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1.
Mol Neurobiol ; 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38696064

RESUMO

Iron accumulation has been associated with the pathogenesis of neurodegenerative diseases and memory decline. As previously described by our research group, iron overload in the neonatal period induces persistent memory deficits and increases oxidative stress and apoptotic markers. The neuronal insult caused by iron excess generates an energetic imbalance that can alter glutamate concentrations and thus trigger excitotoxicity. Drugs that block glutamatergic receptor eligibly mitigate neurotoxicity; among them is perampanel (PER), a reversible AMPA receptor (AMPAR) antagonist. In the present study, we sought to investigate the neuroprotective effects of PER in rats subjected to iron overload in the neonatal period. Recognition and aversive memory were evaluated, AMPAR subunit phosphorylation, as well as the relative expression of genes such as GRIA1, GRIA2, DLG4, and CAC, which code proteins involved in AMPAR anchoring. Male rats received vehicle or carbonyl iron (30 mg/kg) from the 12th to the 14th postnatal day and were treated with vehicle or PER (2 mg/kg) for 21 days in adulthood. The excess of iron caused recognition memory deficits and impaired emotional memory, and PER was able to improve the rodents' memory. Iron increased the phosphorylation of GLUA1 subunit, which was reversed by PER. Furthermore, iron overload increased the expression of the GRIA1 gene and decreased the expression of the DLG4 gene, demonstrating the influence of metal accumulation on the metabolism of AMPAR. These results suggest that iron can interfere with AMPAR functionality, through altered phosphorylation of its subunits, and the expression of genes that code for proteins critically involved in the assembly and anchoring of AMPAR. The blockade of AMPAR with PER is capable of partially reversing the cognitive deficits caused by iron overload.

2.
Eur J Nutr ; 63(4): 1163-1175, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38358514

RESUMO

PURPOSE: The present study aimed at evaluating possible synergistic effects between two risk factors for cognitive decline and neurodegenerative disorders, i.e. iron overload and exposure to a hypercaloric/hyperlipidic diet, on cognition, insulin resistance, and hippocampal GLUT1, GLUT3, Insr mRNA expression, and AKT phosporylation. METHODS: Male Wistar rats were treated with iron (30 mg/kg carbonyl iron) or vehicle (5% sorbitol in water) from 12 to 14th post-natal days. Iron-treated rats received a standard laboratory diet or a high fat diet from weaning to adulthood (9 months of age). Recognition and emotional memory, peripheral blood glucose and insulin levels were evaluated. Glucose transporters (GLUT 1 and GLUT3) and insulin signaling were analyzed in the hippocampus of rats. RESULTS: Both iron overload and exposure to a high fat diet induced memory deficits. Remarkably, the association of iron with the high fat diet induced more severe cognitive deficits. Iron overload in the neonatal period induced higher insulin levels associated with significantly higher HOMA-IR, an index of insulin resistance. Long-term exposure to a high fat diet resulted in higher fasting glucose levels. Iron treatment induced changes in Insr and GLUT1 expression in the hippocampus. At the level of intracellular signaling, both iron treatment and the high fat diet decreased AKT phosphorylation. CONCLUSION: The combination of iron overload with exposure to a high fat diet only led to synergistic deleterious effect on emotional memory, while the effects induced by iron and by the high fat diet on AKT phosphorylation were comparable. These findings indicate that there is, at least to some extent, an additive effect of iron combined with the diet. Further studies investigating the mechanisms associated to deleterious effects on cognition and susceptibility for the development of age-associated neurodegenerative disorders are warranted.


