Baroreflex sensitivity and susceptibility to systolic hypertension induced by DOCA-salt in the Sabra rat

M. Weinstock, D. Schorer-Apelbaum, D. Ben-Ishay

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15 Scopus citations

Abstract

Rats of salt-resistant Sabra strain (SBN) have a more sensitive baroreflex control of heart rate than do normotensive hypertension-prone salt-sensitive (SBH) rats. To test the hypothesis that increased baroreflex sensitivity confers resistance to hypertension, aortic baroreflex deafferentation (ABD) was performed in 7- to 10-wk-old SBN rats. This treatment reduced the slope of the mean arterial pressure-heart period (MAP-HP) relationship in response to infusion of increasing doses of phenylephrine in conscious rats, from 1.92 ± 0.21 to 0.66 ± 0.11 ms·mmHg-1 (P < 0.01). The latter value did not differ significantly from that of untreated SBH rats (0.56 ± 0.07 ms·mmHg-1). Treatment of uniphrectomized SBH, SBN-ABD, and sham-operated SBN rats for 3 wk with deoxycorticosterone acetate (DOCA; 25-mg pellet) and 0.9% NaCl + 0.4% KCl (to maintain normal serum K+ values) as drinking fluid caused increases in systolic blood pressure from 126 ± 3 to 147 ± 5 mmHg and 104 ± 6 to 130 ± 8 mmHg in the former two groups, respectively, but no significant change (105 ± 3 to 110 ± 4 mmHg) in SBN rats when measured by an indwelling arterial catheter in the tail artery. The slopes of the MAP-HP relationships of each of the above three groups of rats were not significantly altered by DOCA-salt treatment. It is concluded that a decrease in baroreflex control of the heart by ABD can render SBN rats sensitive to DOCA-salt-induced systolic hypertension.

Original languageEnglish
Pages (from-to)H448-H452
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume15
Issue number3
DOIs
StatePublished - 1984

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