RESUMEN

BACKGROUND: Stroke is a leading cause of death and disability worldwide. A major factor in brain damage following ischemia is excitotoxicity caused by elevated levels of the neurotransmitter glutamate. In the brain, glutamate homeostasis is a primary function of astrocytes. Amburana cearensis has long been used in folk medicine and seed extract obtained with dichloromethane (EDAC) have previously been shown to exhibit cytoprotective activity in vitro. The aim of the present study was to analyse the activity of EDAC in hippocampal brain slices. METHODS: We prepared a dichloromethane extract (EDAC) from A. cearensis seeds and characterized the chemical constituents by 1H and 13C-NMR. Hippocampal slices from P6-8 or P90 Wistar rats were used for cell viability assay or glutamate uptake test. Hippocampal slices from P10-12 transgenic mice SOX10-EGFP and GFAP-EGFP and immunofluorescence for GS, GLAST and GLT1 were used to study oligodendrocytes and astrocytes. RESULTS: Astrocytes play a critical role in glutamate homeostasis and we provide immunohistochemical evidence that in excitotoxicity EDAC increased expression of glutamate transporters and glutamine synthetase, which is essential for detoxifying glutamate. Next, we directly examined astrocytes using transgenic mice in which glial fibrillary acidic protein (GFAP) drives expression of enhanced green fluorescence protein (EGFP) and show that glutamate excitotoxicity caused a decrease in GFAP-EGFP and that EDAC protected against this loss. This was examined further in the oxygen-glucose deprivation (OGD) model of ischemia, where EDAC caused an increase in astrocytic process branching, resulting in an increase in GFAP-EGFP. Using SOX10-EGFP reporter mice, we show that the acute response of oligodendrocytes to OGD in hippocampal slices is a marked loss of their processes and EDAC protected oligodendrocytes against this damage. CONCLUSION: This study provides evidence that EDAC is cytoprotective against ischemia and glutamate excitotoxicity by modulating astrocyte responses and stimulating their glutamate homeostatic mechanisms.

Asunto(s)

Astrocitos , Ácido Glutámico , Ratas , Ratones , Animales , Ácido Glutámico/metabolismo , Ratas Wistar , Cloruro de Metileno/metabolismo , Hipocampo/metabolismo , Isquemia/metabolismo , Ratones Transgénicos , Oxígeno/metabolismo , Extractos Vegetales/farmacología , Extractos Vegetales/metabolismo , Homeostasis , Oligodendroglía/metabolismo , Semillas

RESUMEN

OBJECTIVES: In this study, an in vivo model of Aß toxicity was used to investigate the effects of this peptide and the treatment with genistein on the lipid composition (gangliosides, phospholipids and cholesterol) in the frontal cortex of rats. METHODS: Male Wistar rats received bilateral intracerebroventricular infusions of Aß1-42 (2 nmol) and genistein 10 mg/kg orally for 10 days. Frontal cortex was homogenized with chloroform:methanol for lipid extraction and ganglioside, phospholipid and cholesterol levels were evaluated. RESULTS: The Aß-infused animals showed a significant decrease in ganglioside concentration and relative reduction of GD1b and GQ1b species. Treatment with genistein prevented the decrease in ganglioside levels. Phospholipid and cholesterol contents did not show significant differences. DISCUSSION: Considering the roles of gangliosides on neuronal function, findings described here can contribute to the knowledge of the potential neuroprotective mechanisms of genistein against Aß-induced alterations in the frontal cortex of rats and provide a novel view in the multifaceted scenario associated with its beneficial effects.

