Postnatal development of dopamine and serotonin transporters in rat caudate-putamen and nucleus accumbens septi.

Density of dopamine transporter (DAT) and serotonin transporter (5-HTT) membrane proteins in the caudate-putamen (CPu) and nucleus accumbens (NAc) of rat brain was assessed at seven ages at postnatal days (PD) 7-60, by in vitro quantitative autoradiography. Binding of [3H]GBR-12935 (to DAT) and [3H]paroxetine (to 5-HTT) increased steadily and very similarly, from low levels at PD-7 to maximal levels, to 6-7-fold higher density at PD-60 in both regions. These findings indicate that DAT and 5-HTT follow a synchronized course of development in rat CPu and NAc. In contrast to reported elimination of excessive receptors in CPu and NAc during maturation, there was no evidence of pruning of DAT or 5-HTT in these regions of rat forebrain.