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Rui Gao, Guangjian Zhang, Xueqi Chen, Aimin Yang, Gwenn Smith, Dean F Wong, Yun Zhou
OBJECTIVE: Cerebrospinal fluid (CSF) biomarkers, such as α-synuclein (α-syn), amyloid beta peptide 1-42 (Aβ1-42), phosphorylated tau (181P) (p-tau), and total tau (t-tau), have long been associated with the development of Parkinson disease (PD) and other neurodegenerative diseases. In this investigation, we reported the assessment of CSF biomarkers and their correlations with vesicular monoamine transporter 2 (VMAT2) bindings measured with 18F-9-fluoropropyl-(+)-dihydrotetrabenazine (18F-AV133) that is being developed as a biomarker for PD...
2016: PloS One
Kai-Cheng Hsu, Feng-Sheng Wang
Model-based optimization approaches are valuable in developing new drugs for human metabolic disorders. The core objective in most optimal drug designs is positive therapeutic effects. In this study, we considered the effects of therapeutic, adverse, and target variation simultaneously. A fuzzy optimization method was applied to formulate a multiobjective drug design problem for detecting enzyme targets in the presynaptic dopamine metabolic network to remedy two types of enzymopathies caused by deficiencies of vesicular monoamine transporter 2 (VMAT2) and tyrosine hydroxylase (TH)...
2016: PloS One
Andres Asser, Sulev Kõks, Anniina Snellman, Merja Haaparanta-Solin, Eveliina Arponen, Tove Grönroos, Jaak Nairismägi, Jonas Bergquist, Ursel Soomets, Piret Piip, Mall Eltermaa, Martin Sauk, Hanna Lindmäe, Juha O Rinne, Pille Taba
Intravenous use of a psychostimulant drug containing methcathinone (ephedrone) and manganese causes an irreversible extrapyramidal syndrome in drug abusers. We aimed to reproduce the syndrome in mice to evaluate dopaminergic damage. C57/B6 mice were intraperitoneally injected once a day with the study drug or saline for a period of 27 weeks. Motor activity was recorded in an automated motility-box. After 13 and 27 weeks of treatment, ex vivo digital autoradiography was performed using [11C]dihydrotetrabenazine ([11C]DTBZ)...
September 27, 2016: Brain Research
Mika Naganawa, Shu-Fei Lin, Keunpoong Lim, David Labaree, Jim Ropchan, Paul Harris, Yiyun Huang, Masanori Ichise, Richard E Carson, Gary W Cline
INTRODUCTION: (18)F-Fluoropropyl-(+)-dihydrotetrabenazine ((18)F-FP-(+)-DTBZ) is a vesicular monoamine transporter type 2 (VMAT2) radiotracer for positron emission tomography (PET) imaging to quantify human β-cell mass. Renal cortex and spleen have been suggested as reference regions, however, little is known about (18)F-FP-(+)-DTBZ binding in these regions including the fraction of radiometabolite. We compared the kinetics of (18)F-FP-(+)-DTBZ and its inactive enantiomer (18)F-FP-(-)-DTBZ in baboons, estimated the non-displaceable binding (VND) of the tracers, and used ex vivo studies to measure radiometabolite fractions...
September 2, 2016: Nuclear Medicine and Biology
Zih-Rou Huang, Chia-Ling Tsai, Ya-Yao Huang, Chyng-Yann Shiue, Kai-Yuan Tzen, Ruoh-Fang Yen, Ling-Wei Hsin
In the early 1990s, 9-(+)-11C-dihydrotetrabenazine (9-(+)-11C-DTBZ) was shown to be a useful positron emission tomography (PET) imaging agent for various neurodegenerative disorders. Here, we described the radiosynthesis and evaluation of the 9-(+)-11C-DTBZ analog, 10-(+)-11C-DTBZ, as a vesicular monoamine transporter 2 (VMAT2) imaging agent and compare it with 9-(+)-11C-DTBZ. 10-(+)-11C-DTBZ was obtained by 11C-MeI methylation with its 10 hydroxy precursor in the presence of 5 M NaOH. It had a slightly better average radiochemical yield of 35...