Asunto(s)

Péptidos beta-Amiloides , Lóbulo Frontal , Gangliósidos , Genisteína , Péptidos beta-Amiloides/toxicidad , Animales , Colesterol/química , Lóbulo Frontal/química , Gangliósidos/química , Genisteína/farmacología , Masculino , Fragmentos de Péptidos/toxicidad , Fosfolípidos/química , Ratas , Ratas Wistar

RESUMEN

The Developmental Origins of Health and Disease (DOHaD) states that intrauterine maternal environment influences postnatal life by programming offspring's metabolism. Intrauterine milieu induced by exercise during pregnancy promotes long-lasting benefits to the offspring's health and seems to offer some resistance against chronic diseases in adult life. Alzheimer's disease is a public health concern with limited treatment options. In the present study, we assessed the potential of maternal exercise during pregnancy in long-term programming of young adult male rat offspring's cerebellar metabolism in conferring neuroprotection against amyloid-ß (Aß) neurotoxicity. Female Wistar rats were submitted to a swimming protocol 1 week prior mating and throughout pregnancy (five sessions/a week lasting 30 min). Aß oligomers were infused bilaterally in the brain ventricles of 60-day-old male offspring. Fourteen days after surgery, we measured parameters related to redox state, mitochondrial function, and the immunocontent of proteins related to synaptic function. We found that maternal exercise during pregnancy attenuated several parameters in the offspring's male rat cerebellum, such as the reactive species rise, the increase of inducible nitric oxide synthase immunocontent and tau phosphorylation induced by Aß oligomers, increased mitochondrial fission indicated by dynamin-related protein 1 (DRP1), and protein oxidation identified by carbonylation. Strikingly, we find that maternal exercise promotes changes in the rat offspring's cerebellum that are still evident in young adult life. These favorable neurochemical changes in offspring's cerebellum induced by maternal exercise may contribute to a protective phenotype against Aß-induced neurotoxicity in young adult male rat offspring.

Asunto(s)

Péptidos beta-Amiloides/metabolismo , Cerebelo/patología , Condicionamiento Físico Animal/fisiología , Efectos Tardíos de la Exposición Prenatal/prevención & control , Animales , Cerebelo/metabolismo , Modelos Animales de Enfermedad , Femenino , Humanos , Masculino , Oxidación-Reducción , Embarazo , Efectos Tardíos de la Exposición Prenatal/metabolismo , Efectos Tardíos de la Exposición Prenatal/patología , Ratas , Ratas Wistar

RESUMEN

Alzheimer's disease is a neurodegenerative disorder characterized by extracellular deposition of amyloid-ß (Aß) peptide and hyperphosphorylation of Tau protein, which ultimately leads to the formation of intracellular neurofibrillary tangles and cell death. Increasing evidence indicates that genistein, a soy isoflavone, has neuroprotective effects against Aß-induced toxicity. However, the molecular mechanisms involved in its neuroprotection are not well understood. In this study, we have established a neuronal damage model using retinoic-acid differentiated SH-SY5Y cells treated with different concentrations of Aß25-35 to investigate the effect of genistein against Aß-induced cell death and the possible involvement of protein kinase B (PKB, also termed Akt), glycogen synthase kinase 3ß (GSK-3ß), and Tau as an underlying mechanism to this neuroprotection. Differentiated SH-SY5Y cells were pre-treated for 24 hr with genistein (1 and 10 nM) and exposed to Aß25-35 (25 µM), and we found that genistein partially inhibited Aß induced cell death, primarily apoptosis. Furthermore, the protective effect of genistein was associated with the inhibition of Aß-induced Akt inactivation and Tau hyperphosphorylation. These findings reinforce the neuroprotective effects of genistein against Aß toxicity and provide evidence that its mechanism may involve regulation of Akt and Tau proteins.

Asunto(s)

Péptidos beta-Amiloides/toxicidad , Genisteína/farmacología , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Animales , Apoptosis/efectos de los fármacos , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Humanos , Neuronas/fisiología , Fosforilación/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal/efectos de los fármacos , Proteínas tau/efectos de los fármacos , Proteínas tau/metabolismo

