Hypertension, Vol 12, 373-379, Copyright © 1988 by American Heart Association
TO Myers, WL Joyner and JP Gilmore
Increased reactivity to vasoconstrictor agents and decreased arteriolar
luminal diameter have been implicated in the maintenance of hypertension.
The same hamster cheek pouch microvessels were tested for angiotensin I
(Ang I) and angiotensin II (Ang II) reactivity before and 10 to 14 days
after Grollman (two-kidney, one figure-8) or sham operation. Microvascular
geometric parameters were measured before and after a maximal vasodilator
dose of adenosine. Then maximal vasoconstrictions to Ang I or Ang II were
measured: Ang I and Ang II were applied adjacent to arterioles
(10(-2)-10(0) pmol) and venules (10(-1) pmol) in 10-microliter aliquots for
1 minute. Blood pressure (178 +/- 11/133 +/- 8 mm Hg) of renovascular
hypertensive hamsters was elevated significantly over blood pressure of
sham-operated hamsters (120 +/- 11/97 +/- 10 mm Hg). No change was observed
in venular geometry or reactivity in renovascular hypertensive hamsters.
Arteriolar luminal diameter, wall thickness, wall/lumen ratio, and wall
area were not altered in hypertensive hamsters in the normal or vasodilated
state; vasodilator capacity was the same in all groups. Conversion of Ang I
to Ang II (response to Ang I divided by response to Ang II) for first-order
and Third-order arterioles and third-order venules was 74 +/- 5, 79 +/- 3,
and 72 +/- 6%, respectively, and was unaltered in renovascular hypertensive
hamsters. Although vessel geometry was not altered, there was a significant
shift to the left of the Ang I and Ang II dose-response curves of
first-order and third- order arterioles, indicating increased sensitivity
to these vasoconstrictors.(ABSTRACT TRUNCATED AT 250 WORDS)
ARTICLES
Angiotensin reactivity in the cheek pouch of the renovascular hypertensive hamster
Department of Physiology and Biophysics, University of Nebraska College of Medicine, Omaha 68105-1065.
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