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1.
Cell Physiol Biochem ; 54(2): 180-194, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32068980

RESUMO

BACKGROUND/AIMS: Still in 1999 the first hints were published for the pharmacoresistant Cav2.3 calcium channel to be involved in the generation of epileptic seizures, as transcripts of alpha1E (Cav2.3) and alpha1G (Cav3.1) are changed in the brain of genetic absence epilepsy rats from Strasbourg (GAERS). Consecutively, the seizure susceptibility of mice lacking Cav2.3 was analyzed in great detail by using 4-aminopyridine, pentylene-tetrazol, N-methyl-D-aspartate and kainic acid to induce experimentally convulsive seizures. Further, γ-hydroxybutyrolactone was used for the induction of non-convulsive absence seizures. For all substances tested, Cav2.3-competent mice differed from their knockout counterparts in the sense that for convulsive seizures the deletion of the pharmacoresistant channel was beneficial for the outcome during experimentally induced seizures [1]. The antiepileptic drug lamotrigine reduces seizure activity in Cav2.3-competent but increases it in Cav2.3-deficient mice. In vivo, Cav2.3 must be under tight control by endogenous trace metal cations (Zn2+ and Cu2+). The dyshomeostasis of either of them, especially of Cu2+, may alter the regulation of Cav2.3 severely and its activity for Ca2+ conductance, and thus may change hippocampal and neocortical signaling to hypo- or hyperexcitation. METHODS: To investigate by telemetric EEG recordings the mechanism of generating hyperexcitation by kainate, mice were tested for their sensitivity of changes in neuronal (intracerebroventricular) concentrations of the trace metal cation Zn2+. As the blood-brain barrier limits the distribution of bioavailable Zn2+ or Cu2+ into the brain, we administered micromolar Zn2+ ions intracerebroventricularly in the presence of 1 mM histidine as carrier and compared the effects on behavior and EEG activity in both genotypes. RESULTS: Kainate seizures are more severe in Cav2.3-competent mice than in KO mice and histidine lessens seizure severity in competent but not in Cav2.3-deficient mice. Surprisingly, Zn2+ plus histidine resembles the kainate only control with more seizure severity in Cav2.3-competent than in deficient mice. CONCLUSION: Cav2.3 represents one important Zn2+-sensitive target, which is useful for modulating convulsive seizures.


Assuntos
Canais de Cálcio Tipo R/metabolismo , Proteínas de Transporte de Cátions/metabolismo , Convulsões/tratamento farmacológico , Zinco/uso terapêutico , Animais , Canais de Cálcio Tipo R/genética , Proteínas de Transporte de Cátions/genética , Eletroencefalografia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Histidina/farmacologia , Íons/química , Ácido Caínico/toxicidade , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Convulsões/induzido quimicamente , Convulsões/patologia , Índice de Gravidade de Doença , Zinco/farmacologia , Ácido gama-Aminobutírico/metabolismo
2.
Invest Ophthalmol Vis Sci ; 60(14): 4532-4547, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31675424

RESUMO

Purpose: In the retina, growth hormone (GH) promotes axonal growth, synaptic restoration, and protective actions against excitotoxicity. Notch signaling pathway is critical for neural development and participates in the retinal neuroregenerative process. We investigated the interaction of GH with Notch signaling pathway during its neuroprotective effect against excitotoxic damage in the chicken retina. Methods: Kainate (KA) was used as excitotoxic agent and changes in the mRNA expression of several signaling markers were determined by qPCR. Also, changes in phosphorylation and immunoreactivity were determined by Western blotting. Histology and immunohistochemistry were performed for morphometric analysis. Overexpression of GH was performed in the quail neuroretinal-derived immortalized cell line (QNR/D) cell line. Exogenous GH was administered to retinal primary cell cultures to study the activation of signaling pathways. Results: KA disrupted the retinal cytoarchitecture and induced significant cell loss in several retinal layers, but the coaddition of GH effectively prevented these adverse effects. We showed that GH upregulates the Notch signaling pathway during neuroprotection leading to phosphorylation of the PI3K/Akt signaling pathways through downregulation of PTEN. In contrast, cotreatment of GH with the Notch signaling inhibitor, DAPT, prevented its neuroprotective effect against KA. We identified binding sites in Notch1 and Notch2 genes for STAT5. Also, GH prevented Müller cell transdifferentiation and downregulated Sox2, FGF2, and PCNA after cotreatment with KA. Additionally, GH modified TNF receptors immunoreactivity suggesting anti-inflammatory actions. Conclusions: Our data indicate that the neuroprotective effects of GH against KA injury in the retina are mediated through the regulation of Notch signaling. Additionally, anti-inflammatory and antiproliferative effects were observed.


