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- Berglöf, Elisabet, et al.
(författare)
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Locus coeruleus promotes survival of dopamine neurons in ventral mesencephalon : An in oculo grafting study
- 2009
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Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886 .- 1090-2430. ; 216:1, s. 158-165
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Tidskriftsartikel (refereegranskat)abstract
- Parkinson's disease is a neurodegenerative disorder where dopamine neurons in the substantia nigra of ventral mesencephalon undergo degeneration. In addition to the loss of dopamine neurons, noradrenaline neurons in the locus coeruleus degenerate, actually to a higher extent than the dopamine neurons. The interaction between these two nuclei is yet not fully known, hence this study was undertaken to investigate the role of locus coeruleus during development of dopamine neurons utilizing the intraocular grafting model. Fetal ventral mesencephalon and locus coeruleus were implanted either as single grafts or co-grafts, placed in direct contact or at a distance. The results revealed that the direct attachment of locus coeruleus to ventral mesencephalon enhanced graft volume and number of tyrosine hydroxylase (TH)-positive neurons in ventral mesencephalic grafts. Cell counts of subpopulations of TH-positive neurons also immunoreactive for aldehyde dehydrogenase 1-A1 (ALDH1) or calbindin, revealed improved survival of ALDH1/TH-positive neurons. However, the number of calbindin/TH-positive neurons was not affected. High density of dopamine-beta-hydroxylase (DBH)-positive innervation in the ventral mesencephalon placed adjacent to locus coeruleus was correlated to the improved survival. Ventral mesencephalic tissue, implanted at a distance to locus coeruleus, did not demonstrate improved survival, although DBH-positive nerve fibers were detected. In conclusion, the direct contact of locus coeruleus resulting in dense noradrenergic innervation of ventral mesencephalon is beneficial for the survival of ventral mesencephalic grafts. Thus, when trying to rescue dopamine neurons in Parkinson's disease, improving the noradrenergic input to the substantia nigra might be worth considering.
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- Bueters, Tjerk, et al.
(författare)
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Degeneration of newly formed CA1 neurons following global ischemia in the rat
- 2008
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Ingår i: Experimental Neurology. - New York, USA : Academic Press. - 0014-4886 .- 1090-2430. ; 209:1, s. 114-124
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Tidskriftsartikel (refereegranskat)abstract
- The pyramidal neurons of the hippocampal CA1 region are essential for spatial learning and memory and are almost entirely destroyed 7-14 days after transient cerebral ischemia (DAI). Recently, we found that CA1 neurons reappeared at 21-90 DAI, in association with a recovery of ischemia-induced deficits in spatial learning and memory. However, at 125 DAI the number of neurons was fewer than at 90 DAI, suggesting that the new nerve cells undergo neurodegeneration during this time period. We therefore investigated whether neuronal degeneration occurred between 90 and 250 DAI and how this related to learning and memory performance. We found that many of the new CA1 neurons previously seen at 90 DAI had disappeared at 250 DAI. In parallel, large mineralized calcium deposits appeared in the hippocampus and thalamus, in association with neuroinflammatory and astroglial reactions. In spite of the extensive CA1 damage, the ischemic rats showed no deficiencies in spatial learning and memory, as analyzed in the Morris water maze and a complimentary water maze test based on sequential left-right choices. However, ischemia rats showed a general increase in swim length in the Morris water maze suggesting altered search behaviour. Taken together, these results indicate that the CA1 neurons that reappear after transient global ischemia to a large extent degenerate at 125-250 DAI, in parallel with the appearance of a less efficient search strategy.
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- Christophersen, Nicolaj, et al.
(författare)
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Midbrain expression of Delta-like 1 homologue is regulated by GDNF and is associated with dopaminergic differentiation.
