C. Perronecapano et al., DOPAMINE TRANSPORTER GENE-EXPRESSION IN RAT MESENCEPHALIC DOPAMINERGIC-NEURONS IS INCREASED BY DIRECT INTERACTION WITH TARGET STRIATAL CELLS IN-VITRO, Molecular brain research, 39(1-2), 1996, pp. 160-166
By using a semi-quantitative reverse transcriptase-PCR assay (RT-PCR)
we have analyzed dopamine transporter (DAT), tyrosine hydroxylase (TH)
and synaptic vesicle monoamine transporter (VMAT2) gene expression in
rat mesencephalic (MES) primary cultures. Consistent with previous da
ta obtained during rat MES ontogeny, the onset of DAT transcription in
vitro is delayed in embryonic day (E)13, but not in E16, MES neurons
when compared to that of TH and VMAT2. In co-culture, the addition of
target striatal cells (STR) to E13 MES selectively increases DAT mRNA
level in DA neurons during the first 3 days in vitro; cortical cells a
re ineffective. On the contrary, DAT gene does not appear up-regulated
in E16 MES co-cultured with target STR cells, indicating that MES DA
neurons respond to STR stimulation only at defined developmental stage
s. Up-regulation of DAT mRNA level by STR in E13 MES seems to require
direct cell interactions since target cells do not exert their effect
on DAT transcription when are separated from MES cells by a porous bar
rier, which only allows diffusion of soluble molecules. Thus maturatio
n of DA neurotransmission in vitro appears to follow a developmental p
rogram which can be specifically modulated by their target STR cells.