RESUMEN

A redispersible spray-dried formulation containing curcumin-loaded, lipid-core nanocapsules (LNC-C) was developed for oral administration. The neuroprotective activity of curcumin after the spray-drying process was evaluated in vitro. The spray-dried powder (SD-LNC-C) was produced using a drying adjuvant composed of a blend of maltodextrin and L-leucine (90:10 w/w). Acceptable process yield (~ 70%) and drug content (6.5 ± 0.2 mg g-1) were obtained. SD-LNC-C was formed by smooth, spherical-shaped particles, and confocal Raman analysis indicated the distribution of the LNC-C on the surface of the leucine/maltodextrin agglomerates. The surface of the agglomerates was formed by a combination of LNC-C and adjuvants, and laser diffraction showed that SD-LNC-C had adequate aqueous redispersion, with no loss of controlled drug release behaviour of LNC-C. The in vitro curcumin activity against the lipopolysaccharide (LPS)-induced proinflammatory response in organotypic hippocampal slice cultures was evaluated. Both formulations (LNC-C and SD-LNC-C) reduced TNF-α to similar levels. Therefore, neuroprotection of curcumin in vitro may be improved by nanoencapsulation followed by spray-drying, with no loss of this superior performance. Hence, the redispersible spray-dried powder proposed here represents a suitable approach for the development of innovative nanomedicines containing curcumin for the prevention/treatment of neurodegenerative diseases.

Asunto(s)

Curcumina/farmacología , Desecación/métodos , Neuroprotección/efectos de los fármacos , Administración Oral , Animales , Curcumina/administración & dosificación , Curcumina/química , Hipocampo/efectos de los fármacos , Técnicas In Vitro , Masculino , Nanocápsulas , Tamaño de la Partícula , Polisacáridos/química , Polvos , Ratas Wistar

RESUMEN

Alzheimer's disease (AD) is the main aging-associated neurodegenerative disorder and is characterized by mitochondrial dysfunction, oxidative stress, synaptic failure, and cognitive decline. It has been a challenge to find disease course-modifying treatments. However, several studies demonstrated that regular physical activity and exercise are capable of promoting brain health by improving the cognitive function. Maternal lifestyle, including regular exercise during pregnancy, has also been shown to influence fetal development and disease susceptibility in adulthood through fetal metabolism programming. Here, we investigated the potential neuroprotective role of regular maternal swimming, before and during pregnancy, against amyloid-ß neurotoxicity in the adult offspring. Behavioral and neurochemical analyses were performed 14 days after male offspring received a single, bilateral, intracerebroventricular (icv) injection of amyloid-ß oligomers (AßOs). AßOs-injected rats of the sedentary maternal group exhibited learning and memory deficits, along with reduced synaptophysin, brain-derived neurotrophic factor (BDNF) levels, and alterations of mitochondrial function. Strikingly, the offspring of the sedentary maternal group had AßOs-induced behavioral alterations that were prevented by maternal exercise. This effect was accompanied by preventing the alteration of synaptophysin levels in the offspring of exercised dams. Additionally, offspring of the maternal exercise group exhibited an augmentation of functional mitochondria, as indicated by increases in mitochondrial mass and membrane potential, α-ketoglutarate dehydrogenase, and cytochrome c oxidase enzymes activities. Moreover, maternal exercise during pregnancy induced long-lasting modulation of fusion and fission proteins, Mfn1 and Drp1, respectively. Overall, our data demonstrates a potential protective effect of exercise during pregnancy against AßOs-induced neurotoxicity in the adult offspring brain, by mitigating the neurodegenerative process triggered by Alzheimer-associated AßOs through programming the brain metabolism.

Asunto(s)

Péptidos beta-Amiloides , Encéfalo/metabolismo , Trastornos del Conocimiento/prevención & control , Condicionamiento Físico Animal/fisiología , Efectos Tardíos de la Exposición Prenatal/metabolismo , Animales , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Trastornos del Conocimiento/inducido químicamente , Trastornos del Conocimiento/metabolismo , Femenino , Masculino , Mitocondrias/metabolismo , Embarazo , Ratas , Ratas Wistar , Sinaptofisina/metabolismo

