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Selective Vasodilator Effect of Magnesium Sulfate in Human Placenta
Author(s) -
Holcberg Gershon,
Sapir Olga,
Hallak Mordechai,
Alaa Amash,
Shorok HajYhia,
David Yohay,
Katz Miriam,
Huleihel Mahmoud
Publication year - 2004
Publication title -
american journal of reproductive immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.071
H-Index - 97
eISSN - 1600-0897
pISSN - 1046-7408
DOI - 10.1111/j.1600-0897.2004.00115.x
Subject(s) - placenta , endocrinology , perfusion , medicine , vasodilation , vasoconstriction , fetus , angiotensin ii , chemistry , thromboxane a2 , endothelin 1 , fetal membrane , bolus (digestion) , vasoconstrictor agents , magnesium , biology , blood pressure , pregnancy , receptor , genetics , organic chemistry
Problems: To determine if magnesium sulfate (MgSO 4 ) 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‐1 β ) 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 MgSO 4 (7 mg% constant infusion during 10 hr). Statistical significance was determined by paired t ‐test and anova . Results: MgSO 4 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 MgSO 4 ( P = 0.02). However, no attenuation of the vasoconstrictor response to TX was noted in the presence of MgSO 4 ( P > 0.5). Ag II and TX were shown to induce IL‐1 β secretion by placental tissue. This effect was completely reduced by perfusion of MgSO 4 (7 mg%; constant infusion). Conclusions: MgSO 4 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‐1 β could be one of the mechanisms used by MgSO 4 to reduce the vasoconstrictory effect of Ag II and TX in human placental cotyledone.