Postnatal development of noradrenaline and 3-methoxy-4-hydroxyphenylethyleneglycol sulphate levels in rat brain regions.

Developmental changes in brain levels of noradrenaline (NA) and 3-methoxy-4-hydroxyphenylethyleneglycol sulphate (MHPG-SO4) were studied in rats. In most brain regions, MHPG-SO4 level rapidly increased to approach or exceed adult levels at the time of weaning, while NA levels increased more gradually and reached adult levels following weaning. Pharmacological studies showed that the MHPG-SO4 level in the neonatal brain reflects the degradation of released NA. The developmental characteristics of noradrenergic neurons in eight discrete brain regions are discussed.