[Noradrenergic innervation of rat neocortex during development: immunocytochemical evidence using anti-dopamine-beta-hydroxylase antibodies].

Dopamine-beta-hydroxylase (DBH), the synthetizing enzyme for norepinephrine, has been visualized by immunofluorescence technique ontogeny in the Rat cerebral cortex. DBH like immunoreactive fibers develop as two bundles, one in the marginal zone observed at embryonic day 19 and another in the deep cortex visible at birth. These plexuses rapidly invade the whole neocortex following a rostro-caudal gradient. Five days after birth, all cortical layers show DBH containing fibers but the adult pattern is only reached two weeks after birth.