Navegando por Palavras-chave "GAP-43"

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    Growth-associated phosphoprotein expression is increased in the supragranular regions of the dentate gyrus following pilocarpine-induced seizures in rats
    (Elsevier B.V., 1999-01-01) Naffah-Mazzacoratti, M. G.; Funke, M. G.; Sanabria, ERG; Cavalheiro, E. A.; Universidade Federal de São Paulo (UNIFESP)
    Neuroplasticity has been investigated considering the neuronal growth-associated phosphoprotein as a marker of neuronal adaptive capabilities. in the present work, studying the hippocampal reorganization observed in the epilepsy model induced by pilocarpine, we carried out quantitative western blotting associated with immunohistochemistry to determine the distribution of growth-associated phosphoprotein in the hippocampus of rats in acute, silent and chronic periods of this epilepsy model. the fibers and punctate elements from the inner molecular layer of the dentate gyrus were strongly immunostained in animals killed 5 h after status epilepticus, compared with the same region in control animals. Rats presenting partial seizures showed no alterations in the immunostaining pattern compared with saline-treated animals. the hippocampal dentate gyrus of animals during the seizure-free period and presenting spontaneous recurrent seizures was also characterized by strong growth-associated phosphoprotein immunostaining of fibers and punctate elements in the inner molecular layer, contrasting with the control group. As determined by western blotting analysis, growth-associated phosphoprotein levels increased following status epilepticus and remained elevated at the later time-points, both during the silent period and during the period of chronic recurring seizures. Pilocarpine-treated animals, which did not develop status epilepticus, showed no change in growth-associated phosphoprotein levels, indicating that status epilepticus is important to induce growth-associated phosphoprotein overexpression.The measurement of this overexpression could represent one of the early signals of hippocampal reorganization due to status epilepticus-induced damage. (C) 1999 IBRO. Published by Elsevier B.V.
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    Growth-associated protein 43 expression in hippocampal molecular layer of chronic epileptic rats treated with cycloheximide
    (Wiley-Blackwell, 2005-01-01) Longo, Beatriz Monteiro [UNIFESP]; Vezzani, Annamaria; Mello, Luiz Eugenio Araujo de Moraes [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Mario Negri Inst Pharmacol Res; Fiocruz MS
    Purpose: GAP43 has been thought to be linked with mossy fiber sprouting (MFS) in various experimental models of epilepsy. To investigate how GAP43 expression (GAP43-ir) correlates with MFS, we assessed the intensity (densitometry) and extension (width) of GAP43-ir in the inner molecular layer of the dentate gyrus (IML) of rats subject to status epilepticus induced by pilocarpine (Pilo), previously injected or not with cycloheximide (CHX), which has been shown to inhibit MFS.Methods: CHX was injected before the Pilo injection in adult Wistar rats. The Pilo group was injected with the same drugs, except for CHX. Animals were killed between 30 and 60 days later, and brain sections were processed for GAP43 immunohistochemistry.Results: Densitometry showed no significant difference regarding GAP43-ir in the IML between Pilo, CHX+Pilo, and control groups. However, the results of the width of the GAP43-ir band in the IML showed that CHX+Pilo and control animals had a significantly larger band (p = 0.03) as compared with that in the Pilo group.Conclusions: Our current finding that animals in the CHX+Pilo group have a GAP43-ir band in the IML, similar to that of controls, reinforces prior data on the blockade of MFS in these animals. The change in GAP43-ir present in Pilo-treated animals was a thinning of the band to a very narrow layer just above the granule cell layer that is likely to be associated with the loss of hilar cell projections that express GAP-43.
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    Neuromodulatory property of standardized extract Ginkgo biloba L. (EGb 761) on memory: Behavioral and molecular evidence
    (Elsevier B.V., 2009-05-07) Oliveira, Daniela R. [UNIFESP]; Sanada, Priscila F. [UNIFESP]; Saragossa Filho, A. C. [UNIFESP]; Innocenti, L. R.; Oler, Gisele [UNIFESP]; Cerutti, Janete M. [UNIFESP]; Cerutti, Suzete M. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Univ Sao Francisco
    Although it has been suggested that the standardized Ginkgo biloba leaf extract (Egb 761) may have a beneficial effect on memory, the cellular and molecular changes that underlie this process are not yet well defined. the present study evaluated the effects of acute (one dose) or subacute treatments (one daily dose/seven days) with EGb 761 (0.5 g kg(-1) and 1.0 g kg(-1)) on rats submitted to a conditioned emotional response (CER) in comparison with positive (4 mg kg(-1) Diazepam) and negative (12% Tween 80) control groups. To this end, eighty (n = 10/group) adult, male, Wistar rats (+/- 250-300 g) were used in an off-baseline CER procedure. We here observed that the rats submitted to an acute and subacute EGb 761 treatments had acquisition of fear conditioning. Additionally, we investigate if the expression of genes previously associated with classical conditioning (CREB-1 and GAP-43) and new candidate genes (GFAP) are modulated following EGb 761 acute treatment. CREB-1, GAP-43 and GFAP mRNA and protein expressions were evaluated using both quantitative PCR (qPCR) and immunohistochemical analysis, respectively. We here show, for the first time, that EGb 761 modulated GAP-43, CREB-1 and GFAP expression in the prefrontal cortex, amygdala and hippocampus. We observed an underexpression of GAP-43 in all structures evaluated and over-expression of GFAP in the amygdala and hippocampus following acute G. biloba treatment when compared to control group (Tween; p<0.01). GAP-43 expression was decreased in prefrontal cortex and hippocampus in the subacute treatment with EGb 761. Subacute treatment with EGb 761 lead to a decreased CREB-1 in mPFC (p<0.001) and increased in the hippocampus to 1.0 g kg(-1) G. biloba group (p<0.001). the results obtained from immunohistochemical analysis support our aforementioned findings and revealed that the changes in expression occurred within specific regions in the areas evaluated. All together, our findings not only provide new evidence for a role of EGb 761 on memory but also identify molecular changes that underlie the fear memory consolidation. (C) 2008 Elsevier B.V. All rights reserved.
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    The role of mossy cell death and activation of protein synthesis in the sprouting of dentate mossy fibers: Evidence from calretinin and neo-timm staining in pilocarpine-epileptic mice
    (Lippincott Williams & Wilkins, 2000-01-01) Silva, Julieta Gonçalves [UNIFESP]; Mello, Luiz Eugenio Araujo de Moraes [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Mossy fiber sprouting is a major anatomical reorganization seen in patients with temporal lobe epilepsy and animal models of epilepsy. the final outcome of this reorganization is viewed by many as epileptogenic. Yet, important and relevant data from both human and animal models of epilepsy challenge this prevailing view. Regardless of the outcome of this debate, understanding of the mechanisms that underlie massy fiber sprouting (MFS) might contribute to our understanding of both the adaptive and maladaptive changes that take place in the nervous system after injury. Available evidence suggests that two events might be crucial for mossy fibers to sprout in epilepsy: the death of mossy cells and the synthesis of trophic factors. the availability of means that prevent MFS, which is normally triggered after induction of status epilepticus, allow for the testing of hypotheses regarding the need for and the sufficiency of specific events for mossy fibers to sprout. We present data on a specific marker for mossy cells, calretinin, in the pilocarpine model of epilepsy in mice. Our data suggest that in the presence of a protein synthesis inhibitor status epilepticus-induced death of mossy cells is not sufficient to trigger mossy fiber sprouting. We suggest that both events, mossy cell death and synthesis of trophic factors, might be necessary for robust MFS to ensue.