RESUMEN

Several environmental factors affect child development, such as the intrauterine environment during the embryonic and fetal development and early postnatal environment provided by maternal behavior. Although mechanistic effects of maternal exercise on offspring health improvement are not yet completely understood, the number of reports published demonstrating the positive influence of maternal exercise have increase. Herein, we addressed issues related to early postnatal environment provided by maternal behavior and early developmental physical landmarks, sensorimotor reflexes, and motor movements ontogeny. In brief, adult female rats underwent involuntary swimming exercise, in a moderated intensity, one week before mating and throughout pregnancy, 30 min a day, 5 days a week. Maternal exercised dams have unchanged gestational outcomes compared to sedentary dams. We found no differences concerning the frequency of pup-directed behavior displayed by dams. However, sedentary dams displayed a poorer pattern of maternal care quality during dark cycle than exercised dams. Physical landmarks and sensorimotor reflexes development of female and male littermates did not differ between maternal groups. Developmental motor parameters such as immobility, lateral head movements, head elevation, pivoting, rearing with forelimb support and crawling frequencies did not differ between groups. Pups born to exercised dams presented higher frequency of walking and rearing on the hind legs. These data suggest that female and male littermates of exercised group present a high frequency of exploratory behavior over sedentary littermates. Taken together, the present findings reinforce that maternal exercise throughout pregnancy represent a window of opportunity to improve offspring's postnatal health.

Asunto(s)

Conducta Materna , Condicionamiento Físico Animal/métodos , Resultado del Embarazo , Efectos Tardíos de la Exposición Prenatal/prevención & control , Efectos Tardíos de la Exposición Prenatal/fisiopatología , Natación/fisiología , Factores de Edad , Análisis de Varianza , Animales , Animales Recién Nacidos , Conducta Exploratoria/fisiología , Femenino , Actividad Motora/fisiología , Embarazo , Ratas , Ratas Wistar , Reflejo/fisiología

RESUMEN

Glioblastoma is the most frequent and malignant brain tumor. Treatment includes chemotherapy with temozolomide concomitant with surgical resection and/or irradiation. However, a number of cases are resistant to temozolomide, as well as the human glioblastoma cell line U138-MG. We investigated doxazosin's (an antihypertensive drug) activity against glioblastoma cells (C6 and U138-MG) and its neurotoxicity on primary astrocytes and organoptypic hippocampal cultures. For this study, the following methods were used: citotoxicity assays, flow cytometry, western-blotting and confocal microscopy. We showed that doxazosin induces cell death on C6 and U138-MG cells. We observed that doxazosin's effects on the PI3K/Akt pathway were similar as LY294002 (PI3K specific inhibitor). In glioblastoma cells treated with doxasozin, Akt levels were greatly reduced. Upon examination of activities of proteins downstream of Akt we observed upregulation of GSK-3ß and p53. This led to cell proliferation inhibition, cell death induction via caspase-3 activation and cell cycle arrest at G0/G1 phase in glioblastoma cells. We used in this study Lapatinib, a tyrosine kinase inhibitor, as a comparison with doxazosin because they present similar chemical structure. We also tested the neurocitotoxicity of doxazosin in primary astrocytes and organotypic cultures and observed that doxazosin induced cell death on a small percentage of non-tumor cells. Aggressiveness of glioblastoma tumors and dismal prognosis require development of new treatment agents. This includes less toxic drugs, more selective towards tumor cells, causing less damage to the patient. Therefore, our results confirm the potential of doxazosin as an attractive therapeutic antiglioma agent.

Asunto(s)

Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Neoplasias Encefálicas/tratamiento farmacológico , Doxazosina/farmacología , Glioblastoma/tratamiento farmacológico , Inhibidores de las Quinasa Fosfoinosítidos-3 , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/biosíntesis , Animales , Astrocitos/efectos de los fármacos , Caspasa 3/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Cromonas/farmacología , Doxazosina/toxicidad , Activación Enzimática/efectos de los fármacos , Puntos de Control de la Fase G1 del Ciclo Celular/efectos de los fármacos , Glucógeno Sintasa Quinasa 3 beta/biosíntesis , Hipocampo/efectos de los fármacos , Humanos , Lapatinib , Morfolinas/farmacología , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Quinazolinas/farmacología , Ratas , Ratas Wistar

