Stulc J, Stulcová B, Smíd M, Sach I
Department of Pharmacology, 2nd Faculty of Medicine, Prague, Czech Republic.
Am J Obstet Gynecol. 1994 Jan;170(1 Pt 1):162-7. doi: 10.1016/s0002-9378(94)70403-1.
We dissected the paracellular and transcellular components of Ca++ transfer across the perfused human placental cotyledon and explored the nature of the transcellular component.
Transfer of 45Ca++ and ethylenediaminetetraacetic acid labeled with chromium 51 was measured across the in vitro perfused cotyledon of the human placenta, and paracellular and transcellular components of the transfer of Ca++ were calculated from the transfer of the two tracers.
The transcellular component of the Ca++ transfer in the maternal-fetal direction represented about one third of the total maternal-fetal transfer. It was saturable, sensitive to cyanide, and insensitive to verapamil. The transcellular component in the fetal-maternal direction was not different from zero. The in vitro transfer rates correlated well with the transfer rates estimated for the in vivo situation from data published in the literature.
There is a significant active transport of Ca++ across the human placenta in the maternal-fetal direction.
我们剖析了钙离子跨灌注人胎盘小叶转运的细胞旁和跨细胞成分，并探究了跨细胞成分的性质。
测定了45钙离子和用铬51标记的乙二胺四乙酸跨人胎盘体外灌注小叶的转运情况，并根据两种示踪剂的转运计算出钙离子转运的细胞旁和跨细胞成分。
母胎方向钙离子转运的跨细胞成分约占母胎总转运量的三分之一。它具有饱和性，对氰化物敏感，对维拉帕米不敏感。胎儿-母体方向的跨细胞成分与零无差异。体外转运率与根据文献发表的数据估算的体内情况转运率密切相关。
在母胎方向上，钙离子跨人胎盘存在显著的主动转运。