2016: PloS One
Alessandra Bacca, Angela Pucci, Daniele Lorenzini, Serena Chiacchio, Duccio Volterrani, Mauro Ferrari, Stefano Sellari Franceschini, Gabriele Materazzi, Fulvio Basolo, Giampaolo Bernini
BACKGROUND: The expression of vesicular catecholamine transporters (VMAT1 and 2) in pheochromocytomas (PHEOs) and paragangliomas (PGLs) and the possible relationships with [18F]FDOPA PET/CT and [123I]MIBG scintigraphy uptake are unknown. Our purpose was to investigate possible correlations of either VMAT1 and VMAT2 expression with the functional imaging in patients with PHEOs and PGLs. METHODS: An observational 3-year time study was performed by enrolling 31 consecutive patients with PHEO (n=17) or PGL (n= 14)...
September 2, 2016: Quarterly Journal of Nuclear Medicine and Molecular Imaging
Patricia Ortega-Sáenz, David Macías, Konstantin L Levitsky, José A Rodríguez-Gómez, Patricia González-Rodríguez, Victoria Bonilla-Henao, Ignacio Arias-Mayenco, José López-Barneo
KEY POINTS: Biotin, a vitamin whose main role is as a coenzyme for carboxylases, accumulates at unusually large amounts within cells of the carotid body (CB). In biotin-deficient rats biotin rapidly disappears from the blood; however, it remains at relatively high levels in CB glomus cells. The CB contains high levels of mRNA for SLC5a6, a biotin transporter, and SLC19a3, a thiamine transporter regulated by biotin. Animals with biotin deficiency exhibit pronounced metabolic lactic acidosis...
August 28, 2016: Journal of Physiology
Justin R Nickell, John P Culver, Venumadhav Janganati, Guangrong Zheng, Linda P Dwoskin, Peter A Crooks
A small library of 1,4-diphenethylpiperazine analogs was synthesized and evaluated for inhibition of [(3)H]dihydrotetrabenazine binding and [(3)H]dopamine uptake at the vesicular monoamine transporter-2 (VMAT2). Results from these studies identified three novel molecules, 6b, 6e and 9a (Ki=35nM, 48nM and 37nM, respectively) that exhibit similar potency for inhibition of VMAT2 function compared with lobelane (Ki=45nM), and importantly, have enhanced water-solubility when compared to the previously reported 1,4-diphenethylpiperidine analogs...
September 15, 2016: Bioorganic & Medicinal Chemistry Letters
Kelly M Lohr, Shababa T Masoud, Ali Salahpour, Gary W Miller
Dopamine was first identified as a neurotransmitter localized to the midbrain over 50 years ago. The dopamine transporter (DAT; SLC6A3) and the vesicular monoamine transporter 2 (VMAT2; SLC18A2) are two regulators of dopamine homeostasis in the presynaptic neuron. DAT transports dopamine from the extracellular space into the cytosol of the presynaptic terminal. VMAT2 then packages this cytosolic dopamine into vesicular compartments for subsequent release upon neurotransmission. Thus, DAT and VMAT2 act in concert to move transmitter efficiently throughout the neuron...
August 13, 2016: European Journal of Neuroscience
Lu Gao, Wenbo Zhou, Breanna Symmes, Curt R Freed
Parkinson's disease is characterized by the death of dopaminergic neurons in the substantia nigra. To understand the molecular mechanisms of the disease, an in vitro model is important. In the 1990s, we used the SV40 large T antigen to immortalize dopaminergic neurons derived from Embryonic Day 14 rat mesencephalon. We selected a clone for its high expression of dopaminergic neuron markers such as tyrosine hydroxylase (TH), and we named it 1RB3AN27 (N27). Because the original N27 cell line has been passaged many times, the line has become a mixture of cell types with highly variable expression of TH...
