Hypertension, Vol 10, 82-92, Copyright © 1987 by American Heart Association
DL Stacy, WL Joyner and JP Gilmore
The responses to alterations in extravascular pressure were studied in five
orders of arterioles in the cheek pouch of normotensive and renal
hypertensive hamsters. Renal hypertension was induced by bilateral
compression of both kidneys using figure-of-eight ligatures. Ten to 16 days
later, hamsters were anesthetized with pentobarbital (6.0 mg/100 g body
weight) and a Plexiglas chamber was positioned in the cheek pouch. Chamber
pressure, or extravascular pressure, was increased and decreased by +/- 10,
20, and 40 mm Hg, and arteriolar diameters were monitored continuously. The
responses at -20 mm Hg and the slope of the linear portion of the chamber
pressure-diameter curve (arteriolar gains) were compared between groups for
each branching order of arteriole. Arteriolar responses at one chamber
pressure and the arteriolar gains were enhanced in third and fourth order
arterioles of the renal hypertensive group compared with the normotensive
group, and the responses of these small arterioles were greater than those
of larger arterioles in both groups. Control diameters of second and third
order arterioles were significantly smaller in the renal hypertensive
group, while the diameters after adenosine were not different. These
results suggest that the enhanced responses of small arterioles in the
renal hypertensive group were not related to structural alterations but may
be related to an increased reactivity of smooth muscles in these small
arterioles to volume expansion, thus a pressure stimulus.
ARTICLES
Arteriolar reactivity to pressure stimuli in hamsters with renal hypertension
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