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M Figueiró,
J Ilha,
V M Linck,
A P Herrmann,
P Nardin,
C B Menezes,
M Achaval, C A Gonçalves,
L O Porciúncula,
D S Nunes,
E Elisabetsky
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ABSTRACT: Alzheimer's disease (AD) is expected to affect more than 22 million people worldwide by 2025, causing devastating suffering and enormous costs to families and society. AD is a multifactorial disease, with a complex pathological mosaic. In rodents, AD-like dementia can be induced by cerebral microinjection of Aβ peptide, leading to amyloid deposits, amnesia and various features of neurodegeneration. Marapuama (Ptychopetalum olacoides) is regarded as a "brain tonic" in the Amazon region and shows a nootropic profile in rodents.
Because a specific extract (POEE) of Marapuama was shown to possess promnesic and anti-amnesic properties, the aim of this study was to verify if POEE is also effective against Aβ(1-42)-induced cognitive deficit in mice. Additionally, Aβ deposits (Congo red), GFAP immunoreactivity (immunohistochemistry), and neurodegenerative changes in the hippocampal pyramidal layer (Nissl) were examined as measures of Aβ(1-42)-induced neurodegeneration.
CF1 mice were subjected to the experimental Alzheimer model with the Aβ(1-42) i.c.v. administration. The effects of POEE 800 mg/kg were evaluated over 14 consecutive days of treatment.
The data show that 14 days of oral treatment with POEE (800 mg/kg) was effective in preventing Aβ-induced cognitive impairment, without altering the levels of BDNF and with parallel reductions in Aβ deposits and astrogliosis. CA1 hippocampus loss induced by Aβ(1-42) was also diminished in POEE-treated mice.
This study offers evidence of functional and neuroprotective effects of two weeks treatment with a Ptychopetalum olacoides extract against Aβ peptide-induced neurotoxicity in mice. Given the multifactorial nature of neurodegeneration, the considerable potential for an AChE inhibitor displaying associated neuroprotective properties such as here reported warrants further clinic evaluation.
Phytomedicine: international journal of phytotherapy and phytopharmacology 02/2011; 18(4):327-33. · 2.17 Impact Factor
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ABSTRACT: It has been proposed that animals subjected to chronic stress show a stress response that can be reduced by the intake of highly palatable foods ("comfort foods"). However, a palatable diet, rich in sugar or fat, can also lead to oxidative damage and neuronal injury. So, the aim of this study is to verify, in male and female rats, the effects of exposure to chronic stress during free access to regular chow and to a highly palatable diet, on exploratory and anxiety-like behavior, on oxidative stress and on DNA breaks in two structures of the nervous system, hippocampus and striatum. The results showed stress- and diet-induced DNA breaks and an imbalance in the activity of antioxidants enzymes, such as CAT, GPx and SOD in the both structures. In addition, we observed that female rats appear to have higher susceptibility to the stress effects evaluated, and that access to a palatable diet was able to counteract some behavioral effects of stress. However, this same diet-induced oxidative stress and increased DNA breaks, especially in males. Replication of these results with larger sample sizes would further reinforce these conclusions.
Appetite 03/2010; 55(1):108-16. · 2.59 Impact Factor
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ABSTRACT: The ketogenic diet (KD) is a high-fat, low-protein and low-carbohydrate diet included as medical practice against seizure disorders, particularly in children refractory to conventional anti-epileptic drug treatment. However, the molecular basis of its therapeutic effect remains unclear. Considering the growing evidence for the importance of glial cells for neuronal development, survival and plasticity, we investigated astrocyte protein markers from KD fed rats, in different regions of hippocampus, a brain structure commonly involved in seizure disorders. We found a transitory increment in GFAP in the CA3 hippocampal region, but not in the CA1 or dentate gyrus (DG). This change was not accompanied by changes in S100B content or glutamine synthetase activity. In order to evaluate possible hippocampal involvement we investigated spatial-cognitive behavior using the water-maze task. No changes were observed. This transitory gliosis in CA3 could be related to, or precede, other associated changes proposed to be involved in the attenuation of seizure disorders. These data reinforce the importance of hippocampal astrocytes as cell targets during KD feeding.