Assuntos
Animais Recém-Nascidos , Dieta Hiperlipídica , Transportador de Glucose Tipo 1 , Hipocampo , Resistência à Insulina , Sobrecarga de Ferro , Transtornos da Memória , Ratos Wistar , Animais , Masculino , Dieta Hiperlipídica/efeitos adversos , Sobrecarga de Ferro/complicações , Sobrecarga de Ferro/metabolismo , Transtornos da Memória/etiologia , Hipocampo/metabolismo , Hipocampo/efeitos dos fármacos , Ratos , Transportador de Glucose Tipo 1/metabolismo , Transportador de Glucose Tipo 1/genética , Transportador de Glucose Tipo 3/metabolismo , Transportador de Glucose Tipo 3/genética , Receptor de Insulina/metabolismo , Receptor de Insulina/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Glicemia/metabolismo , Insulina/sangue , Transdução de Sinais
4.
Behav Brain Res ; 417: 113555, 2022 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-34450240

RESUMO

Clinical and preclinical evidence has indicated that estrogen depletion leads to memory impairments and increases the susceptibility to neural damage. Here, we have sought to investigate the effects of Cannabidiol (CBD) a non-psychotomimetic compound from Cannabis sativa, on memory deficits induced by estrogen depletion in rats, and its underlying mechanisms. Adult rats were subjected to bilateral ovariectomy, an established estrogen depletion model in rodents, or sham surgery and allowed to recover for three weeks. After that, they received daily injections of CBD (10 mg/kg) for fourteen days. Rats were tested in the inhibitory avoidance task, a type of emotionally-motivated memory. After behavioral testing they were euthanized, and their hippocampi were isolated for analysis of components of the Akt/GSK3ß survival pathway and the antiapoptotic protein Bcl2. Results revealed that ovariectomy impaired avoidance memory, and CBD was able to completely reverse estrogen depletion-induced memory impairment. Ovariectomy also reduced Akt/GSK3ß pathway's activation by decreasing the phosphorylation levels of Akt and GSK3ß and Bcl2 levels, which were ameliorated by CBD. The present results indicate that CBD leads to a functional recovery accompanied by the Akt/GSK3ß survival pathway's activation, supporting its potential as a treatment for estrogen decline-induced deterioration of neural functioning and maintenance.


Assuntos
Comportamento Animal/efeitos dos fármacos , Canabidiol/farmacologia , Estrogênios/deficiência , Glicogênio Sintase Quinase 3 beta/efeitos dos fármacos , Transtornos da Memória/tratamento farmacológico , Proteínas Proto-Oncogênicas c-akt/efeitos dos fármacos , Animais , Encéfalo/metabolismo , Feminino , Glicogênio Sintase Quinase 3 beta/metabolismo , Hipocampo/metabolismo , Modelos Teóricos , Ovariectomia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Transdução de Sinais
5.
Neurobiol Learn Mem ; 184: 107499, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34352396

RESUMO

Estrogens, particularly 17ß-estradiol (estradiol, E2), regulate memory formation. E2 acts through its intracellular receptors, estrogen receptors (ER) ERα and ERß, as well as a recently identified G protein-coupled estrogen receptor (GPER). Although the effects of E2 on memory have been investigated, studies examining the effects of GPER stimulation are scarce. Selective GPER agonism improves memory in ovariectomized female rats, but little information is available regarding the effects of GPER stimulation in male rodents. The aim of the present study was to investigate the effects of the GPER agonist, G1, on consolidation and reconsolidation of inhibitory avoidance (IA) and object recognition (OR) memory in male rats. Animals received vehicle, G1 (15, 75, 150 µg/kg; i.p.), or the GPER antagonist G15 (100 µg/kg; i.p.) immediately after training, or G1 (150 µg/kg; i.p.) 3 or 6 h after training. To investigate reconsolidation, G1 was administered immediately after IA retention Test 1. Results indicated that G1 administered immediately after training at the highest dose enhanced both OR and IA memory consolidation, while GPER blockade immediately after training impaired OR. No effects of GPER stimulation were observed when G1 was given 3 or 6 h after training or after Test 1. The present findings provide evidence that GPER is involved in the early stages of memory consolidation in both neutral and emotional memory tasks in male adult rats.