Assuntos
Agonistas de Aminoácidos Excitatórios/toxicidade , Hormônio do Crescimento/uso terapêutico , Ácido Caínico/toxicidade , PTEN Fosfo-Hidrolase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores Notch/metabolismo , Retina/efeitos dos fármacos , Animais , Western Blotting , Células Cultivadas , Galinhas , Vetores Genéticos , Injeções Intravítreas , Fármacos Neuroprotetores/uso terapêutico , Reação em Cadeia da Polimerase em Tempo Real , Retina/metabolismo , Transdução de Sinais/fisiologia , Organismos Livres de Patógenos Específicos , Transfecção
3.
Int J Mol Sci ; 20(18)2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31509934

RESUMO

In addition to its role as an endocrine messenger, growth hormone (GH) also acts as a neurotrophic factor in the central nervous system (CNS), whose effects are involved in neuroprotection, axonal growth, and synaptogenic modulation. An increasing amount of clinical evidence shows a beneficial effect of GH treatment in patients with brain trauma, stroke, spinal cord injury, impaired cognitive function, and neurodegenerative processes. In response to injury, Müller cells transdifferentiate into neural progenitors and proliferate, which constitutes an early regenerative process in the chicken retina. In this work, we studied the long-term protective effect of GH after causing severe excitotoxic damage in the retina. Thus, an acute neural injury was induced via the intravitreal injection of kainic acid (KA, 20 µg), which was followed by chronic administration of GH (10 injections [300 ng] over 21 days). Damage provoked a severe disruption of several retinal layers. However, in KA-damaged retinas treated with GH, we observed a significant restoration of the inner plexiform layer (IPL, 2.4-fold) and inner nuclear layer (INL, 1.5-fold) thickness and a general improvement of the retinal structure. In addition, we also observed an increase in the expression of several genes involved in important regenerative pathways, including: synaptogenic markers (DLG1, NRXN1, GAP43); glutamate receptor subunits (NR1 and GRIK4); pro-survival factors (BDNF, Bcl-2 and TNF-R2); and Notch signaling proteins (Notch1 and Hes5). Interestingly, Müller cell transdifferentiation markers (Sox2 and FGF2) were upregulated by this long-term chronic GH treatment. These results are consistent with a significant increase in the number of BrdU-positive cells observed in the KA-damaged retina, which was induced by GH administration. Our data suggest that GH is able to facilitate the early proliferative response of the injured retina and enhance the regeneration of neurite interconnections.


Assuntos
Hormônio do Crescimento/farmacologia , Ácido Caínico/toxicidade , Regeneração/efeitos dos fármacos , Retina/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Fator Neurotrófico Derivado do Encéfalo/genética , Embrião de Galinha , Galinhas , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Neurogênese/genética , Neurogênese/fisiologia , Fármacos Neuroprotetores/farmacologia , Neurotoxinas/toxicidade , Receptor Notch1/genética , Regeneração/genética , Regeneração/fisiologia , Retina/metabolismo , Retina/fisiopatologia , Fatores de Transcrição SOXB1/genética
4.
Exp Neurol ; 322: 113054, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31499063

RESUMO

Xenon is an inhalation anesthetic with a favorable safety profile, and previous studies have demonstrated its neuroprotective efficacy. However, whether xenon plays a role in the treatment of epilepsy or seizure remains unclear. This study aimed to investigate the role of xenon inhalation and explore the role of different xenon ratio gradients and different delayed treatment times in seizure models. Kainic acid (KA)-induced status epilepticus and neonatal hypoxia-induced seizure models were used in our study. Animals were subject to inhalation of xenon mixture for 60 min after the stimulation used to induce seizures. The control group was treated with 70% nitrogen/30% oxygen, as in previous reports. Behavioral changes, electroencephalography, neuronal injury, and learning and memory function were investigated in each group. The results indicate that xenon mixture significantly reduced the severity of seizures and neurodegeneration in both KA-induced status epilepticus and in neonatal mice with hypoxia-induced seizure. Moreover, treatment with different percentages of xenon (35%, 50%, or 70%), as well as at different intervention time points (immediately, delayed for 15 min, delayed for 30 min) after hypoxia induction significantly attenuated the severity of seizure and neuronal injury. Additionally, 50% or 70% xenon treatment, as well as immediate xenon treatment or with a delay of 15 min attenuated the learning and memory impairments induced by hypoxia. This study confirmed that xenon mixture exerts strong inhibitive effects in seizure and seizure-induced neuronal injury and defects of cognitive function. Moreover, the results suggest that intervention time window and percentage of xenon influence the efficacy of the xenon treatment. Our study supports that xenon inhalation represents a safe means to inhibit seizures and neuronal injury.


Assuntos
Encéfalo/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Convulsões , Estado Epiléptico , Xenônio/farmacologia , Animais , Animais Recém-Nascidos , Encéfalo/patologia , Convulsivantes/toxicidade , Hipóxia Encefálica/complicações , Hipóxia Encefálica/patologia , Ácido Caínico/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Ratos Sprague-Dawley , Convulsões/etiologia , Convulsões/patologia , Estado Epiléptico/etiologia , Estado Epiléptico/patologia
5.
Int J Med Sci ; 16(8): 1180-1187, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31523181