Nutritional Neuroscience 09/2005; 8(4):259-64. · 1.56 Impact Factor
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ABSTRACT: S100B, a calcium binding protein physiologically produced and released by astrocytes, has been used as a peripheral marker of brain damage. Here, we investigated the effects of subcutaneous injections of methylmercury chloride (MeHg-5mg/kg), an environmental neurotoxicant, on S100B protein content in cerebrospinal fluid (CSF) of adult rats. In addition, the performance of animals in an open field (number of squares crossing and rearings) was also analyzed in order to obtain a possible link between alteration in S100B protein content in CSF and parameters related to neurological injury. MeHg treatment increased serum mercury and S100B protein levels in the CSF. A decrease in the numbers of crossings and rearings was observed in MeHg-treated animals when compared to control group, which suggests a possible neurological injury. The present data show, for the first time, increased S100B levels in CSF after exposure to a neurotoxic metal. Authors discuss the possibility of astrocytic involvement in MeHg-induced neurotoxicity.
Environmental Toxicology and Pharmacology 02/2005; 19(2):249-53. · 1.47 Impact Factor
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L V C Portela,
A B L Tort,
R Walz,
M Bianchin,
P C Trevisol-Bittencourt,
P R Wille,
R C Cardoso,
M M I Ishida,
A vonWangenheim,
E C Grisard,
M Steindel, C A Gonçalves,
D O Souza
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ABSTRACT: To assess whether serum S100B levels could reflect a glial response in patients with epilepsy secondary to neurocysticercosis (NCC) and with idiopathic epilepsy.
Serum S100B levels were measured using an immunoluminometric assay in 20 patients with focal epilepsy related to chronic NCC (NCC group), and 19 patients with focal epilepsy (EPI group), matched by epidemiological and clinical data. Epileptic patients were compared with 20 healthy controls (CON group) matched by age and sex.
No difference was observed in S100B levels among NCC, EPI and CON groups (P>0.39). Serum S100B levels were not affected by antiepileptic drugs, frequency and type of seizures. Preliminarily, significantly higher levels of S100B were observed in patients with bilateral electroencephalographic (EEG) findings than in patients with unilateral and normal EEG findings (P<0.05).
Serum S100B is normal in patients with focal epilepsy related or not to chronic NCC.
Acta Neurologica Scandinavica 12/2003; 108(6):424-7. · 2.47 Impact Factor
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L. V. C. Portela,
A. B. L. Tort,
R. Walz,
M. Bianchin,
P. C. Trevisol-Bittencourt,
P. R. Wille,
R. C. Cardoso,
M. M. I. Ishida,
A. VonWangenheim,
E. C. Grisard,
M. Steindel, C. A. Gonçalves,
D. O. Souza
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ABSTRACT: Objective – To assess whether serum S100B levels could reflect a glial response in patients with epilepsy secondary to neurocysticercosis (NCC) and with idiopathic epilepsy.Subjects and methods – Serum S100B levels were measured using an immunoluminometric assay in 20 patients with focal epilepsy related to chronic NCC (NCC group), and 19 patients with focal epilepsy (EPI group), matched by epidemiological and clinical data. Epileptic patients were compared with 20 healthy controls (CON group) matched by age and sex.Results – No difference was observed in S100B levels among NCC, EPI and CON groups (P > 0.39). Serum S100B levels were not affected by antiepileptic drugs, frequency and type of seizures. Preliminarily, significantly higher levels of S100B were observed in patients with bilateral electroencephalographic (EEG) findings than in patients with unilateral and normal EEG findings (P < 0.05).Conclusion – Serum S100B is normal in patients with focal epilepsy related or not to chronic NCC.
