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Prostaglandin synthesis via dopamine receptors by human decidua
A.82
Placenfa (I 994). Vol I5
PROSTAGLANDIN SYNTHESIS VIA DOPAMINE RECEPTORS BY HUMAN DECIDUA. Yuji Kondo, Yasuo Kishimoto, Katsuhiko Tada, Takumi Yanagawa, Yoshiaki Nakatani, Fujimi Arai and Takafumi Kudo, Department of Obstetrics and Gynecology, Okayama University Medical School, Okayama, Japan. We have reported that dopamine(DA) in amniotic fluid increases markedly at term and DA-receptors exist in human decidua. Then, we studied the stimulatory effect of DA on prostaglandin(PG) synthesis by human decidua. Decidual tissues obtained at the time of elective cesarean sections were incubated in Krebs-Ringer bicarbonate for 30 min at 37°C. PGF in the medium was measured using RIA. When DA was added, the rate of increase in PGF concentration was significantly greater than that of the control. Addition of D&-antagonist (sulpiride) caused a significant decrease of DA-induced PGF production. These results suggest that DA in amniotic fluid stimulates PG synthesis by human decidua via DA%dopamine receptors.
MECHANISMS OF TRANSEPITHELIAL TRANSPORT OF AMINO ACIDS IN HUMAN PLACENTA. Yoshiki Kudo, Department of Obstetrics and Gynecology, Tokyo Women’s Medical College, Tokyo, Japan. All placental transfer of amino acids from mother to fetus must occur across the syncytiotrophoblast. The maternal-facing surface (brush border membrane) and the fetal-facing surface (basal membrane) of this epithelium possess marked structural and functional polarity. solated plasma membrane vesicles were prepared respectively from the maternal-facing brush border and fetalfacing basal surface of the human full-term placental syncytiottophoblast. Using these membrane preparations, transport studies were carried out to explore the mechanisms of transepithelial transfer of amino acids from mother to fetus. These studies indicate marked differences in the distribution of amino acid transport systems between the brush border and basal surface of the human syncytiotrophoblast. This asymmetry may explain net transplacental transfer of amino acids to the fetus; thus sodium ion dependent active transport systems or systems with trans-stimulation generate up hill transfer of amino acids at the brush border surface and facilitated or passive diffusion driven by the amino acid concentration gradient is responsible for the basal membrane exit step. Such mechanisms may underlie the observed gradients of amino acid concentration across the placenta, fetal concentrations being consistently higher than maternal.
Placenfa (I 994). Vol I5
PROSTAGLANDIN SYNTHESIS VIA DOPAMINE RECEPTORS BY HUMAN DECIDUA. Yuji Kondo, Yasuo Kishimoto, Katsuhiko Tada, Takumi Yanagawa, Yoshiaki Nakatani, Fujimi Arai and Takafumi Kudo, Department of Obstetrics and Gynecology, Okayama University Medical School, Okayama, Japan. We have reported that dopamine(DA) in amniotic fluid increases markedly at term and DA-receptors exist in human decidua. Then, we studied the stimulatory effect of DA on prostaglandin(PG) synthesis by human decidua. Decidual tissues obtained at the time of elective cesarean sections were incubated in Krebs-Ringer bicarbonate for 30 min at 37°C. PGF in the medium was measured using RIA. When DA was added, the rate of increase in PGF concentration was significantly greater than that of the control. Addition of D&-antagonist (sulpiride) caused a significant decrease of DA-induced PGF production. These results suggest that DA in amniotic fluid stimulates PG synthesis by human decidua via DA%dopamine receptors.
MECHANISMS OF TRANSEPITHELIAL TRANSPORT OF AMINO ACIDS IN HUMAN PLACENTA. Yoshiki Kudo, Department of Obstetrics and Gynecology, Tokyo Women’s Medical College, Tokyo, Japan. All placental transfer of amino acids from mother to fetus must occur across the syncytiotrophoblast. The maternal-facing surface (brush border membrane) and the fetal-facing surface (basal membrane) of this epithelium possess marked structural and functional polarity. solated plasma membrane vesicles were prepared respectively from the maternal-facing brush border and fetalfacing basal surface of the human full-term placental syncytiottophoblast. Using these membrane preparations, transport studies were carried out to explore the mechanisms of transepithelial transfer of amino acids from mother to fetus. These studies indicate marked differences in the distribution of amino acid transport systems between the brush border and basal surface of the human syncytiotrophoblast. This asymmetry may explain net transplacental transfer of amino acids to the fetus; thus sodium ion dependent active transport systems or systems with trans-stimulation generate up hill transfer of amino acids at the brush border surface and facilitated or passive diffusion driven by the amino acid concentration gradient is responsible for the basal membrane exit step. Such mechanisms may underlie the observed gradients of amino acid concentration across the placenta, fetal concentrations being consistently higher than maternal.