scholarly journals Parkinsonism in Phenylketonuria: A Consequence of Dopamine Depletion?

2014 ◽  
pp. 35-38 ◽  
Author(s):  
Marieke Velema ◽  
Erik Boot ◽  
Marc Engelen ◽  
Carla Hollak
Keyword(s):  
Dopamine Depletion

Substantia nigra hyperechogenicity and CSF dopamine depletion in HIV

2008 ◽  
Vol 35 (S 01) ◽  
Author(s):  
J Thiermann ◽  
M Obermann ◽  
M Küper ◽  
O Kastrup ◽  
Ö Yaldizli ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Dopamine Depletion ◽  
Substantia Nigra Hyperechogenicity

Association of the Non-Motor Burden with Patterns of Striatal Dopamine Loss in de novo Parkinson’s Disease

2020 ◽  
Vol 10 (4) ◽  
pp. 1541-1549
Author(s):  
Seok Jong Chung ◽  
Sangwon Lee ◽  
Han Soo Yoo ◽  
Yang Hyun Lee ◽  
Hye Sun Lee ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
De Novo ◽  
Early Stage ◽  
Striatal Dopamine ◽  
Motor Deficits ◽  
Dopamine Depletion ◽  
Severe Motor ◽  
Severe Group ◽  
Striatal Dopamine Depletion

Background: Striatal dopamine deficits play a key role in the pathogenesis of Parkinson’s disease (PD), and several non-motor symptoms (NMSs) have a dopaminergic component. Objective: To investigate the association between early NMS burden and the patterns of striatal dopamine depletion in patients with de novo PD. Methods: We consecutively recruited 255 patients with drug-naïve early-stage PD who underwent 18F-FP-CIT PET scans. The NMS burden of each patient was assessed using the NMS Questionnaire (NMSQuest), and patients were divided into the mild NMS burden (PDNMS-mild) (NMSQuest score <6; n = 91) and severe NMS burden groups (PDNMS-severe) (NMSQuest score >9; n = 90). We compared the striatal dopamine transporter (DAT) activity between the groups. Results: Patients in the PDNMS-severe group had more severe parkinsonian motor signs than those in the PDNMS-mild group, despite comparable DAT activity in the posterior putamen. DAT activity was more severely depleted in the PDNMS-severe group in the caudate and anterior putamen compared to that in the PDMNS-mild group. The inter-sub-regional ratio of the associative/limbic striatum to the sensorimotor striatum was lower in the PDNMS-severe group, although this value itself lacked fair accuracy for distinguishing between the patients with different NMS burdens. Conclusion: This study demonstrated that PD patients with severe NMS burden exhibited severe motor deficits and relatively diffuse dopamine depletion throughout the striatum. These findings suggest that the level of NMS burden could be associated with distinct patterns of striatal dopamine depletion, which could possibly indicate the overall pathological burden in PD.

scholarly journals Neuroprotective Potential of a Small Molecule RET Agonist in Cultured Dopamine Neurons and Hemiparkinsonian Rats

2021 ◽  
pp. 1-24
Author(s):  
Juho-Matti Renko ◽  
Arun Kumar Mahato ◽  
Tanel Visnapuu ◽  
Konsta Valkonen ◽  
Mati Karelson ◽  
...  
Keyword(s):  
Mapk Signaling ◽  
Dopamine Neurons ◽  
Dopamine Depletion ◽  
Wild Type ◽  
Disease Modifying Therapy ◽  
Immortalized Cells ◽  
Midbrain Dopamine ◽  
6 Hydroxydopamine

Background: Parkinson’s disease (PD) is a progressive neurological disorder where loss of dopamine neurons in the substantia nigra and dopamine depletion in the striatum cause characteristic motor symptoms. Currently, no treatment is able to halt the progression of PD. Glial cell line-derived neurotrophic factor (GDNF) rescues degenerating dopamine neurons both in vitro and in animal models of PD. When tested in PD patients, however, the outcomes from intracranial GDNF infusion paradigms have been inconclusive, mainly due to poor pharmacokinetic properties. Objective: We have developed drug-like small molecules, named BT compounds that activate signaling through GDNF’s receptor, the transmembrane receptor tyrosine kinase RET, both in vitro and in vivo and are able to penetrate through the blood-brain barrier. Here we evaluated the properties of BT44, a second generation RET agonist, in immortalized cells, dopamine neurons and rat 6-hydroxydopamine model of PD. Methods: We used biochemical, immunohistochemical and behavioral methods to evaluate the effects of BT44 on dopamine system in vitro and in vivo. Results: BT44 selectively activated RET and intracellular pro-survival AKT and MAPK signaling pathways in immortalized cells. In primary midbrain dopamine neurons cultured in serum-deprived conditions, BT44 promoted the survival of the neurons derived from wild-type, but not from RET knockout mice. BT44 also protected cultured wild-type dopamine neurons from MPP +-induced toxicity. In a rat 6-hydroxydopamine model of PD, BT44 reduced motor imbalance and could have protected dopaminergic fibers in the striatum. Conclusion: BT44 holds potential for further development into a novel, possibly disease-modifying therapy for PD.