Acta Neurologica Scandinavica 09/2003; 108(6):424 - 427. · 2.47 Impact Factor
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Ultrasound in Obstetrics and Gynecology 12/2002; 16(6):590 - 592. · 3.01 Impact Factor
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ABSTRACT: S100B protein is a calcium-binding protein mostly derived from glial cells, which exerts trophic or toxic effects on neural cells depending on its concentration. Since serum S100B levels has been tested as a potential marker in neuropsychiatric disorders, and structural abnormalities on glial cells have been recently associated with bipolar disorder patients, we conducted this preliminary study to examine if S100B serum levels are altered during first manic episode. We quantitated S100B in serum of 40 subjects (20 unmedicated patients during manic episode and 20 healthy matched controls). The mean+/-S.D. values for S100B for bipolar subjects were 0.065+/-0.068 microg/l and 0.018+/-0.029 microg/l for healthy controls. Increased levels of S100B in bipolar mania was statistically significant (Wilcoxon signed ranks test, Z=-2.45, P=0.01). These preliminary findings suggest that mania may increase the levels of S100B in serum of bipolar disorder patients, which could be related to adaptative neural mechanisms in bipolar mania.
European Neuropsychopharmacology 07/2002; 12(3):269-72. · 4.05 Impact Factor
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ABSTRACT: Primary astrocyte cultures prepared from neonatal hippocampus, cerebral cortex and cerebellum were morphologically distinct. Cells from hippocampus and cortex were almost entirely protoplasmic, whereas cerebellar astrocytes had many processes; in the absence of serum these differences were accentuated. We compared the immunocontent and secretion of the mitogenic protein S100B in these cultures. Immunocontent was 2.5 times higher in cerebellar astrocytes than in hippocampal or cortical astrocytes. Cells from all three regions secreted S100B under basal conditions, but the secretion rate was higher in cerebellar astrocytes. Secretion depended on protein synthesis and was increased by incubation with forskolin or lysophosphatidic acid in mechanisms which were additive. The stellate morphology induced by forskolin was reversed by lysophosphatidic acid in hippocampal but not in cerebellar cultures, suggesting that S100B secretion was not associated with a process-bearing phenotype of astrocytes.
FEBS Letters 01/2001; 486(3):203-7. · 3.54 Impact Factor
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Ultrasound in Obstetrics and Gynecology 12/2000; 16(6):590-2. · 3.01 Impact Factor
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ABSTRACT: The present protocol details a procedure to permeabilize astrocytes in cultures with digitonin as well as to discuss some data about factors that interfere in permeabilization, particularly divalent cations and nucleotides. Two methods to assess astrocyte permeabilization are described: trypan blue exclusion and ELISA for S100B, a specific protein expressed by these cells. Digitonin-permeabilization of astrocytes has been used to investigate intracellular pools of Ca(2+), internal stores of metabolites, phosphoinositide hydrolysis, and recently we standardized a procedure to study protein phosphorylation (Brain Res. 853 (2000) 32-40). A short incubation time (10 min) with 30 microM digitonin permeabilized at least 75% of cells. A range of media with different ionic nature can be used in cell permeabilization without affecting significantly the extent of permeabilization, but calcium and ATP of the order of 10(-5) M induced a partial resealing which deserves to be considered in assays of permeabilized preparations of astrocytes.
Brain Research Protocols 12/2000; 6(1-2):86-90. · 1.82 Impact Factor
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ABSTRACT: A number of approaches can be used to determine the protein kinases and protein phosphatases acting on particular phosphoproteins in vivo. Cell permeabilization represents one such approach. In this overview we discuss the different permeabilization procedures used in bovine adrenal chromaffin cells and in particular the use of digitonin. The effect of various factors on the extent of digitonin-permeabilization, protein phosphorylation and catecholamine release are also discussed. The factors include the permeabilization medium, the ions such as calcium, and the second messengers, such as cAMP, IP3, cADPR and calmodulin. The effect of specific peptide inhibitors of protein kinases on tyrosine hydroxylase phosphorylation is illustrated. Advantages and disadvantages of cell permeabilization procedures are discussed throughout the text.