RESUMO

Objective: The effects of pre-treatments from s-methyl cysteine (SMC) alone, syringic acid (SA) alone and SMC plus SA against kainic acid (KA) induced injury in nerve growth factor (NGF) differentiated PC12 cells were investigated. Methods: NGF-differentiated PC12 cells were treated with 1 µM SMC, 1 µM SA or 0.5 µM SMC plus 0.5 µM SA for 2 days. Subsequently, cells were further treated by 150 µM KA. Results: KA suppressed Bcl-2 mRNA expression, enhanced Bax mRNA expression and casued cell death. SMC was greater than SA, and similar as SMC+SA in increasing Bcl-2 mRNA expression. SMC+SA led to greater increase in mitochondrial membrane potential and cell survival than SMC or SA alone. SMC+SA resulted in more reduction in reactive oxygen species and tumor necrosis factor-alpha generation, more increase in glutathione content and glutathione reductase activity than SMC or SA alone. KA up-regulated protein expression of nuclear factor kappa B (NF-κB) p65 and phosphorylated p38 (p-p38). SMC or SA pre-treatments alone limited protein expression of both factors. SMC+SA resulted in more suppression in NF-κB p65 and p-p38 expression. KA decreased glutamine level, increased glutamate level and stimulated calcium release. SMC pre-treatments alone reversed these alterations. SMC alone elevated glutamine synthetase (GS) activity and mRNA expression. SMC+SA led to greater GS activity and mRNA expression than SMC pre-treatments alone. Conclusion: These findings suggested that this combination, SMC+SA, might provide greater protective potent for neuronal cells.


Assuntos
Cisteína/análogos & derivados , Ácido Gálico/análogos & derivados , Fator de Crescimento Neural/farmacologia , Fármacos Neuroprotetores/farmacologia , Animais , Cálcio/metabolismo , Diferenciação Celular/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Membrana Celular/patologia , Sobrevivência Celular , Cisteína/farmacologia , Sinergismo Farmacológico , Ácido Gálico/farmacologia , Ácido Caínico/toxicidade , Potencial da Membrana Mitocondrial/efeitos dos fármacos , NF-kappa B/antagonistas & inibidores , NF-kappa B/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Células PC12 , Ratos , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
6.
Epilepsy Res ; 151: 48-66, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30831337

RESUMO

Network-based approaches in drug discovery comprise both development of novel drugs interacting with multiple targets and repositioning of drugs with known targets to form novel drug combinations that interact with cellular or molecular networks whose function is disturbed in a disease. Epilepsy is a complex network phenomenon that, as yet, cannot be prevented or cured. We recently proposed multitargeted, network-based approaches to prevent epileptogenesis by combinations of clinically available drugs chosen to impact diverse epileptogenic processes. In order to test this strategy preclinically, we developed a multiphase sequential study design for evaluating such drug combinations in rodents, derived from human clinical drug development phases. Because pharmacokinetics of such drugs are known, only the tolerability of novel drug combinations needs to be evaluated in Phase I in öhealthy" controls. In Phase IIa, tolerability is assessed following an epileptogenic brain insult, followed by antiepileptogenic efficacy testing in Phase IIb. Here, we report Phase I and Phase IIa evaluation of 7 new drug combinations in mice, using 10 drugs (levetiracetam, topiramate, gabapentin, deferoxamine, fingolimod, ceftriaxone, α-tocopherol, melatonin, celecoxib, atorvastatin) with diverse mechanisms thought to be important in epileptogenesis. Six of the 7 drug combinations were well tolerated in mice during prolonged treatment at the selected doses in both controls and during the latent phase following status epilepticus induced by intrahippocampal kainate. However, none of the combinations prevented hippocampal damage in response to kainate, most likely because treatment started only 16-18 h after kainate. This suggests that antiepileptogenic or disease-modifying treatment may need to start earlier after the brain insult. The present data provide a rich collection of tolerable, network-based combinatorial therapies as a basis for antiepileptogenic or disease-modifying efficacy testing.


Assuntos
Anticonvulsivantes/uso terapêutico , Quimioterapia Combinada/métodos , Fármacos Neuroprotetores/uso terapêutico , Estado Epiléptico/tratamento farmacológico , Animais , Anticonvulsivantes/farmacocinética , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Vias de Administração de Medicamentos , Agonistas de Aminoácidos Excitatórios/toxicidade , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Ácido Caínico/toxicidade , Masculino , Camundongos , Fármacos Neuroprotetores/farmacocinética , Transtornos Psicomotores/etiologia , Estado Epiléptico/induzido quimicamente , Estado Epiléptico/complicações , Estado Epiléptico/patologia
7.
Neurotoxicology ; 72: 114-124, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30826346

RESUMO

Domoic acid (DA) is an excitatory neurotoxin produced by marine algae and responsible for Amnesiac Shellfish Poisoning in humans. Current regulatory limits (˜0.075-0.1 mg/kg/day) protect against acute toxicity, but recent studies suggest that the chronic consumption of DA below the regulatory limit may produce subtle neurotoxicity in adults, including decrements in memory. As DA-algal blooms are increasing in both severity and frequency, we sought to better understand the effects of chronic DA exposure on reproductive and neurobehavioral endpoints in a preclinical nonhuman primate model. To this end, we initiated a long-term study using adult, female Macaca fascicularis monkeys exposed to daily, oral doses of 0.075 or 0.15 mg/kg of DA for a range of 321-381, and 346-554 days, respectively. This time period included a pre-pregnancy, pregnancy, and postpartum period. Throughout these times, trained data collectors observed intentional tremors in some exposed animals during biweekly clinical examinations. The present study explores the basis of this neurobehavioral finding with in vivo imaging techniques, including diffusion tensor magnetic resonance imaging and spectroscopy. Diffusion tensor analyses revealed that, while DA exposed macaques did not significantly differ from controls, increases in DA-related tremors were negatively correlated with fractional anisotropy, a measure of structural integrity, in the internal capsule, fornix, pons, and corpus callosum. Brain concentrations of lactate, a neurochemical closely linked with astrocytes, were also weakly, but positively associated with tremors. These findings are the first documented results suggesting that chronic oral exposure to DA at concentrations near the current human regulatory limit are related to structural and chemical changes in the adult primate brain.