Patterns of striatal dopamine depletion in early Parkinson disease

Neurology ◽  
2020 ◽  
Vol 95 (3) ◽  
pp. e280-e290 ◽  
Author(s):  
Seok Jong Chung ◽  
Hye Sun Lee ◽  
Han Soo Yoo ◽  
Yang Hyun Lee ◽  
Phil Hyu Lee ◽  
...  
Keyword(s):  
Factor Analysis ◽  
Parkinson Disease ◽  
Cox Regression ◽  
Early Stage ◽  
Freezing Of Gait ◽  
Striatal Dopamine ◽  
Dopamine Depletion ◽  
Wearing Off ◽  
Striatal Dopamine Depletion ◽  
Selective Dopamine

ObjectiveTo investigate whether the patterns of striatal dopamine depletion on dopamine transporter (DAT) scans could provide information on the long-term prognosis in Parkinson disease (PD).MethodsWe enrolled 205 drug-naive patients with early-stage PD, who underwent 18F-FP-CIT PET scans at initial assessment and received PD medications for 3 or more years. After quantifying the DAT availability in each striatal subregion, factor analysis was conducted to simplify the identification of striatal dopamine depletion patterns and to yield 4 striatal subregion factors. We assessed the effect of these factors on the development of levodopa-induced dyskinesia (LID), wearing-off, freezing of gait (FOG), and dementia during the follow-up period (6.84 ± 1.80 years).ResultsThe 4 factors indicated which striatal subregions were relatively preserved: factor 1 (caudate), factor 2 (more-affected sensorimotor striatum), factor 3 (less-affected sensorimotor striatum), and factor 4 (anterior putamen). Cox regression analyses using the composite scores of these striatal subregion factors as covariates demonstrated that selective dopamine depletion in the sensorimotor striatum was associated with a higher risk for developing LID. Selective dopamine loss in the putamen, particularly in the anterior putamen, was associated with early development of wearing-off. Selective involvement of the anterior putamen was associated with a higher risk for dementia conversion. However, the patterns of striatal dopamine depletion did not affect the risk of FOG.ConclusionsThese findings suggested that the patterns of striatal dopaminergic denervation, which were estimated by the equation derived from the factor analysis, have a prognostic implication in patients with early-stage PD.

scholarly journals In vivo electrophysiology of nigral and thalamic neurons in alpha-synuclein-overexpressing mice highlights differences from toxin-based models of parkinsonism

2013 ◽  
Vol 110 (12) ◽  
pp. 2792-2805 ◽  
Author(s):  
C. J. Lobb ◽  
A. K. Zaheer ◽  
Y. Smith ◽  
D. Jaeger
Keyword(s):  
Primary Motor Cortex ◽  
Alpha Synuclein ◽  
Motor Dysfunction ◽  
Motor Deficits ◽  
Dopamine Depletion ◽  
Wild Type ◽  
Beta Oscillations ◽  
Nigrostriatal Dopamine ◽  
6 Hydroxydopamine

Numerous studies have suggested that alpha-synuclein plays a prominent role in both familial and idiopathic Parkinson's disease (PD). Mice in which human alpha-synuclein is overexpressed (ASO) display progressive motor deficits and many nonmotor features of PD. However, it is unclear what in vivo pathophysiological mechanisms drive these motor deficits. It is also unknown whether previously proposed pathophysiological features (i.e., increased beta oscillations, bursting, and synchronization) described in toxin-based, nigrostriatal dopamine-depletion models are also present in ASO mice. To address these issues, we first confirmed that 5- to 6-mo-old ASO mice have robust motor dysfunction, despite the absence of significant nigrostriatal dopamine degeneration. In the same animals, we then recorded simultaneous single units and local field potentials (LFPs) in the substantia nigra pars reticulata (SNpr), the main basal ganglia output nucleus, and one of its main thalamic targets, the ventromedial nucleus, as well as LFPs in the primary motor cortex in anesthetized ASO mice and their age-matched, wild-type littermates. Neural activity was examined during slow wave activity and desynchronized cortical states, as previously described in 6-hydroxydopamine-lesioned rats. In contrast to toxin-based models, we found a small decrease, rather than an increase, in beta oscillations in the desynchronized state. Similarly, synchronized burst firing of nigral neurons observed in toxin-based models was not observed in ASO mice. Instead, we found more subtle changes in pauses of SNpr firing compared with wild-type control mice. Our results suggest that the pathophysiology underlying motor dysfunction in ASO mice is distinctly different from striatal dopamine-depletion models of parkinsonism.

Poster #20 DOPAMINERGIC MODULATION OF THE REWARD SYSTEM IN SCHIZOPHRENIA: A PLACEBO-CONTROLLED DOPAMINE DEPLETION FMRI STUDY

2012 ◽  
Vol 136 ◽  
pp. S98-S99
Author(s):  
Fabiana da Silva Alves ◽  
Nicole Schmitz ◽  
Nico Abeling ◽  
Johan van der Meer ◽  
Aart Nederveen ◽  
...  
Keyword(s):  
Reward System ◽  
Dopamine Depletion ◽  
Fmri Study ◽  
Dopaminergic Modulation
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