Neurochemical Research 07/2000; 25(6):885-94. · 2.24 Impact Factor
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ABSTRACT: The S100 proteins are a family of calcium-binding proteins found in the central and peripheral nervous systems of vertebrates. S100beta, the most abundant member of this family in the CNS, mediates calcium signal transduction, and shows neurotrophic, gliotrophic and mitogenic actions that influence the development and maintenance of the nervous system. Another member of the S100 family (S100A10) was found to modulate phospholipid turnover by inhibiting the activity of enzyme phospholipase A2 (PLA2). We determined the concentration of S100beta protein in the plasma of 23 medicated schizophrenic patients and 23 healthy controls. S100beta protein accounts for 96% of the total S100 in the brain. Schizophrenic patients showed reduced S100beta concentrations (p=0.003), and this finding was not related to clinical variables or to intake of antipsychotic medication. Decreased S100beta could be related to the findings of increased PLA2 activity and to brain maldevelopment in schizophrenia. These results are discussed further with respect to the role of adenosine in S100beta release.
Schizophrenia Research 07/2000; 43(2-3):91-5. · 4.75 Impact Factor
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Neurology 06/2000; 54(10):2021-2. · 8.31 Impact Factor
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ABSTRACT: S100B is a calcium binding protein expressed and secreted by astrocytes. Extracellular S100B stimulates the proliferation of astroglial cells and the survival of neurons. Extracellular signal regulated kinases (ERK) are involved in the transduction of proliferating signals in astrocytes. Here we report that S100B significantly increases the activity of ERK in primary cultures of astrocytes, a result which may be related to previous observations of the effect of this protein on glial proliferation. We further confirm that conversion of S100B to its covalent dimer by oxidation of cysteine residues increases its extracellular activity. Although we cannot exclude S100B involvement in other mechanisms of signal transduction, these results suggest that ERK activity in astrocytes is modulated by extracellular S100B.
Neuroreport 04/2000; 11(4):807-9. · 1.66 Impact Factor
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ABSTRACT: Cycles of assembly/disassembly of the intermediate filaments of astrocytes are modulated by the phosphorylation of glial fibrillary acidic protein (GFAP). The sites on GFAP are localized at the N-terminal where they are phosphorylated by cAMP-dependent and Ca(2+)-dependent protein kinases. Phosphorylation of GFAP has been investigated in brain slices, astrocyte cultures, cytoskeletal fractions and purified systems. Here we describe a different approach to study GFAP phosphorylation. We show that permeabilization of astrocytes in culture with digitonin allows direct access to the systems phosphorylating GFAP. Conditions for the permeabilization were established with an assay based on the exclusion of Trypan blue. Incubation of permeabilized cells with cAMP and Ca(2+) increased the phosphorylation state of GFAP. Immunocytochemistry with anti-GFAP showed that permeabilized astrocytes retained their typical flat, fibroblast morphology and exhibited well preserved glial filaments. On incubation with cAMP the filaments apparently condensed to form long processes. The results suggest the approach of studying structural changes in glial filaments in parallel to protein phosphorylation, in the presence of specific modulators of protein kinases and phosphatases has considerable potential.
Brain Research 02/2000; 853(1):32-40. · 2.73 Impact Factor
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ABSTRACT: A method for simultaneous measurement of tyrosine hydroxylase (TH) activation and phosphorylation in permeabilised and intact bovine adrenal chromaffin cells (BACCs) was established. Permeabilised cells were stimulated with cyclic AMP (1--10 microM) in the presence of [32P]ATP and L-[carboxyl-(14)C]tyrosine. Intact BACCs were preincubated with 32P(i) for 3 h and stimulated with forskolin (1--5 microM) in the presence of L-[carboxyl-(14)C]tyrosine. On stimulation each well was covered with a sealed 'chimney' fitted with a small plastic cup containing 300 microl of 1.0 M NaOH that trapped the 14CO(2) released. TH activity was determined by measuring 14C radioactivity. TH phosphorylation was measured in the same cells by separating the solubilized proteins on SDS PAGE followed by autoradiography and/or HPLC analysis. It was found that H89, a protein kinase A inhibitor, significantly blocked both TH phosphorylation and activation in response to cyclic AMP in permeabilised cells. However, in intact cells, H89 was effective only in respect to forskolin-stimulated TH activity and did not block the forskolin-stimulated TH phosphorylation of Ser-40. The reason(s) for this lack of correlation between TH activation and phosphorylation is presently not understood.