Assuntos
Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Ácido Caínico/análogos & derivados , Toxinas Marinhas/toxicidade , Neurotoxinas/toxicidade , Animais , Imagem de Tensor de Difusão , Feminino , Ácido Caínico/administração & dosagem , Ácido Caínico/toxicidade , Macaca fascicularis , Toxinas Marinhas/administração & dosagem , Neurotoxinas/administração & dosagem , Período Pós-Parto , Gravidez , Tremor/induzido quimicamente
8.
Neuroscience ; 406: 86-96, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30858108

RESUMO

Activated microglia have two functional states (M1 and M2) which play dual roles in neurodegenerative diseases. In the present study, we explored a possible neuroprotective function of M2 microglia against kainic acid (KA)-induced neurodegeneration in primary neurons co-cultured with different microglial populations. Neurons were isolated from the hippocampi and cortices of C57BL/6 embryos (embryonic day 16) and microglia were extracted from neonatal pups (postnatal days 0-2). Microglia were either unstimulated (M0-phenotype) or stimulated with lipopolysaccharide and interferon-γ to form the M1-phenotype, or with interleukin (IL)-4, IL-10, and transforming growth factor -ß for the M2-phenotype. Neurons were co-cultured with each of the three microglial phenotypes and treated with KA for 24 h. Next, we analyzed the cell survival rate, nitric oxide (NO) levels, and lactate dehydrogenase production, cytokines levels, and expression of nuclear factor κB (NF-κB) and caspase 3 among the three groups before and after KA insult. Our results indicated that M2 microglia played a neuroprotective role in KA-induced neurotoxicity, as demonstrated by high neuronal survival as well as decreased production of NO and pro-inflammatory cytokines. In contrast, neurons co-cultured with M1 microglia exhibited the lowest survival rate as well as increased levels of NO and pro-inflammatory cytokines. Further, the expression of NF-κB and caspase 3 were significantly decreased in M2 microglia co-cultures compared to M1 or M0 microglia co-cultures after KA insult. Therefore, M2 microglia may exert a neuroprotective function in KA-induced neurotoxicity via the down-regulation of NF-κB and caspase 3 signaling pathways.


Assuntos
Caspase 3/metabolismo , Ácido Caínico/toxicidade , Microglia/metabolismo , NF-kappa B/metabolismo , Neuroproteção/fisiologia , Transdução de Sinais/fisiologia , Animais , Animais Recém-Nascidos , Células Cultivadas , Técnicas de Cocultura , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Microglia/efeitos dos fármacos , Neuroproteção/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
9.
Neurotoxicology ; 72: 101-106, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30772382

RESUMO

BACKGROUND: Neural cell adhesion molecule (NCAM) belongs to the immunoglobulin superfamily of adhesion molecules. Polysialic acid (PSA) is attached to NCAM post-translationally. PSA residues are considered to reduce the adhesive properties of NCAM and play an important role in the regulation of cell interactions. PSA-NCAM is largely expressed in the mature retina by glial cells adjacent to retinal ganglion cells (RGCs) but its functions remain unclear. The objective of this study was to explore the role of PSA-NCAM with respect to RGC survival following kainic acid (KA)-induced excitotoxicity. METHODS: Experiments were performed on C57BL/6NTac male mice. KA was injected intravitreally to induce RGC damage. RGCs were visualized using an anti-Brn3a antibody. Endoneuraminidase N (NA) was administrated intravitreally to cleave PSA chains from NCAM. RESULTS: KA induced an 80% reduction in the density of RGCs that was accompanied by a decrease in PSA-NCAM in the RGC layer. KA treatment induced a pronounced increase in the level of matrix metalloproteinase-9 (MMP-9) in the inner layers of the retina. Inhibition of MMP-9 reduced both RGC death and PSA-NCAM shedding in the retina. PSA-NCAM cleavage induced by NA abolished the protective action of the MMP-9 inhibitor and decreased RGC survival following KA-treatment. CONCLUSIONS: A decrease in retinal PSA-NCAM levels following KA administration is due to the induction of active MMP-9, which removes extracellular PSA-NCAM from the surface of astroglial and Müller cells. The MMP-9 induced shedding of PSA-NCAM enhances KA-induced toxicity and at least in part contributes to the observed loss of RGCs following excitotoxic damage.