Assuntos
Memória/fisiologia , Receptores Acoplados a Proteínas G/fisiologia , Reconhecimento Psicológico/fisiologia , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Aprendizagem da Esquiva/fisiologia , Antagonistas do Receptor de Estrogênio/farmacologia , Estrogênios/farmacologia , Masculino , Memória/efeitos dos fármacos , Motivação/fisiologia , Ratos , Ratos Wistar , Receptores Acoplados a Proteínas G/efeitos dos fármacos , Reconhecimento Psicológico/efeitos dos fármacos
6.
Eur J Nutr ; 60(7): 3679-3690, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33738535

RESUMO

PURPOSE: To investigate the effects of lipoic acid (LA) supplementation during adulthood combined with supplementation later in life or LA administration only at old age on age-induced cognitive dysfunction, mitochondrial DNA deletions, caspase 3 and antioxidant response enzymes expression in iron-treated rats. METHODS: Male rats were submitted to iron treatment (30 mg/kg body wt of Carbonyl iron) from 12 to 14th post-natal days. Iron-treated rats received LA supplementation (50 mg/kg, daily) in adulthood and old age or at old age only for 21 days. Memory, mitochondrial DNA (mtDNA) complex I deletions, caspase 3 mRNA expression and antioxidant response enzymes mRNA expression were analyzed in the hippocampus. RESULTS: LA administration in adulthood combined with treatment later in life was able to reverse age-induced effects on object recognition and inhibitory avoidance memory, as well as on mtDNA deletions, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) expression, and antioxidant enzymes disruption induced by iron in aged rats. LA treatment only at old age reversed iron-induced effects to a lesser extent when compared to the combined treatment. CONCLUSION: The present findings support the view that LA supplementation may be considered as an adjuvant against mitochondrial damage and cognitive decline related to aging and neurodegenerative disorders.


Assuntos
Ácido Tióctico , Animais , Antioxidantes , DNA Mitocondrial , Suplementos Nutricionais , Ferro , Masculino , Ratos
7.
Mol Neurobiol ; 57(2): 1044-1054, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31664701

RESUMO

Over the years, iron accumulation in specific brain regions has been observed in normal aging and related to the pathogenesis of neurodegenerative disorders. Many neurodegenerative diseases may involve cognitive dysfunction, and we have previously shown that neonatal iron overload induces permanent cognitive deficits in adult rats and exacerbates age-associated memory decline. Autophagy is a catabolic pathway involved in the removal of toxic protein aggregates, which are a hallmark of neurodegenerative events. In the present study, we investigated whether iron accumulation would interfere with autophagy and also sought to determine the effects of rapamycin-induced stimulation of autophagy in attenuating iron-related cognitive deficits. Male Wistar rats received a single daily oral dose of vehicle or iron carbonyl (30 mg/kg) at postnatal days 12-14. In adulthood, they received daily intraperitoneal injections of vehicle or rapamycin (0.25 mg/kg) for 14 days. Results showed that iron given in the neonatal period impaired inhibitory avoidance memory and induced a decrease in proteins critically involved in the autophagy pathway, Beclin-1 and LC3, in the hippocampus. Rapamycin in the adulthood reversed iron-induced memory deficits, decreased the ratio phospho-mTOR/total mTOR, and recovered LC3 II levels in iron-treated rats. Our results suggest that iron accumulation, as observed in neurodegenerative disorders, hinders autophagy, which might play a role in iron-induced neurotoxicity. Rapamycin, by inducing authophagy, was able to ameliorate iron-induced cognitive impairments. These findings support the use of rapamycin as a potential neuroprotective treatment against the cognitive decline associated to neurodegenerative disorders.