RESUMEN

BACKGROUND/AIM: Despite recent progress in glioblastoma treatment, prognosis is still poor. Monastrol is a kinesin spindle protein (KSP) inhibitor and anticancer effects for this molecule have been reported. Here we describe the effect of LaSOM 65, a monastrol derivated compound, against glioma cell lines. MATERIALS AND METHODS: Cell counting, viability assay, lactate dehydrogenase (LDH) activity, cell-cycle analysis, immunofluorescence and organotypic hippocampal slice cultures were performed. RESULTS: LaSOM 65 reduced cell number and cell viability of gliomas cells, but did not cause arrest in the cell cycle at the G2/M phase. Measurement of LDH activity showed that LaSOM 65 induces necrosis after 48 h of treatment. CONCLUSION: LaSOM 65 appears to a be promising new molecule to treat glioblastoma since it promotes a decrease of cell growth and cell viability of glioma cells in vitro and does not induces the neurotoxic characteristics of the anti-mitotic drugs currently used.

Asunto(s)

Antineoplásicos/farmacología , Pirimidinas/farmacología , Tionas/farmacología , Animales , Puntos de Control del Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Núcleo Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Glioblastoma , Hipocampo/efectos de los fármacos , Humanos , L-Lactato Deshidrogenasa/metabolismo , Necrosis , Ratas , Técnicas de Cultivo de Tejidos , Tubulina (Proteína)/metabolismo

RESUMEN

Alzheimer's disease (AD) is a neurodegenerative disorder whose pathogenesis involves production and aggregation of amyloid-ß peptide (Aß). Aß-induced toxicity is believed to involve alterations on as Na(+),K(+)-ATPase and acetylcholinesterase (AChE) activities, prior to neuronal death. Drugs able to prevent or to reverse these biochemical changes promote neuroprotection. GM1 is a ganglioside proposed to have neuroprotective roles in AD models, through mechanisms not yet fully understood. Therefore, this study aimed to investigate the effect of Aß1-42 infusion and GM1 treatment on recognition memory and on Na(+),K(+)-ATPase and AChE activities, as well as, on antioxidant defense in the brain cortex and the hippocampus. For these purposes, Wistar rats received i.c.v. infusion of fibrilar Aß1-42 (2 nmol) and/or GM1 (0.30 mg/kg). Behavioral and biochemical analyses were conducted 1 month after the infusion procedures. Our results showed that GM1 treatment prevented Aß-induced cognitive deficit, corroborating its neuroprotective function. Aß impaired Na(+),K(+)-ATPase and increase AChE activities in hippocampus and cortex, respectively. GM1, in turn, has partially prevented Aß-induced alteration on Na(+),K(+)-ATPase, though with no impact on AChE activity. Aß caused a decrease in antioxidant defense, specifically in hippocampus, an effect that was prevented by GM1 treatment. GM1, both in cortex and hippocampus, was able to increase antioxidant scavenge capacity. Our results suggest that Aß-triggered cognitive deficit involves region-specific alterations on Na(+),K(+)-ATPase and AChE activities, and that GM1 neuroprotection involves modulation of Na(+),K(+)-ATPase, maybe by its antioxidant properties. Although extrapolation from animal findings is difficult, it is conceivable that GM1 could play an important role in AD treatment.

Asunto(s)

Acetilcolinesterasa/metabolismo , Péptidos beta-Amiloides/farmacología , Gangliósido G(M1)/farmacología , Fármacos Neuroprotectores/farmacología , Fragmentos de Péptidos/farmacología , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Acetilcolinesterasa/efectos de los fármacos , Animales , Inyecciones Intraventriculares , Masculino , Memoria/efectos de los fármacos , Ratas , Ratas Wistar , ATPasa Intercambiadora de Sodio-Potasio/efectos de los fármacos

