Hypertension, Vol 1, 389-396, Copyright © 1979 by American Heart Association
Y Otsuka, OA Carretero, R Albertini and A Binia
The purpose of this study was twofold: 1) to determine whether the failure
of rats with chronic renovascular hypertension to respond to the
angiotensin II antagonist (AIIA) with a decrease in mean blood pressure
(BP) was dur to the agonistic effect of the antagonist; and, 2) if this was
not the case, to examine whether a positive sodium balance impaired the
reversal of the hypertension, after unclamping, in the rats that did not
respond to angiotensin inhibitors. For this purpose, rats with chronic,
two-kidney Goldblatt hypertension (one renal artery clamped and
contralateral untouched) were tested for their BP response to the AIIA
(1-Sar-8-Ala-angiotensin II) and to the converting enzyme inhibitor (CEI)
SQ20,881, which is devoid of agonistic effect. Approximately 50% of the
rats responded to both inhibitors either with no change or with a decrease
in BP of less than 20 mm Hg (nonresponders). The other 50% had a decrease
in BP of 20 mm Hg or greater (responders). The decrease in BP produced by
the AIIA and the CEI correlated significantly (r = 0.76). Nonresponders to
both inhibitors were unclamped or sham unclamped. A positive sodium balance
was produced before surgery by injecting either 400 or 1000 microEq of
sodium and was maintained for 12 hours. Direct BP significantly decreased
12 hours after surgery in the unclamped rats despite a continuous positive
sodium balance. In the sham unclamped rats, BP did not change. These data
indicate that the failure to respond to the AIIA is not due to the
agonistic effect of this peptide. Furthermore, these data suggest that a
positive sodium balance is not a major pathogenetic factor in maintaining
the high BP in the nonresponder rats, since a positive sodium balance
failed to maintain the hypertension after unclamping.
ARTICLES
Angiotensin and sodium balance: their role in chronic two-kidney Goldblatt hypertension
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W. H. Beierwaltes, D'A. L. Potter, O. A. Carretero, and D. H. Sigmon Nitric Oxide Synthesis Inhibition Blocks Reversal of Two-Kidney, One Clip Renovascular Hypertension After Unclipping Hypertension, February 1, 1995; 25(2): 174 - 179. [Abstract] [Full Text] |
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