Assuntos
Autofagia/efeitos dos fármacos , Disfunção Cognitiva , Sobrecarga de Ferro/tratamento farmacológico , Ferro/efeitos adversos , Transtornos da Memória/tratamento farmacológico , Sirolimo/farmacologia , Animais , Disfunção Cognitiva/induzido quimicamente , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/metabolismo , Modelos Animais de Doenças , Feminino , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Ferro/metabolismo , Sobrecarga de Ferro/metabolismo , Transtornos da Memória/induzido quimicamente , Doenças Neurodegenerativas/metabolismo , Ratos Wistar
8.
J Neuroendocrinol ; 31(10): e12780, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31418949

RESUMO

Iron accumulation in the brain has been associated with neurodegenerative disorders, and imaging studies in humans indicate that iron content in brain regions correlates with poor performance in cognitive tasks. In rats, iron overload impairs memory retention in a variety of memory tasks. Although the effects of iron on cognition in rodents are extensively reported, no previous study has been conducted in female rats. The incidence of certain dementias, such as Alzheimer's disease, is higher in women after menopause compared to aged-matched men. The role of oestrogen depletion in memory deficits in menopausal women is still a matter of debate. The present study aimed to characterise the effects of iron overload on memory in female rats by investigating the effects of ovariectomy (OVX, an experimental model of oestrogen depletion) in rats submitted to iron overload, as well as examining the effects of G protein-coupled oestrogen receptor (GPER) agonism on memory impairments induced by iron and OVX. Female rats received iron (30 mg kg-1 , orally) or vehicle at postnatal days 12-14 and were submitted to OVX in adulthood. Results showed that either iron or OVX impaired memory for object placement and inhibitory avoidance. The selective GPER agonist G1, administered immediately after training, reversed both iron- and OVX-induced memory impairments. G1 effects were abolished by protein kinase A (PKA) inhibition, suggesting the involvement of the cAMP/PKA/CREB signalling pathway. The search for novel oestrogen agonists with positive effects on cognition may be promising for the development of treatments for memory disorders.


Assuntos
Ferro/efeitos adversos , Isoquinolinas/farmacologia , Transtornos da Memória/fisiopatologia , Ovariectomia/psicologia , Receptores de Estrogênio/fisiologia , Transdução de Sinais/fisiologia , Sulfonamidas/farmacologia , Animais , AMP Cíclico/fisiologia , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/fisiologia , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Estrogênios/farmacologia , Feminino , Masculino , Transtornos da Memória/induzido quimicamente , Ratos , Receptores de Estrogênio/efeitos dos fármacos
9.
Transl Psychiatry ; 8(1): 176, 2018 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-30177808

RESUMO

Iron accumulation in the brain has been recognized as a common feature of both normal aging and neurodegenerative diseases. Cognitive dysfunction has been associated to iron excess in brain regions in humans. We have previously described that iron overload leads to severe memory deficits, including spatial, recognition, and emotional memory impairments in adult rats. In the present study we investigated the effects of neonatal iron overload on proteins involved in apoptotic pathways, such as Caspase 8, Caspase 9, Caspase 3, Cytochrome c, APAF1, and PARP in the hippocampus of adult rats, in an attempt to establish a causative role of iron excess on cell death in the nervous system, leading to memory dysfunction. Cannabidiol (CBD), the main non-psychotropic component of Cannabis sativa, was examined as a potential drug to reverse iron-induced effects on the parameters analyzed. Male rats received vehicle or iron carbonyl (30 mg/kg) from the 12th to the 14th postnatal days and were treated with vehicle or CBD (10 mg/kg) for 14 days in adulthood. Iron increased Caspase 9, Cytochrome c, APAF1, Caspase 3 and cleaved PARP, without affecting cleaved Caspase 8 levels. CBD reversed iron-induced effects, recovering apoptotic proteins Caspase 9, APAF1, Caspase 3 and cleaved PARP to the levels found in controls. These results suggest that iron can trigger cell death pathways by inducing intrinsic apoptotic proteins. The reversal of iron-induced effects by CBD indicates that it has neuroprotective potential through its anti-apoptotic action.


