| 1. |
- Fredriksson, K, et al.
(författare)
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Regional cerebral blood flow in conscious stroke-prone spontaneously hypertensive rats
- 1984
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - 1559-7016. ; 4:1, s. 103-106
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Tidskriftsartikel (refereegranskat)abstract
- Regional cerebral blood flow (rCBF) was measured autoradiographically with [14C]iodoantipyrine as a diffusible tracer in two strains of conscious normotensive rats (Wistar Kyoto and local Wistar) and in two groups of spontaneously hypertensive stroke-prone rats (SHRSP) with a mean arterial pressure (MAP) below or above 200 mm Hg. In spite of the large differences in arterial pressure, rCBF did not differ significantly between the hypertensive and the normotensive groups in any of the 14 specified brain structures measured. However, rCBF increased asymmetrically within part of the caudate-putamen in two of nine SHRSP with a MAP above 200 mm Hg, indicating a regional drop in the elevated cerebrovascular resistance.
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| 2. |
- Johansson, Barbro, et al.
(författare)
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Neuronal plasticity and dendritic spines: effect of environmental enrichment on intact and postischemic rat brain.
- 2002
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 1559-7016 .- 0271-678X. ; 22:1, s. 89-96
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Tidskriftsartikel (refereegranskat)abstract
- The authors compared the influence of environmental enrichment on intact and lesioned brain, and tested the hypothesis that postischemic exposure to an enriched environment can alter dendritic spine density in pyramidal neurons contralateral to a cortical infarct. The middle cerebral artery was occluded distal to the striatal branches in spontaneously hypertensive rats postoperatively housed either in a standard or in an enriched environment. Intact rats were housed in the same environment. Three weeks later the brains were perfused in situ. The dendritic and spine morphology was studied with three-dimensional confocal laser scanning microscopy after microinjection of Lucifer yellow in pyramidal neurons in layers II/III and V/VI in the somatosensory cortex. In intact rats, the number of dendritic spines was significantly higher in the enriched group than in the standard group in all layers ( P < 0.05). Contralateral to the infarct, pyramidal neurons in layers II/III, which have extensive intracortical connections that may play a role in cortical plasticity, had significantly more spines in the enriched group than in the standard group ( P < 0.05). No difference was observed in layers V/VI. They conclude that housing rats in an enriched environment significantly increases spine density in superficial cortical layers in intact and lesioned brain, but in deeper layers of intact brain.
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| 3. |
- Johansson, Barbro
(författare)
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Regeneration and plasticity in the brain and spinal cord.
- 2007
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 1559-7016 .- 0271-678X. ; 27:8, s. 1417-1430
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Forskningsöversikt (refereegranskat)abstract
- The concept of brain plasticity covers all the mechanisms involved in the capacity of the brain to adjust and remodel itself in response to environmental requirements, experience, skill acquisition, and new challenges including brain lesions. Advances in neuroimaging and neurophysiologic techniques have increased our knowledge of task-related changes in cortical representation areas in the intact and injured human brain. The recognition that neuronal progenitor cells proliferate and differentiate in the subventricular zone and dentate gyrus in the adult mammalian brain has raised the hope that regeneration may be possible after brain lesions. Regeneration will require that new cells differentiate, survive, and integrate into existing neural networks and that axons regenerate. To what extent this will be possible is difficult to predict. Current research explores the possibilities to modify endogenous neurogenesis and facilitate axonal regeneration using myelin inhibitory factors. After apoptotic damage in mice new cortical neurons can form long-distance connections. Progenitor cells from the subventricular zone migrate to cortical and subcortical regions after ischemic brain lesions, apparently directed by signals from the damaged region. Postmortem studies on human brains suggest that neurogenesis may be altered in degenerative diseases. Functional and anatomic data indicate that myelin inhibitory factors, cell implantation, and modification of extracellular matrix may be beneficial after spinal cord lesions. Neurophysiologic data demonstrating that new connections are functioning are needed to prove regeneration. Even if not achieving the goal, methods aimed at regeneration can be beneficial by enhancing plasticity in intact brain regions.
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| 4. |
- Komitova, M, et al.
(författare)
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Effects of cortical ischemia and postischemic environmental enrichment on hippocampal cell genesis and differentiation in the adult rat
- 2002
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 1559-7016 .- 0271-678X. ; 22:7, s. 852-860
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Tidskriftsartikel (refereegranskat)abstract
- The study aimed to elucidate the effects of cortical ischemia and postischemic environmental enrichment on hippocampal cell genesis. A cortical infarct was induced by it permanent ligation of the middle cerebral artery distal to the striatal branches in 6-month-old spontaneously hypertensive rats. Bromodeoxyuridine (BrdU) was administered as 7 consecutive daily injections starting 24 hours after surgery and animals were housed in standard or enriched environment. Four weeks after completed BrdU administration, BrdU incorporation and its co-localization with the neuronal markers NeuN and calbindin D28k, and the astrocytic marker glial fibrillary acidic protein in the granular cell layer and sub,granular zone of the hippocampal dentate gyrus were determined with immunohistochemistry and were quantified stereologically. Compared with sham-operated rats, rats with cortical infarcts had a five- to sixfold ipsilateral increase in BrdU-labeled cells. About 80% of the new cells were neurons. Differential postischemic housing did not influence significantly the total number Of Surviving BrdU-labeled cells or newborn neurons. However, postischemic environmental enrichment increased the ipsilateral generation of astrocytes normalizing the astrocyte-to-neuron ratio. which was significantly reduced in rats housed in standard environment postischemically.
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| 5. |
- Perfilieva, Ekaterina, et al.
(författare)
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Gender and strain influence on neurogenesis in dentate gyrus of young rats
- 2001
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 1559-7016 .- 0271-678X. ; 21:3, s. 211-217
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Tidskriftsartikel (refereegranskat)abstract
- To investigate whether rat hippocampal neurogenesis varies with strain and gender, the authors examined proliferating progenitor cells and their progeny in young male and female Sprague-Dawley (SD) and spontaneously hypertensive rats (SHR) using the thymidine analog bromodeoxyuridine (BrdU) combined with immunohistochemistry for the neuronal marker Calbindin D28k and glial fibrillary acidic protein. Rats were given 7 consecutive daily BrdU injections and were killed 1 day or 4 weeks later to allow for discrimination between proliferation and cell survival. Stereologic analysis of the numbers of BrdU-immunoreactive cells in the dentate gyrus revealed both a strain difference with significantly higher cell proliferation and net neurogenesis in SHR than in SD and a gender difference with males from both strains producing significantly more cells than their female counterparts. Whereas the number of progenitors four weeks after BrdU injections was still significantly greater in male than in female SHRs, resulting in a greater net neurogenesis in the male, the number of BrdU-immunoreactive cells did not differ between male and female SD rats, suggesting a greater survival of newly generated cells in the dentate gyrus in female than in male SD rats. No sex or strain difference was observed in the relative ratio of neurogenesis and gliogenesis.
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