- 2007
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Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886. ; 204:2, s. 791-801
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Tidskriftsartikel (refereegranskat)abstract
- Affymetrix GeneChip technology and quantitative real-time PCR (Q-PCR) were used to examine changes in gene expression in the adult murine substantia nigra pars compacta (SNc) following lentiviral glial cell line-derived neurotrophic factor (GDNF) delivery in adult striatum. We identified several genes that were upregulated after GDNF treatment. Among these, the gene encoding the transmembrane protein Delta-like 1 homologue (Dlk1) was upregulated with a greater than 4-fold increase in mRNA encoding this protein. Immunohistochemistry with a Dlk1-specific antibody confirmed the observed upregulation with increased positive staining of cell bodies in the SNc and fibers in the striatum. Analysis of the developmental regulation of Dlk1 in the murine ventral midbrain showed that the upregulation of Dlk1 mRNA correlated with the generation of tyrosine hydroxylase (TH)-positive neurons. Furthermore, Dlk1 expression was analyzed in MesC2.10 cells, which are derived from embryonic human mesencephalon and capable of undergoing differentiation into dopaminergic neurons. We detected upregulation of Dlk1 mRNA and protein under conditions where MesC2.10 cells differentiate into a dopaminergic phenotype (41.7+/-7.1% Dlk1+ cells). In contrast, control cultures subjected to default differentiation into non-dopaminergic neurons only expressed very few (3.7+/-1.3%) Dlk1-immunopositive cells. The expression of Dlk1 in MesC2.10 cells was specifically upregulated by the addition of GDNF. Thus, our data suggest that Dlk1 expression precedes the appearance of TH in mesencephalic cells and that levels of Dlk1 are regulated by GDNF.
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- Collin, Tove, et al.
(författare)
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Quantitative analysis of the generation of different striatal neuronal subtypes in the adult brain following excitotoxic injury.
- 2005
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Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886. ; 195:1, s. 71-80
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Tidskriftsartikel (refereegranskat)abstract
- Recent findings in adult rodents have provided evidence for the formation of new striatal neurons from subventricular zone (SVZ) precursors following stroke. Little is known about which factors determine the magnitude of striatal neurogenesis in the damaged brain. Here we studied striatal neurogenesis following an excitotoxic lesion to the adult rat striatum induced by intrastriatal quinolinic acid (QA) infusion. New cells were labeled with the thymidine-analogue 5-bromo-2'-deoxyuridine (BrdU) and their identity was determined immunocytochemically with various phenotypic markers. The unilateral lesion gave rise to increased cell proliferation mainly in the ipsilateral SVZ. At 2 weeks following the insult, there was a pronounced increase of the number of new neurons co-expressing BrdU and a marker of migrating neuroblasts, doublecortin, in the ipsilateral striatum, particularly its non-damaged medial parts. About 80% of the new neurons survived up to 6 weeks, when they expressed the mature neuronal marker NeuN and were preferentially located in the outer parts of the damaged area. Lesion-generated neurons expressed phenotypic markers of striatal medium spiny neurons (DARPP-32) and intemeurons (parvalbumin or neuropeptide Y). The magnitude of neurogenesis correlated to the size of the striatal damage. Our data show for the first time that an excitotoxic lesion to the striatum can trigger the formation of new striatal neurons with phenotypes of both projection neurons and interneurons.
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| 12. |
- Deierborg, Tomas, et al.
(författare)
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Absence of striatal newborn neurons with mature phenotype following defined striatal and cortical excitotoxic brain injuries.
