AJP - Heart and Circulatory Physiology, Vol 236, Issue 4 586-H591, Copyright © 1979 by American Physiological Society
Effect of DOCA-NaCl hypertension on pre- and postcapillary resistance in isolated hindlimbs of dogs
T. A. Brock and J. N. Diana
Measurements of precapillary resistance (Ra), postcapillary resistance
(Ra), postcapillary resistance (Rv), capillary filtration coefficient (Kf),
and mean capillary hydrostatic pressure (Pci) were made during
constant-flow perfusion of isolated hindlimbs from control and
deoxycorticosterone acetate (DOCA)-NaCl-treated hypertensive dogs by the
isogravimetric method. Both Ra and Rv were found to be significantly
increased in the hypertensive group, even after maximal vasodilatation with
papaverine. The net decreases in Ra and Rv following papaverine infusion
were not significantly different between control and hypertensive animals.
These results suggest that the observed increases in Ra and Rv were due to
structural adaptation (increased wall-to-lumen ratio). Nonpapaverinized
hindlimbs from hypertensive dogs exhibited a significant 40% reduction in
Kf, suggesting that capillary surface area for fluid exchange was
decreased. The compliance of the hindlimb vascular bed was found to be
significantly decreased in the hypertensive group. Pci of both groups of
hindlimbs were not different between groups and was not affected by
papaverine. This result suggests that net capillary permeability to plasma
proteins in this preparation was not changed by hypertension.
