Lack of dopamine receptor agonists effect on striatal dopamine transporter binding sites

Little, Karley Y.; Gorebig, Jenifer; Carroll, F; Mapili, J.; Meador‐Woodruff, James H.

doi:10.1016/s0006-8993(96)01033-5

Cited by 13 publications

(10 citation statements)

References 7 publications

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“…However, the actual density of sites on the DA terminals was not reduced 24 h after pramipexole treatment in WT mice (or in D 3 receptor KO mice), as determined by DAT autoradiography. The inability to modulate the number of DAT binding sites 12 h after termination of subchronic treatment with D 2 /D 3 receptor agonists has previously been reported [44], suggesting that the initial alteration of V max and K m with pramipexole might be due to modification of the kinetics of DAT. However, pramipexole treatment reduced DAT-IR of DA fibers 7 days post-treatment, suggesting a reduction in DAT sites.…”

Section: Discussionmentioning

confidence: 93%

Low dose pramipexole is neuroprotective in the MPTP mouse model of Parkinson's disease, and downregulates the dopamine transporter via the D3 receptor

et al. 2004

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Background: Our aim was to determine if pramipexole, a D 3 preferring agonist, effectively reduced dopamine neuron and fiber loss in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model when given at intraperitoneal doses corresponding to clinical doses. We also determined whether subchronic treatment with pramipexole regulates dopamine transporter function, thereby reducing intracellular transport of the active metabolite of MPTP, 1-methyl-4-phenylpyridinium (MPP+).

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Section: Discussionmentioning

confidence: 93%

Low dose pramipexole is neuroprotective in the MPTP mouse model of Parkinson's disease, and downregulates the dopamine transporter via the D3 receptor

et al. 2004

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“…Likewise, D 2 receptor agonists were indicated not to have any influence on binding of radioligands to the dopamine transporter (Dresel et al, 1988;Vander Borght et al, 1995;Little et al, 1996;Ahlskog et al, 1999 …”

Section: Resultsmentioning

confidence: 99%

[ 123 I]FP-CIT SPECT is a useful method to monitor the rate of dopaminergic degeneration in early-stage Parkinson's disease

Winogrodzka

Bergmans

Booij

et al. 2001

Journal of Neural Transmission

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Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Summary. We investigated the applicability [ 123 I]FP-CIT SPECT for the assessment of the rate of dopaminergic degeneration in PD.Twenty early-stage PD patients (age range 43-73 yr; mean age 55.4) were examined twice, a mean of 12 months apart. The mean annual change in the ratio of specific to nonspecific [ In order to demonstrate a significant effect (p Ͻ 0.05) of putative neuroprotective agent with 0.80 power and 50% of predicted protection within 2 years, 36 patients are required in each group, when the effects are measured by means of changes in [123 I]FP-CIT binding ratios in whole striatum. Our findings indicate that [123 I]FP-CIT SPECT seems to be a useful tool to investigate the progression of dopaminergic degeneration in PD and may provide an objective method of measuring the effectiveness of neuroprotective therapies.

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“…This finding confirms the results of previous animal experiments investigating the influence of several dopamine receptor agonists on the striatal dopamine transporter. [13][14][15] Thus measurement of dopaminergic degeneration in the present study was based on the assumption that treatment with D 2 agonists or levodopa has no significant influence on [ 123 I]β-CIT binding to dopamine transporters. Nonetheless, all of these studies-including the present one-are limited by small sample sizes (and consequently by limited power), as well as by short duration, and therefore do not exclude the possibility that pharmacological effects could emerge in larger or longer term studies.…”

Section: Discussionmentioning

confidence: 99%

“…12 Likewise, D 2 receptor agonists appear to have no influence on the expression of the striatal dopamine transporter. [13][14][15] However, the effects of these drugs on striatal [ 123 I]β-CIT binding in Parkinson's disease have only been examined in one study. 28 Effect of D 2 receptor agonist on striatal [ 123 I]β-CIT binding…”

Section: Drug Treatmentmentioning

confidence: 99%

[123I]beta-CIT SPECT is a useful method for monitoring dopaminergic degeneration in early stage Parkinson's disease

Winogrodzka

2003

Journal of Neurology, Neurosurgery &Amp; Psychiatry

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123 I]β-CIT binding ratios was about 8% in the whole striatum, 8% in the putaminal region, and 4% in the caudate region. Comparison of scans done in nine patients under two different conditions-in the off state and while on drug treatment-showed no significant alterations in the expression of striatal dopamine transporters as measured using [123 I]β-CIT SPECT. Power analysis indicated that to detect a significant (p < 0.05) effect of a neuroprotective agent with 0.80 power and 30% of predicted protection within two years, 216 patients are required in each group when the effects are measured in the whole putamen.

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Lack of dopamine receptor agonists effect on striatal dopamine transporter binding sites

Cited by 13 publications

References 7 publications

Low dose pramipexole is neuroprotective in the MPTP mouse model of Parkinson's disease, and downregulates the dopamine transporter via the D3 receptor

Low dose pramipexole is neuroprotective in the MPTP mouse model of Parkinson's disease, and downregulates the dopamine transporter via the D3 receptor

[ 123 I]FP-CIT SPECT is a useful method to monitor the rate of dopaminergic degeneration in early-stage Parkinson's disease

[123I]beta-CIT SPECT is a useful method for monitoring dopaminergic degeneration in early stage Parkinson's disease

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