AJP - Regulatory, Integrative and Comparative Physiology, Vol 241, Issue 1 67-R71, Copyright © 1981 by American Physiological Society
Cardiac output distribution before and after endotoxin challenge in the rooster
G. F. Merrill, R. E. Russo and J. M. Halper
Cardiac output and its distribution to selected organs was studied using
radiolabeled microspheres in unanesthetized, restrained white Leghorn
roosters before and 3 h after an Escherichia coli endotoxin challenge.
Cardiac output was not significantly altered in either control or
endotoxin-treated animals, nor was there a difference in cardiac output
between the two groups. Systemic arterial pressure decreased by 37% in the
endotoxin group from 187 +/- 14 to 117 +/- 9 mmHg, thus reflecting a marked
reduction in total peripheral resistance. The fraction of cardiac output
perfusing the heart, adrenals, and liver (hepatic arterial) was not altered
by the challenge. Conversely, the percent of total blood flow received by
the kidneys, pancreas, and gut (proventriculus and duodenum) was
significantly (P less than 0.05) reduced during endotoxemia. Absolute flow
to the brain was also decreased. These findings demonstrate that in the
rooster endotoxin-induced systemic arterial hypotension is a sufficient
stress to cause a redistribution of blood flow, and that the brain in this
species (unlike its counterpart in mammals) probably regulates its blood
supply passively during periods of hypotension. Conversely, the reduced
blood supply to such organs as the gut, pancreas, and kidney following the
endotoxin challenge is similar to changes seen in the more commonly studied
mammals during experimental endotoxemia.