Assuntos
Agonistas de Aminoácidos Excitatórios/toxicidade , Ácido Caínico/toxicidade , Molécula L1 de Adesão de Célula Nervosa/metabolismo , Células Ganglionares da Retina/efeitos dos fármacos , Células Ganglionares da Retina/metabolismo , Ácidos Siálicos/metabolismo , Animais , Contagem de Células , Sobrevivência Celular/efeitos dos fármacos , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Camundongos Endogâmicos C57BL
10.
Toxins (Basel) ; 11(2)2019 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-30736356

RESUMO

Some species of the genus Pseudo-nitzschia produce the toxin domoic acid, which causes amnesic shellfish poisoning (ASP). Given that bivalve mollusks are filter feeders, they can accumulate these toxins in their tissues. To elucidate the transcriptional response of the queen scallop Aequipecten opercularis after exposure to domoic acid-producing Pseudo-nitzschia, the digestive gland transcriptome was de novo assembled using an Illumina HiSeq 2000 platform. Then, a differential gene expression analysis was performed. After the assembly, 142,137 unigenes were obtained, and a total of 10,144 genes were differentially expressed in the groups exposed to the toxin. Functional enrichment analysis found that 374 Pfam (protein families database) domains were significantly enriched. The C1q domain, the C-type lectin, the major facilitator superfamily, the immunoglobulin domain, and the cytochrome P450 were among the most enriched Pfam domains. Protein network analysis showed a small number of highly connected nodes involved in specific functions: proteasome components, mitochondrial ribosomal proteins, protein translocases of mitochondrial membranes, cytochromes P450, and glutathione S-transferases. The results suggest that exposure to domoic acid-producing organisms causes oxidative stress and mitochondrial dysfunction. The transcriptional response counteracts these effects with the up-regulation of genes coding for some mitochondrial proteins, proteasome components, and antioxidant enzymes (glutathione S-transferases, thioredoxins, glutaredoxins, and copper/zinc superoxide dismutases).


Assuntos
Trato Gastrointestinal/efeitos dos fármacos , Ácido Caínico/análogos & derivados , Toxinas Marinhas/toxicidade , Pectinidae/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos , Animais , Diatomáceas , Trato Gastrointestinal/metabolismo , Ácido Caínico/toxicidade , Pectinidae/genética
11.
Tissue Cell ; 56: 31-40, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30736902

RESUMO

After injury of the nervous system glial cells react according to the stimuli by modifying their morphology and function. Glia activation was reported in different kainic acid (KA)-induced neurodegeneration models. Here, we describe glial morphometric changes occurring in an excitotoxic KA-induced cervical spinal cord injury model. Concomitant degenerative and apoptotic processes are also reported. Male rats injected at the spinal cord C5 segment either with KA or saline were euthanized at post-injection (PI) days 1, 2, 3 or 7. Anti-IBA-1 and anti-GFAP antibodies were used to identify microglia and activated astrocytes, respectively, and to morphometrically characterized them. Fluoro-Jade B staining and TUNEL reaction were used to determine neuronal and glial degeneration and apoptosis. KA-injected group showed a significant increase in microglia number at the ipsilateral side by PI day 3. Different microglia reactive phenotypes were observed. Reactive microglia was still present by PI day 7. Astrocytes in KA-injected group showed a biphasic increase in number at PI days 1 and 3. Degenerative and apoptotic events were only observed in KA-injected animals, increasing mainly by PI day 1. Understanding the compromise of glia in different neurodegenerative processes may help to define possible common or specific therapeutic approaches directed towards neurorestorative strategies.


Assuntos
Anticorpos Anti-Idiotípicos/administração & dosagem , Proteína Glial Fibrilar Ácida/imunologia , Degeneração Neural/tratamento farmacológico , Traumatismos da Medula Espinal/tratamento farmacológico , Animais , Anticorpos Anti-Idiotípicos/imunologia , Apoptose/efeitos dos fármacos , Astrócitos/efeitos dos fármacos , Astrócitos/patologia , Proteína Glial Fibrilar Ácida/antagonistas & inibidores , Ácido Caínico/toxicidade , Microglia/efeitos dos fármacos , Microglia/imunologia , Microglia/patologia , Degeneração Neural/induzido quimicamente , Degeneração Neural/imunologia , Neuroglia/efeitos dos fármacos , Neuroglia/imunologia , Neurônios/efeitos dos fármacos , Neurônios/imunologia , Neurônios/patologia , Ratos , Medula Espinal/efeitos dos fármacos , Medula Espinal/imunologia , Medula Espinal/patologia , Traumatismos da Medula Espinal/induzido quimicamente , Traumatismos da Medula Espinal/imunologia , Traumatismos da Medula Espinal/patologia
12.
Neuroreport ; 30(5): 358-362, 2019 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-30724852

RESUMO

Epilepsy is a neurological disorder of the central nervous system characterized by hypersynchronized neuronal activity and has been associated with oxidative stress. Oxidative stress interferes with the expression of genes as well as transcriptional factors such as nuclear factor-erythroid 2-related factor 2 (Nrf2). We evaluated the expression of Nrf2 in the rat brain in treated with kainic acid (KA) and pentylenetetrazole (PTZ). Nrf2 immunoreactivity was observed in astrocytes of the hippocampal region in rats exposed at KA. Nrf2 expression was increased significantly in rats with KA and PTZ. These results provide evidence that the increased expression of Nrf2 is part of the mechanism against KA and PTZ toxicity.