RESUMEN

Physical activity has been related to antioxidant adaptations, which is associated with health benefits, including those to the nervous system. Additionally, available data suggest exercise and a caloric restriction regimen may reduce both the incidence and severity of neurological disorders. Therefore, our aim was to compare hippocampal redox status and glial parameters among sedentary, trained, caloric-restricted sedentary and caloric-restricted trained rats. Forty male adult rats were divided into 4 groups: ad libitum-fed sedentary (AS), ad libitum-fed exercise training (AE), calorie-restricted sedentary (RS) and calorie-restricted exercise training (RE). The caloric restriction (decrease of 30% in food intake) and exercise training (moderate in a treadmill) were carried out for 3 months. Thereafter hippocampus was surgically removed, and then redox and glial parameters were assessed. Increases in reduced glutathione (GSH) levels and total antioxidant reactivity (TAR) were observed in AE, RS and RE. The nitrite/nitrate levels decreased only in RE. We found a decrease in carbonyl content in AE, RS and RE, while no modifications were detected in thiobarbituric acid reactive substances (TBARS). Total reactive antioxidant potential (TRAP), superoxide dismutase (SOD) activity, S100B and glial fibrilary acid protein (GFAP) content did not change, but caloric restriction was able to increase glutamine synthetase (GS) activity in RS and glutamate uptake in RS and RE. Exercise training, caloric restriction and both combined can decrease oxidative damage in the hippocampus, possibly involving modulation of astroglial function, and could be used as a strategy for the prevention of neurodegenerative diseases.

Asunto(s)

Astrocitos/metabolismo , Restricción Calórica , Hipocampo/metabolismo , Oxidación-Reducción , Condicionamiento Físico Animal/fisiología , Animales , Masculino , Ratas , Ratas Wistar

RESUMEN

The effect of Aß25-35 peptide, in its fibrillar and non-fibrillar forms, on ganglioside expression in organotypic hippocampal slice cultures was investigated. Gangliosides were endogenously labeled with D-[1-C(14)] galactose and results showed that Aß25-35 affected ganglioside expression, depending on the peptide aggregation state, that is, fibrillar Aß25-35 caused an increase in GM3 labeling and a reduction in GD1b labeling, whereas the non-fibrillar form was able to enhance GM1 expression. Interestingly, GM1 exhibited a neuroprotective effect in this organotypic model, since pre-treatment of the hippocampal slices with GM1 10 µM was able to prevent the toxicity triggered by the fibrillar Aß25-35, when measured by propidium iodide uptake protocol. With the purpose of further investigating a possible mechanism of action, we analyzed the effect of GM1 treatment (1, 6, 12 and 24h) upon the Aß-induced alterations on GSK3ß dephosphorylation/activation state. Results demonstrated an important effect after 24-h incubation, with GM1 preventing the Aß-induced dephosphorylation (activation) of GSK3ß, a signaling pathway involved in apoptosis triggering and neuronal death in models of Alzheimer's disease. Taken together, present results provide a new and important support for ganglioside participation in development of Alzheimer's disease experimental models and suggest a protective role for GM1 in Aß-induced toxicity. This may be useful for designing new therapeutic strategies for Alzheimer's treatment.

Asunto(s)

Péptidos beta-Amiloides/antagonistas & inhibidores , Péptidos beta-Amiloides/toxicidad , Gangliósido G(M1)/farmacología , Gangliósidos/biosíntesis , Fármacos Neuroprotectores , Fragmentos de Péptidos/antagonistas & inhibidores , Fragmentos de Péptidos/toxicidad , Animales , Western Blotting , Muerte Celular/efectos de los fármacos , Cromatografía en Capa Delgada , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , Masculino , Neurofibrillas/efectos de los fármacos , Neurofibrillas/metabolismo , Técnicas de Cultivo de Órganos , Fosforilación , Ratas , Ratas Wistar

RESUMEN

Accumulation of the neurotoxic amyloid beta-peptide (Abeta) in the brain is a hallmark of Alzheimer's disease (AD). Several synthetic Abeta peptides have been used to study the mechanisms of toxicity. Here, we sought to establish comparability between two commonly used Abeta peptides Abeta1-42 and Abeta25-35 on an in vitro model of Abeta toxicity. For this purpose we used organotypic slice cultures of rat hippocampus and observed that both Abeta peptides caused similar toxic effects regarding to propidium iodide uptake and caspase-3 activation. In addition, we also did not observe any effect of both peptides on Akt and PTEN phosphorylation; otherwise the phosphorylation of GSK-3beta was increased. Although further studies are necessary for understanding mechanisms underlying Abeta peptide toxicity, our results provide strong evidence that Abeta1-42 and the Abeta25-35 peptides induce neural injury in a similar pattern and that Abeta25-35 is a convenient tool for the investigation of neurotoxic mechanisms involved in AD.

