Immunoelectron microscopic localization of endothelial nitric oxide synthase in human placental terminal villous trophoblasts-normal and pre-eclamptic pregnancy

We demonstrated the subcellular localization of endothelial nitric oxide sy nthase (eNOS) in human placental terminal villous trophoblasts at near term period, and compared the distribution pattern with that in pre-eclamptic t rophoblasts, using immunogold electron microscopy. Immunolabelling for eNOS was visible markedly in the syncytial microvilli and syncytial cytoplasm. Semiquantitative analysis showed that the concentration and the distributio n pattern of gold particles for cNOS did not significantly differ between n ormal and pre-eclamptic placental trophoblasts. These results indicated tha t syncytiotrophoblastic microvilli and cytoplasm were the subcellular local ization sites of syncytium-derived eNOS in terminal villi, and that there w ere no significant differences in this eNOS subcellular distribution patter n between normal and pre-eclamptic syncytiotrophoblasts in regard to immuno histochemically detectable eNOS. (C) 2001 Harcourt Publishers Ltd.