Assuntos
Encéfalo/metabolismo , Convulsivantes/toxicidade , Ácido Caínico/toxicidade , Fator 2 Relacionado a NF-E2/biossíntese , Pentilenotetrazol/toxicidade , Animais , Encéfalo/efeitos dos fármacos , Epilepsia/induzido quimicamente , Epilepsia/metabolismo , Masculino , Estresse Oxidativo/fisiologia , Ratos , Ratos Wistar
13.
Turk Neurosurg ; 29(4): 478-485, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30649800

RESUMO

AIM: To compare neurodegenerative changes using the Fluoro-Jade B staining, following status epilepticus induced by intraamygdaloid injection of kainic acid in Genetic Absence Epilepsy Rats from Strasbourg (GAERS) and non-epileptic control Wistar rats. MATERIAL AND METHODS: A single unilateral intra-amygdaloid kainic acid (750 ng) was administered in adult male GAERS and Wistar rats to induce status epilepticus. We recorded electroencephalogram (EEG) and behavioral changes throughout the experiments. After 1 week of the kainic acid injection, rats were sacrificed, and the brains were removed. We obtained 20λm sections and processed them for Fluoro-Jade B and Nissl staining, which were evaluated semi-quantitatively. RESULTS: Following kainic acid injections, status epilepticus developed in all rats. In GAERS rats, motor seizures were considerably delayed, with no statistically significant difference in the number of seizures. However, statistically significant differences were observed in the Fluoro-Jade B staining in GAERS rats between contralateral and ipsilateral sides of the CA3, CA1, somatosensory cortex, entorhinal cortex, piriform cortex, reticular nucleus, putamen, and claustrum. In Wistar rats, the CA3, CA1, somatosensory cortex, entorhinal cortex, piriform cortex, reticular nucleus, amygdala, and laterodorsal nucleus exhibited significant differences. Comparing GAERS and Wistar rats, a statistically significant difference was observed for both sides of CA1. In both groups, the staining was prominent ipsilaterally, except for the claustrum in GAERS rats. However, the motor cortex remained unaffected in both groups. Neurodegenerative changes were not associated with the severity of seizures in both groups following the intra-amygdaloid kainic acid administration. CONCLUSION: This study demonstrates that CA1 is the only region exhibiting a statistically significant difference between Wistar and GAERS rats.


Assuntos
Região CA1 Hipocampal/efeitos dos fármacos , Região CA1 Hipocampal/patologia , Ácido Caínico/toxicidade , Doenças Neurodegenerativas/induzido quimicamente , Doenças Neurodegenerativas/patologia , Tonsila do Cerebelo/efeitos dos fármacos , Tonsila do Cerebelo/patologia , Animais , Modelos Animais de Doenças , Eletroencefalografia/efeitos dos fármacos , Eletroencefalografia/métodos , Epilepsia Tipo Ausência/genética , Epilepsia Tipo Ausência/patologia , Agonistas de Aminoácidos Excitatórios/toxicidade , Masculino , Doenças Neurodegenerativas/genética , Ratos , Ratos Wistar , Especificidade da Espécie
14.
Epilepsy Res ; 151: 1-6, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30669043

RESUMO

Lycopene (LCP) is a carotenoid that protects against many diseases by alleviating oxidative stress. However, the effect of LCP on epileptic seizures has not been examined well in previous studies. In the current work, we employed kainic acid (KA) to induce experimental epileptic seizures in mice, and investigated the function of LCP during this process. We found that the onset and extent of KA-induced seizures were alleviated in LCP-pretreated mice. Nissl staining of hippocampus showed that the granule cell dispersion lesion induced by KA was improved by the LCP treatment. Additionally, we analyzed the oxidative stress levels in mice and found that LCP elevated SOD activity and suppressed MDA level in KA-induced seizures. Moreover, the expression of GABA receptors was influenced by LCP treatment. LCP suppressed the upregulation of gabrb2 and gabrb3 induced by KA, whereas it enhanced the expression of gabrb1. Results suggested that LCP plays a protective function in KA-induced seizures. Hence, it may be a potential functional food alternative for controlling and treating epileptic seizures.


Assuntos
Antioxidantes/administração & dosagem , Licopeno/administração & dosagem , Convulsões/prevenção & controle , Animais , Piscadela/efeitos dos fármacos , Modelos Animais de Doenças , Esquema de Medicação , Agonistas de Aminoácidos Excitatórios/toxicidade , Expressão Gênica/efeitos dos fármacos , Glutationa/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Ácido Caínico/toxicidade , Malondialdeído , Camundongos , RNA Mensageiro/metabolismo , Receptores de GABA/genética , Receptores de GABA/metabolismo , Convulsões/induzido quimicamente , Convulsões/patologia , Comportamento Estereotipado/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Fatores de Tempo
15.
Brain Pathol ; 29(1): 28-44, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29665128