Asunto(s)

Péptidos beta-Amiloides/toxicidad , Hipocampo/efectos de los fármacos , Fragmentos de Péptidos/toxicidad , Animales , Western Blotting , Caspasa 3/metabolismo , Activación Enzimática , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Hipocampo/enzimología , Hipocampo/metabolismo , Técnicas In Vitro , Fosfohidrolasa PTEN/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas

RESUMEN

1. The effect of guanosine on L-[2,3-3H]glutamate uptake was investigated in brain cortical slices under normal or oxygen-glucose deprivation (OGD) conditions. 2. In slices exposed to physiological conditions, guanosine (1-100 microM) stimulated glutamate uptake (up to 100%) in a concentration-dependent manner when a high (100 microM) but not a low (1 microM) concentration of glutamate was used. 3. In slices submitted to OGD, guanosine 1 and 100 microM also increased 100 microM glutamate uptake (38 and 70%, respectively). 4. The increasing of glutamate and taurine released to the incubation medium in cortical slices submitted to OGD were significantly attenuated by the presence of guanosine in the incubation medium. 5. Guanosine prevented the increase in propidium iodide incorporation into cortical slices induced by OGD, indicating a protective role against ischemic injury. 6. These results support the hypothesis of a protective role for guanosine during brain ischemia, possibly by activating glutamate uptake into neural cells.

Asunto(s)

Corteza Cerebral/efectos de los fármacos , Ácido Glutámico/metabolismo , Guanosina/farmacología , Hipoxia-Isquemia Encefálica/tratamiento farmacológico , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Sinapsis/efectos de los fármacos , Animales , Muerte Celular/efectos de los fármacos , Muerte Celular/fisiología , Corteza Cerebral/metabolismo , Corteza Cerebral/fisiopatología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/fisiología , Ácido Glutámico/farmacología , Guanosina/metabolismo , Hipoxia-Isquemia Encefálica/metabolismo , Hipoxia-Isquemia Encefálica/fisiopatología , Masculino , Neuronas/metabolismo , Fármacos Neuroprotectores/metabolismo , Neurotoxinas/metabolismo , Neurotoxinas/farmacología , Ratas , Ratas Wistar , Sinapsis/metabolismo , Taurina/metabolismo

RESUMEN

Two dimensional polyacrylamide gel electrophoresis was performed in seminal plasma of seven Bos taurus taurus and seven Bos taurus indicus bulls with high semen freezability, from an artificial insemination center. In a 8% polyacrylamide gels, three bands of 195, 66 and 55 kDa, present in 100% of the samples in both sub-species, were analyzed by their optical densities. In Bos taurus samples, the opticals densities of 55 kDa band, imunoidentified as osteopontin were superior (p < 0.05) than Bos indicus samples. The 66 kDa band was imunoidentified as albumin. In the Bos taurus samples, the bands did not show any variation among the bull samples, but in the Bos indicus, the albumin optical densities showed significant variation among samples.

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As proteínas do plasma seminal de 14 reprodutores (7 Bos taurus taurus e 7 Bos taurus indicus), foram analisadas por eletroforese bidimensional, em géis de poliacrilamida a 8%, corados por Comassie Blue. Três bandas protéicas, presentes em 100% das amostras de plasma seminal, foram quantificadas de acordo com a densidade óptica exibida: 195 kDa, pI 6,5-7,5 ; 66 kDa, pI 5,4 e 55 kDa, pI 4,5. As amostras de plasma seminal provenientes de taurinos apresentaram densidades ópticas significativamente superiores (p < 0,05) às dos zebuínos na banda