Dopamine transporter mRNA in autopsy studies of chronic cocaine users.
The effects of chronic cocaine abuse on transcriptional regulation of human dopamine transporter (DAT) mRNA in midbrain dopaminergic neurons was assessed by reverse transcription-polymerase chain reaction (RT-PCR). DAT/cyclophilin mRNA ratios in the substantia nigra (SN) were unchanged in cocaine overdose (CO) victims as compared to age-matched and drug-free control (CTRL) subjects. In contrast, DAT mRNA levels were decreased significantly in agitated cocaine delirium victims (67%, p<0.05). These findings demonstrate the lack of a regulatory influence by cocaine on the steady state content of DAT mRNA in cocaine abusers. In contrast, DAT gene expression was altered significantly in cocaine abusers at risk for agitated delirium.