Journal of Neuroscience Methods 04/1999; 87(2):167-74. · 1.98 Impact Factor
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ABSTRACT: The S100B protein belongs to a family of small Ca2+-binding proteins involved in several functions including cytoskeletal reorganization. The effect of S 100B on protein phosphorylation was investigated in a cytoskeletal fraction prepared from immature rat hippocampus. An inhibitory effect of 5 microM S100B on total protein phosphorylation, ranging from 25% to 40%, was observed in the presence of Ca2+ alone, Ca2+ plus calmodulin or Ca2+ plus cAMP. Analysis by two dimensional electrophoresis revealed a Ca2+/calmodulin-dependent and a Ca2+/cAMP-dependent inhibitory effect of S100B, ranging from 62% to 67% of control, on the phosphorylation of the intermediate filament proteins glial fibrillary acidic protein (GFAP) and vimentin. The fact that S100B binds to the N-terminal domain of GFAP and that the two proteins are co-localized in astrocytes suggests a potential in vivo role for S100B in modulating the phosphorylation of intermediate filament proteins in glia.
Neurochemical Research 11/1998; 23(10):1259-63. · 2.24 Impact Factor
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ABSTRACT: The effect of glutamate and lack of external Ca2+ on the phosphorylation of the astrocyte cell marker glial fibrillary acidic protein (GFAP) was studied in slices of hippocampus and thoracic spinal cord from immature (P12-16) rats. Confirming previous work with immature hippocampal slices (Wofchuk, S.T. and Rodnight, R., Neurochem. Int., 24 (1994) 517-523; Wofchuk, S.T. and Rodnight, R., Dev. Brain Res., 85 (1995) 181-186), glutamate strongly stimulated GFAP phosphorylation in media with Ca2+ and in media lacking Ca2+ a quantitatively similar stimulation of basal GFAP phosphorylation was observed. By contrast in slices of immature thoracic spinal cord, glutamate had no effect on GFAP phosphorylation and in media lacking Ca2+ phosphorylation of GFAP was inhibited. Since GFAP phosphorylation is Ca2+-dependent and is not stimulated by glutamate in slices of adult hippocampus, the present results suggest that astrocytic functions in the rat spinal cord mature more rapidly than in the hippocampus. The possibility that the difference in the control of GFAP phosphorylation in the two structures is related to differences in the control of GFAP dephosphorylation was investigated by incubating spinal cord slices with the calcineurin inhibitor FK506 in the presence of Ca2+. In contrast to results obtained with hippocampal slices FK506 had no effect on the phosphorylation state of GFAP in spinal cord slices.
Neuroscience Letters 06/1998; 248(2):141-3. · 2.11 Impact Factor
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ABSTRACT: Evidence was sought for a role for Ca2+ in the dephosphorylation of the astrocyte marker glial fibrillary acidic protein (GFAP) in immature hippocampal slices. Although previous work showed that the main phosphatase dephosphorylating GFAP in this preparation is a Ca2+-independent type 1 enzyme, a role for Ca2+ was suggested by the observation that the incorporation of [32P]phosphate into GFAP in immature slices is inhibited by external Ca2+. This inhibition is strikingly different to the situation in mature slices where GFAP phosphorylation is completely dependent on Ca2+. Pure astrocyte cultures were probed by immunoblotting for the presence of the Ca2+-dependent phosphatase calcineurin. An enzyme content, amounting to about 2% of that found in fresh hippocampal tissue, was detected for both the catalytic (alpha) and regulatory (beta) subunits. The direct or indirect association of calcineurin with GFAP was suggested by observations showing that FK506, a specific inhibitor of calcineurin, increased the phosphorylation state of GFAP in immature slices and of GFAP and vimentin in astrocyte cultures.
Developmental Brain Research 01/1998; 104(1-2):11-7. · 1.78 Impact Factor