2016: PloS One
Bojana Stefanovic, Natasa Spasojevic, Predrag Jovanovic, Nebojsa Jasnic, Jelena Djordjevic, Sladjana Dronjak
The hippocampus is sensitive to stress which activates norepinephrine terminals deriving from the locus coeruleus. Melatonin exerts positive effects on the hippocampal neurogenic process and on depressive-like behaviour. Thus, in the present study, an examination was made of the effect of chronic melatonin treatment on norepinephrine content, synthesis, uptake, vesicular transport and degradation in the hippocampus of rats exposed to CUMS. This entailed quantifying the norephinephrine, mRNA and protein levels of DBH, NET, VMAT 2, MAO-A and COMT...
October 2016: European Neuropsychopharmacology: the Journal of the European College of Neuropsychopharmacology
Chen-Cheng Lin, Che-Se Tung, Pin-Hsuan Lin, Chuen-Lin Huang, Yia-Ping Liu
Central catecholamines regulate fear memory across the medial prefrontal cortex (mPFC), amygdala (AMYG), and hippocampus (HPC). However, inadequate evidence exists to address the relationships among these fear circuit areas in terms of the fear symptoms of posttraumatic stress disorder (PTSD). By examining the behavioral profile in a Pavlovian fear conditioning paradigm together with tissue/efflux levels of dopamine (DA) and norepinephrine (NE) and their reuptake abilities across the fear circuit areas in rats that experienced single prolonged stress (SPS, a rodent model of PTSD), we demonstrated that SPS-impaired extinction retrieval was concomitant with the changes of central DA/NE in a dissociable manner...
September 2016: European Neuropsychopharmacology: the Journal of the European College of Neuropsychopharmacology
Renata A N Pertile, Xiaoying Cui, Darryl W Eyles
Vitamin D regulates multiple factors including those involved in the ontogeny of dopaminergic systems. It has been shown that in neonatal rats maternally deprived of vitamin D, dopamine (DA) turnover is decreased with associated reductions in one catabolic enzyme, catechol-o-methyl transferase (COMT). To directly examine this signaling relationship, in the present study we have over-expressed the vitamin D receptor (VDR) in neuroblastoma SH-SY5Y cells in order to examine the mechanisms by which the active vitamin D hormone, 1,25(OH)2D3, via its receptor VDR, affects DA production and turnover...
October 1, 2016: Neuroscience
Leonardo A Parra, Tracy B Baust, Amanda D Smith, Juliann D Jaumotte, Michael J Zigmond, Soledad Torres, Rehana K Leak, Jose A Pino, Gonzalo E Torres
We previously reported that the vesicular monoamine transporter 2 (VMAT2) is physically and functionally coupled with Hsc70 as well as with the dopamine synthesis enzymes tyrosine hydroxylase (TH) and aromatic amino acid decarboxylase, providing a novel mechanism for dopamine homeostasis regulation. Here we expand those findings to demonstrate that Hsc70 physically and functionally interacts with TH to regulate the enzyme activity and synaptic vesicle targeting. Co-immunoprecipitation assays performed in brain tissue and heterologous cells demonstrated that Hsc70 interacts with TH and aromatic amino acid decarboxylase...
August 19, 2016: Journal of Biological Chemistry
Hsiao-Huei Wu, Sera Choi, Pat Levitt
INTRODUCTION: Serotonin (5-HT) is an important neuromodulator, but recently has been shown to be involved in neurodevelopment. Although previous studies have demonstrated that the placenta is a major source of forebrain 5-HT during early forebrain development, the processes of how 5-HT production, metabolism, and transport from placenta to fetus are regulated are unknown. As an initial step in determining the mechanisms involved, we investigated the expression patterns of genes critical for 5-HT system function in mouse extraembryonic tissues...
