AJP - Heart and Circulatory Physiology, Vol 240, Issue 3 361-H367, Copyright © 1981 by American Physiological Society
Regional blood flows in salt loading hypertension in the dog
J. F. Liard
An intravenous infusion of isotonic sodium chloride, 196 ml/kg per day, was
administered for several days to eight dogs with their renal mass reduced.
Mean arterial pressure, cardiac output (electromagnetic flowmeter), and
regional blood flows (radioactive microspheres) were measured sequentially
and the results compared with those obtained in six control dogs. The
salt-loaded animals exhibited on the 1st day of the infusion a 25% increase
of arterial pressure and cardiac output. Blood flows to the kidney, the
splanchnic area, the skin, and the bone were not significantly changed,
whereas skeletal muscle blood flow almost doubled. After several days,
cardiac output returned toward control values but pressure remained
elevated. Skeletal muscle blood flow, as most other regional flows, did not
differ significantly from control values at that time. In four dogs studied
6 h after starting a faster saline infusion, most of the increase in
cardiac output was also distributed to the skeletal muscle. Total
peripheral resistance changes did not reflect the resistance of individual
beds, because vasoconstriction appeared early in some areas but was masked
by prominent, although transient, vasodilation in skeletal muscle.
