Selective Vasodilator Effect of Magnesium Sulfate in Human Placenta

Authors

  • Gershon Holcberg,

    1. Division of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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  • Olga Sapir,

    1. Division of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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  • Mordechai Hallak,

    1. Division of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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  • Amash Alaa,

    1. Department of Microbiology and Immunology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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  • Haj-Yhia Shorok,

    1. Department of Microbiology and Immunology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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  • Yohay David,

    1. Division of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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  • Miriam Katz,

    1. Division of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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  • Mahmoud Huleihel

    1. Division of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
    2. Department of Microbiology and Immunology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
    3. Cancer Research Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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Address reprint requests to Gershon Holcberg, Division of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, PO Box 151, Beer Sheva 84101, Israel.
E-mail: holcberg@bgumail.ac.il

Abstract

Problems:  To determine if magnesium sulfate (MgSO4) attenuates the vasoconstrictor effect of angiotensin II (Ag II), endothelin-1 (ET-1) and thromboxane mimetic (TX) in the human fetal–placental vasculature and if interleukin-1 beta (IL-1β) is involved in this process.

Study design:  Isolated placental cotyledons (n = 18) were dually perfused with fetal perfusion pressure used as an index of vascular response. The vasoconstriction effect of bolus injection of various concentrations of Ag II (10−10–10−6 m) or ET-1 (10−10–10−4 m) or TX (10−10–10−5 m) was established in the absence or presence of MgSO4 (7 mg% constant infusion during 10 hr). Statistical significance was determined by paired t-test and anova.

Results:  MgSO4 significantly attenuates the vasoconstrictor effect of Ag II in the fetal–placental vasculature in the human placenta (P = 0.02). Moreover, significant attenuation of vasoconstrictor response to ET-1 (10−10–10−5 m) was observed in the presence of MgSO4 (P = 0.02). However, no attenuation of the vasoconstrictor response to TX was noted in the presence of MgSO4 (P > 0.5). Ag II and TX were shown to induce IL-1β secretion by placental tissue. This effect was completely reduced by perfusion of MgSO4 (7 mg%; constant infusion).

Conclusions:  MgSO4 significantly attenuates the vasoconstrictor effect of Ag II and ET-1 in the fetal–placental vasculature in the human placenta, but not that of TX. Inhibition of local production of IL-1β could be one of the mechanisms used by MgSO4 to reduce the vasoconstrictory effect of Ag II and TX in human placental cotyledone.

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