Increased peripheral resistance during reduced uterine perfusion pressure hypertension in pregnant rabbits

G. Losonczy, G. Brown, R. C. Venuto

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Abstract

The role of an increase in total peripheral resistance (TPR) and the contribution of angiotensin II (ANG II) to the hypertension induced by reduced uterine perfusion pressure (RUPP) was explored in pregnant rabbits. On the 22nd day of gestation, a catheter and a microthermocouple were placed in the aorta to measure mean arterial pressure (MAP) and cardiac output (CO), respectively. Three days later, RUPP was induced by a clip on the aorta proximal to the ovarian and distal to the renal arteries. Mean arterial pressure distal to the clip (uterine perfusion pressure) was reduced to 56 ± 8% (x̄ ± SD) of the initial level. Twenty-four hours later, MAP rose from 65 ± 3 to 84 ± 11 mm Hg; CO index decreased from 207 ± 18 to 169 ± 27 ml/min/kg; and TPR index increased from 0.32 ± 0.03 to 0.51 ± 0.08 mm Hg kg/ml/min, respectively (n = 7, all p < 0.01). Sham-operated pregnant rabbits (n = 7) an non-P rabbits (n = 5) with a comparable distal aortic pressure reduction experienced no change in MAP or CO. Infusion of a receptor antagonist of angiotensin II (Sar1, Ile8-Ang II, 1 μg/kg/min for 20 min) decreased MAP in sham-operated pregnant rabbits from 64 ± 6 to 54 ± 6 mm Hg (p < 0.01) but did not change MAP in RUPP hypertensive rabbits (86 ± 9 mm Hg before and 87 ± 8 at the end of infusion, n = 6. These data indicate that RUPP in pregnant rabbits leads to a high resistance form of hypertension in which the formation of Ang II is not increased.

Original languageEnglish
Pages (from-to)233-240
Number of pages8
JournalAmerican Journal of the Medical Sciences
Volume303
Issue number4
DOIs
Publication statusPublished - Jan 1 1992

Keywords

  • Angiotensin in pregnancy
  • Blood pressure in pregnancy
  • Uteroplacental ischemia

ASJC Scopus subject areas

  • Medicine(all)

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