[Expression of endothelial nitric oxide synthase mRNA in human placenta].

OBJECTIVE: To determine the localization and type of nitric oxide synthase in human placenta.

METHODS: By polymerase chain reaction and in situ hybridization. The eNOS mRNA expression was observed in 10 cases of human normal term placenta and cord.

RESULTS: In human normal term placenta, positive staining of eNOS was evident in the syncytiotrophoblast and the endothelium of umbilical artery and vein, positive staining also presented in the endothelium of stem villous vessels, but it was absent in the endothelium of terminal villous capillary.

CONCLUSION: eNOS is present in syncytiotrophoblast and endothelium of stem villi vessels, and it can synthesize nitric oxide which results in the increase of nitric oxide in pregnancy.