The development of neocortical noradrenergic innervation in the mouse: a quantitative radioenzymatic analysis

The concentration of norepinephrine (NE) in the neocortex of the mouse has been determined radioenzymatically from the thirteenth embryonic (E13) through the sixtieth postnatal (P60) days. Detectable levels of the transmitter are present on E14, coincident with the emergence of the cortical plate. NE concentrations increase rapidly thereafter to reach a level 57% of adult values by P4. Subsequently, through P8 there is a decline followed again by a more gradual rise to maximum, or adult, concentrations by P30.