RESUMO

Kainic acid, an analogue of the excitatory neurotransmitter glutamate, can trigger seizures and neurotoxicity in the hippocampus and other limbic structures in a manner that mirrors the neuropathology of human temporal lobe epilepsy (TLE). However, the underlying mechanisms associated with the neurotoxicity remain unclear. Since amyloid-ß (Aß) peptides, which are critical in the development of Alzheimer's disease, can mediate toxicity by activating glutamatergic NMDA receptors, it is likely that the enhanced glutamatergic transmission that renders hippocampal neurons vulnerable to kainic acid treatment may involve Aß peptides. Thus, we seek to establish what role Aß plays in kainic acid-induced toxicity using in vivo and in vitro paradigms. Our results show that systemic injection of kainic acid to adult rats triggers seizures, gliosis and loss of hippocampal neurons, along with increased levels/processing of amyloid precursor protein (APP), resulting in the enhanced production of Aß-related peptides. The changes in APP levels/processing were evident primarily in activated astrocytes, implying a role for astrocytic Aß in kainic acid-induced toxicity. Accordingly, we showed that treating rat primary cultured astrocytes with kainic acid can lead to increased Aß production/secretion without any compromise in cell viability. Additionally, we revealed that kainic acid reduces neuronal viability more in neuronal/astrocyte co-cultures than in pure neuronal culture, and this is attenuated by precluding Aß production. Collectively, these results indicate that increased production/secretion of Aß-related peptides from activated astrocytes can contribute to neurotoxicity in kainic acid-treated rats. Since kainic acid administration can lead to neuropathological changes resembling TLE, it is likely that APP/Aß peptides derived from astrocytes may have a role in TLE pathogenesis.


Assuntos
Peptídeos beta-Amiloides/fisiologia , Epilepsia do Lobo Temporal/fisiopatologia , Neurônios/efeitos dos fármacos , Doença de Alzheimer/patologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Astrócitos/metabolismo , Astrócitos/fisiologia , Encéfalo/patologia , Células Cultivadas , Modelos Animais de Doenças , Hipocampo/patologia , Humanos , Ácido Caínico/farmacologia , Ácido Caínico/toxicidade , Masculino , Doenças Neurodegenerativas/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Fragmentos de Peptídeos/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos
16.
Neurosci Lett ; 694: 116-123, 2019 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-30500398

RESUMO

Neuroprotective effects of short prolactin (PRL) pre-treatment against kainic acid (KA)-induced damage include neuron loss avoidance in all hippocampal regions and attenuation of seizures. Recent evidence points PRL receptor (PRL-R) as mediator of such neuroprotective effects and seizures as regulators of neuronal marker transcript expression in the hippocampus. Here, we investigated if a daily PRL dose of 100 µg or vehicle for 14 days in ovariectomized rats (OVX) prevents neuron loss induced by KA administered on the third day of PRL treatment in a systemic single dose of 7.5 mg/kg or vehicle, and promotes PRL-R, vesicular glutamate transporter 1 (VGLUT1) and glutamic acid decarboxylase 65 (GAD65) expression changes in the hippocampus of sacrificed rats 27 days after the KA administration. Immunostaining for Neu-N and PRL-R revealed significant neuron number and PRL-R expression reduction induced by KA that was prevented and turned into overexpression respectively in all hippocampal regions when PRL was added; while VGLUT1,and GAD65 immunostaining displayed expression decrease in the CA1 of injured rats, prevented in the last case and turned into VGLUT1, overexpression when administered PRL. These data indicate that chronic PRL administration before damage induces hippocampal neuroprotection associated with PRL-R and VGLUT1 overexpression, the latter in a regiondependent way.


Assuntos
Hipocampo/efeitos dos fármacos , Ácido Caínico/toxicidade , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/administração & dosagem , Prolactina/administração & dosagem , Receptores da Prolactina/metabolismo , Proteína Vesicular 1 de Transporte de Glutamato/metabolismo , Animais , Agonistas de Aminoácidos Excitatórios/toxicidade , Feminino , Glutamato Descarboxilase/metabolismo , Hipocampo/metabolismo , Hipocampo/patologia , Neurônios/metabolismo , Ratos
17.
Mol Neurobiol ; 56(7): 5095-5110, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30484111

RESUMO

Kainic acid (KA) is an analogue of the excitatory neurotransmitter glutamate that, when injected systemically into adult rats, can trigger seizures and progressive neuronal loss in a manner that mirrors the neuropathology of human mesial temporal lobe epilepsy. However, biomolecular mechanisms responsible for the neuronal loss that occurs as a consequence of this treatment remains elusive. We have recently reported that toxicity induced by KA can partly be mediated by astrocyte-derived amyloid ß (Aß) peptides, which are critical in the development of Alzheimer's disease (AD). Nonetheless, little is known how KA can influence amyloid precursor protein (APP) levels and processing in astrocytes. Thus, in the present study using human U-373 astrocytoma and rat primary astrocytes, we evaluated the role of KA on APP metabolism. Our results revealed that KA treatment increased the levels of APP and its cleaved products (α-/ß-CTFs) in cultured U-373 astrocytoma and primary astrocytes, without altering the cell viability. The cellular and secretory levels of Aß1-40/Aß1-42 were markedly increased in KA-treated astrocytes. We also demonstrated that the steady-state levels of APP-secretases were not altered but the activity of γ-secretase is enhanced in KA-treated U-373 astrocytoma. Furthermore, using selective receptor antagonists, we showed that the effects of KA is mediated by activation of kainate receptors and not NMDA or AMPA receptors. These results suggest that KA can enhance amyloidogenic processing of APP by activating its own receptor leading to increased production/secretion of Aß-related peptides from activated astrocytes which may contribute to the pathogenesis of temporal lobe epilepsy.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Ácido Caínico/farmacologia , Receptores de Ácido Caínico/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Humanos , Ácido Caínico/toxicidade , Receptores de Ácido Caínico/agonistas
18.
Epilepsy Res ; 149: 107-116, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30584976

