroprossude infusion increased secretory
H2O fluxes at an infusion rate of 0.015 mg/min. The absorptive and
secretory Na and H2O fluxes were significantly correlated with absorptive
site blood flow plus estimated capillary pressure. Absorptive site blood
flow was primarily responsible for changes in absorptive fluxes and
estimated capillary pressure for changes in secretory fluxes. Absorptive
site blood flow affected the secretory and absorptive fluxes of H2O more
equally than the Na fluxes.(ABSTRACT TRUNCATED AT 250 WORDS)
