AJP - Heart and Circulatory Physiology, Vol 249, Issue 4 859-H866, Copyright © 1985 by American Physiological Society
Increased arteriolar wall-to-lumen ratio in a normotensive vascular bed in coarctation hypertension
W. C. Plunkett and H. W. Overbeck
In rats with coarctation hypertension, resting resistance and resistance at
maximal vasodilation are elevated in the hindquarters, although blood
pressure in this vascular bed remains normal. To assess the nature of these
non-pressure-related vascular abnormalities, we observed third- to
fifth-order arterioles in the cremaster microcirculation using standard
techniques and chloralose-urethan anesthesia in rats with coarctation or
sham coarctation of the abdominal aorta. Four weeks after clipping, carotid
pressure was significantly elevated in coarcted compared with sham-coarcted
rats, but femoral pressure was not. The wall-to-lumen ratio and wall
thickness in cremaster arterioles was elevated by 12-33% in coarcted
compared with sham-coarcted rats in the resting state. After maximal
arteriolar relaxation with topical nitroprusside, differences in
wall-to-lumen ratio persisted. We also studied the microcirculation of
one-kidney normotensive control and one-kidney, one-clip Goldblatt
hypertensive rats. Femoral pressure in Goldblatt hypertensive rats was
elevated, but changes in the microcirculation were similar to those
observed in coarcted rats. These non-pressure-related changes in vascular
structure in hypertension may result from systemic neural or humoral
influences and/or growth factors local to vascular wall tissues.
