The dopamine transporter (DAT) in rat striatum was examined during pos
tnatal development and aging after photolabeling with [I-125]DEEP. The
DAT-[I-125]DEEP protein complex from adult rats (2 months) appeared a
s a broad diffuse band in SDS-PAGE gels with average apparent molecula
r mass of about 80,000 Da as previously found. However, the molecular
mass was lower at birth (day 0) and at postnatal ages 4 and 14 days. I
n aged rats (104 weeks), the molecular mass was slightly higher than t
hat found in young adults (60 days). In binding experiments with [H-3]
BTCP, there were age-related differences in K-d and B-max with decreas
es in both K-d and B-max found in aged rats. Treatment of photolabeled
membranes with neuraminidase caused a reduction in DAT molecular mass
, but age-related differences were maintained. Treatment with N-glycan
ase greatly reduced or eliminated the age-related differences. Several
DAT peptide-specific polyclonal antibodies immunoprecipitated DAT[I-1
25]DEEP protein complex at different developmental ages. Taken togethe
r, these results suggest differential glycosylation of rat DAT occurs
during postnatal development and aging; the increase is due to increas
es in the N-linked sugars rather than changes in either sialic acid co
ntent or the polypeptide.