June 2016: Placenta
Justin R Nickell, John P Culver, Venumadhav Janganati, Guangrong Zheng, Linda P Dwoskin, Peter A Crooks
A series of 1,4-diphenalkylpiperidine analogs were synthesized and evaluated for their affinity and inhibitory potency at the [(3)H]dihydrotetrabenazine (DTBZ) binding site and [(3)H]dopamine (DA) uptake site on the vesicular monoamine transporter-2 (VMAT2). Results revealed that translocation of the phenethyl side chains of lobelane from C2 and C6 to C1 and C4 around the central piperidine ring slightly reduces affinity and inhibitory potency at VMAT2 with respect to lobelane. However, methoxy and fluoro-substitution of either phenyl ring of these 1,4-diphenethyl analogs afforded VMAT2 inhibition comparable or higher (5-fold) affinity at the DTBZ binding and DA uptake sites relative to lobelane, whereas replacement of the 4-phenethyl moiety in these analogs with a 4-phenmethyl moiety markedly reduced affinity for the DTBZ binding and DA uptake sites by 3- and 5-fold, respectively...
July 1, 2016: Bioorganic & Medicinal Chemistry Letters
Reidar Fossmark, Oriol Calvete, Patricia Mjønes, Javier Benitez, Helge L Waldum
A family with a missense variant of the ATP4A gene encoding the alpha subunit of the gastric proton pump (H(+) K(+) ATPase) has recently been described. Homozygous siblings were hypergastrinemic (median gastrin 486 pM) and had gastric tumours diagnosed at a median age of 33 years. In the current histopathological study, we further characterized the tumours found in the gastric corpus. The tumours had the histological appearance of carcinoids (NET G1 or G2) and were immunoreactive for the general neuroendocrine markers chromogranin A (CgA) and synaptophysin as well as the ECL-cell markers vesicular monoamine transporter 2 (VMAT2) and histidine decarbozylase (HDC)...
July 2016: APMIS: Acta Pathologica, Microbiologica, et Immunologica Scandinavica
Aurore N Voisin, Ouissame Mnie-Filali, Nicolas Giguère, Guillaume M Fortin, Erika Vigneault, Salah El Mestikawy, Laurent Descarries, Louis-Éric Trudeau
A subset of monoamine neurons releases glutamate as a cotransmitter due to presence of the vesicular glutamate transporters VGLUT2 or VGLUT3. In addition to mediating vesicular loading of glutamate, it has been proposed that VGLUT3 enhances serotonin (5-HT) vesicular loading by the vesicular monoamine transporter (VMAT2) in 5-HT neurons. In dopamine (DA) neurons, glutamate appears to be released from specialized subsets of terminals and it may play a developmental role, promoting neuronal growth and survival...
2016: Frontiers in Neuroanatomy
HongNa Yang, Jing Wang, Feng Wang, XiaoDun Liu, Heng Chen, WeiMing Duan, TingYu Qu
Transplantation of dopaminergic (DA) neurons is considered to be the most promising therapeutic strategy for replacing degenerated dopamine cells in the midbrain of Parkinson's disease (PD), thereby restoring normal neural circuit function and slow clinical progression of the disease. Human neural stem cells (hNSCs) derived from fetal forebrain are thought to be the important cell sources for producing DA neurons because of their multipotency for differentiation and long-term expansion property in cultures...
2016: Frontiers in Neural Circuits
Nian Xiong, Nuomin Li, Eden Martin, Jinlong Yu, Jie Li, Jing Liu, David Yue-Wei Lee, Ole Isacson, Jeffery Vance, Hong Qing, Tao Wang, Zhicheng Lin
Vesicular monoamine transporter 2 (VMAT2) is responsible for sequestering cytosolically toxic dopamine into intracellular secretory vesicles. Animal genetic studies have suggested that reduced VMAT2 activity contributes to the genetic etiology of Parkinson's disease (PD), but this role has not been established in humans. Based on human genetic association and meta-analysis, we first confirm the human VMAT2 (hVMAT2 or SLC18A2) promoter as a risk factor for PD in both family and unrelated US white people: marker rs363324 at -11...
July 2016: Neurotherapeutics: the Journal of the American Society for Experimental NeuroTherapeutics
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