- 2009
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Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886. ; 219, s. 363-367
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Tidskriftsartikel (refereegranskat)abstract
- Experimental stroke and excitotoxic brain lesion to the striatum or cortex increase the proliferation of cells residing within the ventricular wall and cause subsequent migration of newborn neuroblasts into the lesioned brain parenchyma. In this study, we clarify the different events of neurogenesis following striatal or cortical excitotoxic brain lesions in adult rats. Newborn cells were labeled by intraperitoneal injection of bromo-deoxy-uridine (BrdU), or by green fluorescent protein (GFP)-expressing lentiviral vectors injected into the subventricular zone (SVZ). We show that only neural progenitors born the first 5 days in the SVZ reside and expand within this neurogenic niche over time, and that these early labeled cells are more prone to migrate towards the striatum as neuroblasts. However, these neuroblasts could not mature into NeuN(+) neurons in the striatum. Furthermore, we found that cortical lesions, close or distant from the SVZ, could not upregulate SVZ cell proliferation nor promote neurogenesis. Our study demonstrates that both the time window for labeling proliferating cells and the site of lesion are crucial when assessing neurogenesis following brain injury.
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- Echaniz-Laguna, Andoni, et al.
(författare)
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Muscular mitochondrial function in amyotrophic lateral sclerosis is progressively altered as the disease develops : A temporal study in man
- 2006
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Ingår i: Experimental Neurology. - San Diego, USA : Elsevier. - 0014-4886 .- 1090-2430. ; 198:1, s. 25-30
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Tidskriftsartikel (refereegranskat)abstract
- We performed repeated analysis of mitochondrial respiratory function in skeletal muscle (SM) of patients with early-stage sporadic amyotrophic lateral sclerosis (SALS) to determine whether mitochondrial function was altered as the disease advanced. SM biopsies were obtained from 7 patients with newly diagnosed SALS, the same 7 patients 3 months later, and 7 sedentary controls. Muscle fibers were permeabilized with saponin, then skinned and placed in an oxygraphic chamber to measure basal and maximal adenosine diphosphate (ADP)-stimulated respiration rates and to assess mitochondrial regulation by ADP. We found that the maximal oxidative phosphorylation capacity of muscular mitochondria significantly increased, and muscular mitochondrial respiratory complex IV activity significantly decreased as the disease advanced. This temporal study demonstrates for the first time that mitochondrial function in SM in human SALS is progressively altered as the disease develops.
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- Eriksson, Peter S, 1959
(författare)
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Schizophrenia--a stem cell disorder.
- 2006
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Ingår i: Experimental neurology. - : Elsevier BV. - 0014-4886. ; 199:1, s. 26-7
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Tidskriftsartikel (refereegranskat)
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| 19. |
- Eusebio, Alexandre, et al.
(författare)
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Effects of low-frequency stimulation of the subthalamic nucleus on movement in Parkinson's disease.
- 2008
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Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886 .- 1090-2430. ; 209:1, s. 125-30
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Tidskriftsartikel (refereegranskat)abstract
- Excessive synchronization of basal ganglia neural activity at low frequencies is considered a hallmark of Parkinson's disease (PD). However, few studies have unambiguously linked this activity to movement impairment through direct stimulation of basal ganglia targets at low frequency. Furthermore, these studies have varied in their methodology and findings, so it remains unclear whether stimulation at any or all frequencies < or = 20 Hz impairs movement and if so, whether effects are identical across this broad frequency band. To address these issues, 18 PD patients chronically implanted with deep brain stimulation (DBS) electrodes in both subthalamic nuclei were stimulated bilaterally at 5, 10 and 20 Hz after overnight withdrawal of their medication and the effects of the DBS on a finger tapping task were compared to performance without DBS (0 Hz). Tapping rate decreased at 5 and 20 Hz compared to 0 Hz (by 11.8+/-4.9%, p=0.022 and 7.4+/-2.6%, p=0.009, respectively) on those sides with relatively preserved baseline task performance. Moreover, the coefficient of variation of tap intervals increased at 5 and 10 Hz compared to 0 Hz (by 70.4+/-35.8%, p=0.038 and 81.5+/-48.2%, p=0.043, respectively). These data suggest that the susceptibility of basal ganglia networks to the effects of excessive synchronization may be elevated across a broad low-frequency band in parkinsonian patients, although the nature of the consequent motor impairment may depend on the precise frequencies at which synchronization occurs.
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