Assuntos
Apoptose/efeitos dos fármacos , Canabidiol/farmacologia , Disfunção Cognitiva/tratamento farmacológico , Hipocampo/patologia , Sobrecarga de Ferro/fisiopatologia , Transtornos da Memória/prevenção & controle , Animais , Animais Recém-Nascidos , Disfunção Cognitiva/induzido quimicamente , Modelos Animais de Doenças , Hipocampo/efeitos dos fármacos , Ferro/toxicidade , Compostos de Ferro/toxicidade , Masculino , Transtornos da Memória/induzido quimicamente , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos
10.
Biometals ; 31(6): 927-940, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30117045

RESUMO

Brain-derived neurotrophic factor (BDNF) plays a key role in neural development and physiology, as well as in pathological states. Post-mortem studies demonstrate that BDNF is reduced in the brains of patients affected by neurodegenerative diseases. Iron accumulation has also been associated to the pathogenesis of neurodegenerative diseases. In rats, iron overload induces persistent memory deficits, increases oxidative stress and apoptotic markers, and decreases the expression of the synaptic marker, synaptophysin. Deferiprone (DFP) is an oral iron chelator used for the treatment of systemic iron overload disorders, and has recently been tested for Parkinson's disease. Here, we investigated the effects of iron overload on BDNF levels and on mRNA expression of genes encoding TrkB, p75NTR, catalase (CAT) and NQO1. We also aimed at investigating the effects of DFP on iron-induced impairments. Rats received iron or vehicle at postnatal days 12-14 and when adults, received chronic DFP or water (vehicle). Recognition memory was tested 19 days after the beginning of chelation therapy. BDNF measurements and expression analyses in the hippocampus were performed 24 h after the last day of DFP treatment. DFP restored memory and increased hippocampal BDNF levels, ameliorating iron-induced effects. Iron overload in the neonatal period reduced, while treatment with DFP was able to rescue, the expression of antioxidant enzymes CAT and NQO1.


Assuntos
Antioxidantes/farmacologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Deferiprona/farmacologia , Modelos Animais de Doenças , Quelantes de Ferro/farmacologia , Transtornos da Memória/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Animais , Antioxidantes/química , Fator Neurotrófico Derivado do Encéfalo/análise , Deferiprona/química , Feminino , Hipocampo/efeitos dos fármacos , Quelantes de Ferro/química , Ratos , Ratos Wistar
11.
Brain Res Bull ; 139: 1-8, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29374603

RESUMO

Evidence has demonstrated iron accumulation in specific brain regions of patients suffering from neurodegenerative disorders, and this metal has been recognized as a contributing factor for neurodegeneration. Using an experimental model of brain iron accumulation, we have shown that iron induces severe memory deficits that are accompanied by oxidative stress, increased apoptotic markers, and decreased synaptophysin in the hippocampus of rats. The present study aims to characterize iron loading effects as well as to determine the molecular targets of cannabidiol (CBD), the main non-psychomimetic compound of Cannabis sativa, on mitochondria. Rats received iron in the neonatal period and CBD for 14 days in adulthood. Iron induced mitochondrial DNA (mtDNA) deletions, decreased epigenetic modulation of mtDNA, mitochondrial ferritin levels, and succinate dehydrogenase activity. CBD rescued mitochondrial ferritin and epigenetic modulation of mtDNA, and restored succinate dehydrogenase activity in iron-treated rats. These findings provide new insights into molecular targets of iron neurotoxicity and give support for the use of CBD as a disease modifying agent in the treatment of neurodegenerative diseases.


