Developmental variations of brain serotonin, tryptophan, 5-hydroxyindole acetic acid, and noradrenaline and dopamine content in two inbred strains of mice.

Endogenous levels of tryptophan (TRP), serotonin (5-HT), 5-hydroxyindol acetic acid (5-HIAA), noradrenaline (NA) and dopamine (DA), were measured in the brain-stem and anterior regions of C57BL and BALBc mice whose ages ranged from 1 day postnatal to 12 weeks. In C57BL mice levels of NA were found to be higher in the brainstem from week 1 onwards (except at week 3), and in the anterior region from week 6 onwards than in BALBc mice. 5-HT levels were found to be higher in C57BL mice from day 1 to week 2 in the brain-stem, and in the anterior region at week 1 and from week 5 onwards, compared to BALBc. The evolution of DA levels in the anterior region shows opposite differences before and after week 3-4. Before week 3 lower levels of DA were found in C57BL mice and the reverse is observed from week 5 onwards. Moreover during the postnatal development, the variation of the different components of the serotoninergic metabolism (TRP, 5-HT, 5-HIAA) is similar to that observed in other species.