Hedley R, Bradbury M W
Placenta. 1980 Oct-Dec;1(4):277-85. doi: 10.1016/s0143-4004(80)80029-4.
The permeability of the mature placenta of the guinea-pig has been measured to several polar non-electrolytes of differing molecular weights and to two cations. Two methods were used: on the one hand, direct analysis of the fetus after it has taken up labelled solutes from maternal blood, and, on the other, perfusion of the umbilical circulation in situ. In the intact condition, fluorescein dextran of 3000 molecular weight and 51Cr-EDTA permeated from mother to fetus at rates proportional to their free diffusion coefficients in water, indicating the presence of large pores. Perfusion of the umbilical circulation with a physiological salt solution containing dextran increased permeability to these two solutes and hence total pore area three to four times. The movement of 14C-erythritol, 24Na and 42K was such as to suggest that they also cross the placenta by an additional route (or routes), which is not enchanced by perfusion. This route presumably traverses the plasma membranes of the syncytiotrophoblast.
已对豚鼠成熟胎盘对几种不同分子量的极性非电解质和两种阳离子的通透性进行了测量。使用了两种方法：一方面，在胎儿从母体血液中摄取标记溶质后对其进行直接分析；另一方面，对原位脐循环进行灌注。在完整状态下，分子量为3000的荧光素葡聚糖和51Cr - 乙二胺四乙酸从母体渗透到胎儿的速率与其在水中的自由扩散系数成正比，表明存在大孔。用含有葡聚糖的生理盐溶液灌注脐循环会使对这两种溶质的通透性增加，从而使总孔面积增加三到四倍。14C - 赤藓醇、24Na和42K的移动情况表明它们也通过一条额外的途径（或多条途径）穿过胎盘，灌注并不会增强这种途径。这条途径大概穿过合体滋养层的质膜。
