IMMUNOHISTOCHEMICAL LOCALIZATION OF NITRIC-OXIDE SYNTHASE IN HUMAN FETAL MEMBRANES

Subject. It has been demonstrated that L-arginine-nitric oxide (NO) sy stem is present in the myometrium during pregnancy where it can regula te uterine contractility. Material and method. We have studied by immu nohistochemistry the localization of constitutive endothelial nitric o xide synthase (ecNOS) and brain nitric oxide synthase (bNOS) in human fetal membranes in term non laboring women. Results. The amniotic epit helium and the trophoblast of chorion layer stained intensively for bN OS, while for ecNOS the immunoreactivity uas weak and restricted to tr ophoblast cells. Conclusion. These findings are suggestive for NO prod uction by the fetal membranes in term pregnancy.