AJP - Heart and Circulatory Physiology, Vol 236, Issue 1 92-H95, Copyright © 1979 by American Physiological Society
Plasma volumes and hematocrits in rats with chronic sinoaortic denervation hypertension
N. Alexander
Plasma volume changes were assessed in female Wistar rats with neurogenic
hypertension induced by sinoaortic denervation, SAD. Tail veins of
conscious, restrained rats were used for injection of Evans blue dye and
for sampling into microhematocrit tubes. Only at 3 days did total plasma
volume of SAD rats show a modest reduction of about 16% (P less than 0.05
vs. sham-operated plus unoperated controls). At 3, 6, and 13 wk, SAD mean
body weight, plasma volume, and sodium concentration were similar to sham
values. SAD hematocrits, however, like arterial pressures, were elevated at
all postoperative times studied. In anesthetized SAD and sham rats, red
blood cell (51Cr method) and plasma volumes were the same and so were
hematocrits. The latter was unlike the finding in unanesthetized groups.
Hematocrits from the same SAD rats were lower after induction of anesthesia
than before (P less than 0.025). Thus, elevated hematocrits apparently
resulted from the release of sequestered red blood cells into the
circulation by unanesthetized SAD rats. In conclusion, plasma volume is
within the normal range in SAD rats except for the first few postoperative
days. Factors affecting volume regulation at that time are discussed.
