K. Dikranian et al., NITRIC-OXIDE SYNTHASE (NOS) IN THE HUMAN UMBILICAL-CORD VESSELS - AN IMMUNOHISTOCHEMICAL STUDY, Acta histochemica, 96(2), 1994, pp. 145-153
Localization of nitric oxide synthase (NOS) in endothelial cells of um
bilical cord vessels and in cultured human umbilical vein endothelial
cells was investigated by light and electronmicroscopical (immunogold)
immunohistochemistry. We observed localization of NOS-immunoreactivit
y in the majority (97%) of the endothelial cells of the umbilical vein
and in a subpopulation (6.7%) of endothelial cells of the umbilical a
rteries. NOS was observed as well in the amniotic epithelium and in th
e cells of Wharton's jelly. Immunogold labelling in human umbilical ve
in endothelial cells dominated in the cellular matrix and was not asso
ciated with cellular organelles. Since human umbilical vessels are uni
que in lacking innervation, the functional significance of endothelium
derived relaxing factor EDRF/NO in the local control of vascular flow
is discussed.