The expression of the human dopamine D-1 receptor was examined by reverse t
ranscription polymerase chain reaction (RT-PCR) and radioligand binding usi
ng [H-3]-SCH23390 in post-mortem brain tissue that was obtained from normal
subjects and patients dying with Parkinson's disease who were receiving tr
eatment with dopaminergic drugs. D-1 receptor mRNA and specific [H-3]-SCH23
390 binding sites were found in both striatal (nucleus accumbens, caudate n
ucleus and putamen) and extrastriatal (globus pallidus and substantia nigra
) brain regions. In parkinsonian brain, D-1 receptor mRNA was increased in
the nucleus accumbens, while a decrease was detected in the substantia nigr
a pars compacta. No change in D-1 mRNA levels was found in the other brain
areas examined. An increase in the density of specific [H-3]-SCH23390 bindi
ng sites was found in the anterior putamen and a decrease in the external s
egment of the globus pallidus, no changes were detected elsewhere. This stu
dy demonstrates that regulation of D-1 receptor expression in the brain of
patients dying with Parkinson's disease that were treated with L-DOPA is co
nfined to small alterations in restricted brain regions. (C) 2001 Elsevier
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