RESUMO

OBJECTIVES: The hippocampus is susceptible to damage in patients with epilepsy and in animals with seizures caused by excitotoxic agents. The effect of vitamin D on hippocampal apoptosis related with seizures has not been reported. However, epileptic patients have an increased risk of hypovitaminosis D which is most likely due to the effects of antiepileptic drugs. Therefore, in this study, it was aimed to evaluate the effects of vitamin D on hippocampal apoptosis related with seizures by using pentylenetetrazol (PTZ) and kainic acid (KA) in rats. METHODS: Male Sprague Dawley rats, aged 5.5 weeks, were randomly divided into six groups: control, vitamin D, PTZ, KA, PTZ + vitamin D and KA + vitamin D groups. The groups that received vitamin D were given 500 IU/kg of vitamin D daily for two weeks in addition to a standard diet. At the end of this period, PTZ and KA were applied to trigger seizures in the rats in the seizure groups. 24 h after the administration of PTZ and KA, the rats were decapitated. In the hippocampal region, apoptosis was assessed by TUNEL and brain-derived neurotrophic factor (BDNF), Bax, caspase-3 and c-fos activation were evaluated by immunohistochemical method. RESULTS: BDNF level increased while c-fos, Bax and caspase-3 levels decreased (p < 0.0001, in all) in the hippocampal neurons of the groups that were pre-treated with vitamin D before the administration of PTZ and KA, in comparison with the PTZ and KA groups. Vitamin D significantly decreased the number of apoptotic cells in these rats in comparison with the PTZ and KA groups (p < 0.0001). CONCLUSION: This study indicates that vitamin D has neuroprotective effects on hippocampal apoptosis induced by PTZ and KA in rats. With this study it is suggested that keeping vitamin D levels within normal limits may be beneficial for patients with epilepsy, especially children.


Assuntos
Apoptose/efeitos dos fármacos , Hipocampo/patologia , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/uso terapêutico , Convulsões/patologia , Vitamina D/uso terapêutico , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Caspase 3/metabolismo , Convulsivantes/toxicidade , Modelos Animais de Doenças , Marcação In Situ das Extremidades Cortadas , Ácido Caínico/toxicidade , Masculino , Fármacos Neuroprotetores/farmacologia , Pentilenotetrazol/toxicidade , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos , Ratos Sprague-Dawley , Convulsões/induzido quimicamente , Convulsões/tratamento farmacológico , Proteína X Associada a bcl-2/metabolismo
19.
Toxicon ; 156: 66-71, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30448286

RESUMO

Domoic acid (DA) is a neurotoxin naturally produced by Pseudo-nitzschia diatoms that may be transferred through the marine food web and cause mass mortality events at higher trophic levels. Yet, the effects of the dissolved marine toxin on foraging responses and swimming performances of fish early stages are poorly known. Here we evaluated the effects of short-term exposure (24 h) to a single dose of domoic acid (136 µg DA L-1) on larvae (15-20 days post-hatch) of three commercially important fish species (the sea breams Diplodus sargus and Sparus aurata and the meagre Argyrosomus regius). Although DA exposure did not elicit significant effects on larval survival (p > 0.05) and swimming performance (p > 0.05), the toxin significantly affected the fish capture success (p < 0.001). Our findings suggest that toxigenic Pseudo-nitzschia blooms may compromise fish early stages, in particular larvae feeding behaviours, leading to complications in the development and increasing fish vulnerability and mortality.


Assuntos
Comportamento Alimentar/efeitos dos fármacos , Ácido Caínico/análogos & derivados , Perciformes/fisiologia , Dourada/fisiologia , Natação , Animais , Diatomáceas , Ácido Caínico/toxicidade , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Toxinas Marinhas/toxicidade , Perciformes/crescimento & desenvolvimento , Dourada/crescimento & desenvolvimento , Análise de Sobrevida
20.
Harmful Algae ; 79: 50-52, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30420015

RESUMO

Copepods are important grazers on toxic phytoplankton and serve as vectors for algal toxins up the marine food web. Success of phytoplankton depends among other factors on protection against grazers like copepods, and same way copepod survival and population resilience relies on their ability to escape predators. Little is, however, known about the effect of toxins on the escape response of copepods. In this study we experimentally tested the hypothesis that the neurotoxin domoic acid (DA) produced by the diatom Pseudo-nitzschia affects escape responses of planktonic copepods. We found that the arctic copepods Calanus hyperboreus and C. glacialis reduced their escape response after feeding on a DA-producing diatom. The two species were not affected the same way; C. hyperboreus was affected after shorter exposure and less intake of DA. The negative effect on escape response was not related to the amount of DA accumulated in the copepods. Our results suggest that further research on the effects of DA on copepod behavior and DA toxicity mechanisms is required to evaluate the anti-grazing function of DA.


Assuntos
Copépodes/fisiologia , Diatomáceas/química , Reação de Fuga/efeitos dos fármacos , Ácido Caínico/análogos & derivados , Neurotoxinas/toxicidade , Animais , Copépodes/efeitos dos fármacos , Cadeia Alimentar , Ácido Caínico/toxicidade , Fitoplâncton
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