DEVELOPMENT OF ENDOTHELIAL NITRIC-OXIDE SYNTHASE IN ENDOTHELIAL-CELLSIN THE HUMAN CEREBRUM

We demonstrate the distribution and development of endothelial nitric oxide synthase (eNOS) immunoreactivity in vessels of the human brain. eNOS-positive endothelial cells were recognized in small vessels in th e parenchyma of the cerebrum, as well as in the large arteries and vei ns in the leptomeninges. By 10-13 weeks of gestation, eNOS-positive en dothelial cells had already appeared in the vessels of the leptomening es and deep white matter. Immunoreactivity for eNOS was noted in most vessels at 14-17 weeks in the intermediate white matter, at 18-21 week s in the cortex, and at 23-26 weeks in the subcortical white matter. S uch differences in regional development may be responsible in part for the topographical predilection for hemorrhagic or hypoxic-ischemic le sions in the developing brain.