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@ARTICLE{Depboylu:137775,
author = {Depboylu, Candan and Maurer, Lukas and Matusch, Andreas and
Hermanns, Guido and Windolph, Andrea and Béhé, Martin and
Oertel, Wolfgang H. and Höglinger, Günter U.},
title = {{E}ffect of long-term treatment with pramipexole or
levodopa on presynaptic markers assessed by longitudinal
[123{I}]{FP}-{CIT} {SPECT} and histochemistry},
journal = {NeuroImage},
volume = {79},
issn = {1053-8119},
address = {Orlando, Fla.},
publisher = {Academic Press},
reportid = {FZJ-2013-04091},
pages = {191 - 200},
year = {2013},
abstract = {A previous clinical trial studied the effect of long-term
treatment with levodopa (LD) or the dopamine agonist
pramipexole (PPX) on disease progression in Parkinson
disease using SPECT with the dopamine transporter
(DAT)-radioligand [(123)I]β-CIT as surrogate marker.
[(123)I]β-CIT binding declined to significantly lower
levels in patients receiving LD compared to PPX. However,
the interpretation of this difference as LD-induced
neurotoxicity, PPX-induced neuroprotection/-regeneration, or
only drug-induced regulatory changes of DAT-availability
remained controversial. To address this question
experimentally, we induced a subtotal lesion of the
substantia nigra in mice by bilateral injection of the
neurotoxin 6-hydroxydopamine. After 4 weeks, mice were
treated for 20 weeks orally with LD (100mg/kg/day) or PPX
(3mg/kg/day), or water (vehicle) only. The integrity of
nigrostriatal projections was assessed by repeated
[(123)I]FP-CIT SPECT in vivo and by immunostaining for DAT
and the dopamine-synthesizing enzyme tyrosine hydroxylase
(TH) after sacrifice. In sham-lesioned mice, we found that
both LD and PPX treatment significantly decreased the
striatal FP-CIT binding (LD: $-21\%;$ PPX: $-14\%)$ and
TH-immunoreactivity (LD: $-42\%;$ PPX: $-45\%),$ but
increased DAT-immunoreactivity (LD: $+42\%;$ PPX: $+33\%)$
compared to controls without dopaminergic treatment. In
6-hydroxydopamine-lesioned mice, however, neither LD nor PPX
significantly influenced the stably reduced FP-CIT SPECT
signal (LD: $-66\%;$ PPX: $-66\%;$ controls $-66\%),$
TH-immunoreactivity (LD: $-70\%;$ PPX: $-72\%;$ controls:
$-77\%)$ and DAT-immunoreactivity (LD: $-70\%;$ PPX:
$-75\%;$ controls: $-75\%)$ in the striatum or the number of
TH-positive cells in the substantia nigra (LD: $-88\%;$ PPX:
$-88\%;$ controls: $-86\%),$ compared to lesioned mice
without dopaminergic treatment. In conclusion, chronic
dopaminergic stimulation with LD or PPX induced similar
adaptive presynaptic changes in healthy mice, but no
discernible changes in severely lesioned mice. These
findings allow to more reliably interpret the results from
clinical trials using neuroimaging of DAT as surrogate
parameter. Copyright © 2013 Elsevier Inc. All rights
reserved.},
cin = {INM-2},
ddc = {610},
cid = {I:(DE-Juel1)INM-2-20090406},
pnm = {333 - Pathophysiological Mechanisms of Neurological and
Psychiatric Diseases (POF2-333)},
pid = {G:(DE-HGF)POF2-333},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000320412200020},
doi = {10.1016/j.neuroimage.2013.04.076},
url = {https://juser.fz-juelich.de/record/137775},
}