TY - JOUR
T1 - Effect of hypertonic saline on vascular responses to angiotensin II in pregnancy
AU - Matsuura, Shumpei
AU - Naden, Raymond P.
AU - Gant, Norman F.
AU - Parker, C. Richard
AU - Rosenfeld, Charles R.
N1 - Funding Information:
From the Departments of Pediatrics, Obstetrics and Gynecology, and Physiology, The University of Texas Health Science Center at Dal-las, Southwesta Medical School. Supported by National Institutes of Health Grants No. 2 ROl HDO8783 and No. ROI HDO8360. Received for publication March 1 I, 1983. Accepted May 2, 1983. Reprint requests: Charles R. Rosenfeld, M.D., Department of Pediatrics, Southwestern Medical School, 5323 Harry Hines Blvd.. Dallas, Texas 75235.
PY - 1983/10/1
Y1 - 1983/10/1
N2 - Refractoriness to infused angiotensin II is characteristic or normal human and ovine pregnancy; the mechanisms responsible are unclear. In this study, we sought to ascertain in gravid sheep whether hypertonic saline solution alters the vascular responses to angiotensin II, as in gravid women, and to compare the responses of the systemic and uteroplacental vasculature. Dose-response curves were determined. Mean arterial pressure and systemic vascular resistance increased in a dose-dependent fashion before and after hypertonic saline solution; responses were greater after hypertonic saline solution (p < 0.01). Responses of cardiac output, heart rate, uterine vascular resistance, and uterine blood flow also were dose-dependent, but were unchanged after hypertonic saline solution. Plasma renin activity fell 45% after hypertonic saline solution. Treatment with hypertonic saline solution results in increased pressor responses to angiotensin II that are not a reflection of altered baroreceptor or chemoreceptor reflexes or of the response in the uteroplacental vascular bed. Rather, the increased systemic vascular responsiveness to angiotensin II after hypertonic saline solution appears to be a reflection of other mechanisms, such as alterations in vessel wall dynamics or receptor affinity.
AB - Refractoriness to infused angiotensin II is characteristic or normal human and ovine pregnancy; the mechanisms responsible are unclear. In this study, we sought to ascertain in gravid sheep whether hypertonic saline solution alters the vascular responses to angiotensin II, as in gravid women, and to compare the responses of the systemic and uteroplacental vasculature. Dose-response curves were determined. Mean arterial pressure and systemic vascular resistance increased in a dose-dependent fashion before and after hypertonic saline solution; responses were greater after hypertonic saline solution (p < 0.01). Responses of cardiac output, heart rate, uterine vascular resistance, and uterine blood flow also were dose-dependent, but were unchanged after hypertonic saline solution. Plasma renin activity fell 45% after hypertonic saline solution. Treatment with hypertonic saline solution results in increased pressor responses to angiotensin II that are not a reflection of altered baroreceptor or chemoreceptor reflexes or of the response in the uteroplacental vascular bed. Rather, the increased systemic vascular responsiveness to angiotensin II after hypertonic saline solution appears to be a reflection of other mechanisms, such as alterations in vessel wall dynamics or receptor affinity.
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U2 - 10.1016/0002-9378(83)91103-1
DO - 10.1016/0002-9378(83)91103-1
M3 - Article
C2 - 6624788
AN - SCOPUS:0020512539
SN - 0002-9378
VL - 147
SP - 231
EP - 240
JO - American journal of obstetrics and gynecology
JF - American journal of obstetrics and gynecology
IS - 3
ER -