Assuntos
Canabidiol/uso terapêutico , DNA Mitocondrial/metabolismo , Hipocampo/efeitos dos fármacos , Compostos Carbonílicos de Ferro/toxicidade , Mitocôndrias/efeitos dos fármacos , Doenças Neurodegenerativas/induzido quimicamente , Doenças Neurodegenerativas/tratamento farmacológico , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Animais , Animais Recém-Nascidos , Creatina Quinase/metabolismo , Metilação de DNA/efeitos dos fármacos , DNA Mitocondrial/genética , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , NADH Desidrogenase/genética , NADH Desidrogenase/metabolismo , Doenças Neurodegenerativas/patologia , Gravidez , Ratos , Ratos Wistar
12.
Mol Neurobiol ; 53(9): 6228-6239, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-26558634

RESUMO

Alterations of brain iron levels have been observed in a number of neurodegenerative disorders. We have previously demonstrated that iron overload in the neonatal period results in severe and persistent memory deficits in the adulthood. Protein degradation mediated by the ubiquitin-proteasome system (UPS) plays a central regulatory role in several cellular processes. Impairment of the UPS has been implicated in the pathogenesis of neurodegenerative disorders. Here, we examined the effects of iron exposure in the neonatal period (12th-14th day of postnatal life) on the expression of proteasome ß-1, ß-2, and ß-5 subunits, and ubiquitinated proteins in brains of 15-day-old rats, to evaluate the immediate effect of the treatment, and in adulthood to assess long-lasting effects. Two different memory types, emotionally motivated conditioning and object recognition were assessed in adult animals. We found that iron administered in the neonatal period impairs both emotionally motivated and recognition memory. Polyubiquitinated protein levels were increased in the hippocampus, but not in the cortex, of adult animals treated with iron. Gene expression of subunits ß1 and ß5 was affected by age, being higher in the early stages of development in the hippocampus, accompanied by an age-related increase in polyubiquitinated protein levels in adults. In the cortex, gene expression of the three proteasome subunits was significantly higher in adulthood than in the neonatal period. These findings suggest that expression of proteasome subunits and activity are age-dependently regulated. Iron exposure in the neonatal period produces long-lasting harmful effects on the UPS functioning, which may be related with iron-induced memory impairment.


Assuntos
Hipocampo/metabolismo , Ferro/farmacologia , Memória , Proteínas Ubiquitinadas/metabolismo , Animais , Animais Recém-Nascidos , Comportamento Animal/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Memória/efeitos dos fármacos , Poliubiquitina/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Ratos Wistar
13.
Neurobiol Learn Mem ; 120: 1-6, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25687693

RESUMO

Healthy neuronal function and synaptic modification require a concert of synthesis and degradation of proteins. Increasing evidence indicates that protein turnover mediated by proteasome activity is involved in long-term synaptic plasticity and memory. However, its role in different phases of memory remains debated, and previous studies have not examined the possible requirement of protein degradation in recognition memory. Here, we show that the proteasome inhibitor, lactacystin (LAC), infused into the CA1 area of the hippocampus at two specific time points during consolidation, impairs 24-retention of memory for object recognition in rats. Administration of LAC after retrieval did not affect retention. These findings provide the first evidence for a requirement of proteasome activity in recognition memory, indicate that protein degradation in the hippocampus is necessary during selective time windows of memory consolidation, and further our understanding of the role of protein turnover in memory formation.


Assuntos
Hipocampo/fisiologia , Consolidação da Memória/fisiologia , Complexo de Endopeptidases do Proteassoma/fisiologia , Reconhecimento Psicológico/fisiologia , Acetilcisteína/análogos & derivados , Acetilcisteína/farmacologia , Animais , Região CA1 Hipocampal/efeitos dos fármacos , Região CA1 Hipocampal/metabolismo , Região CA1 Hipocampal/fisiologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Infusões Intraventriculares , Masculino , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , Ratos , Ratos Wistar , Retenção Psicológica/fisiologia
14.
J Neural Transm (Vienna) ; 122(5): 709-19, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25182413

RESUMO

Exposure to stressful events early in life may have permanent deleterious consequences on nervous system function and increase the susceptibility to psychiatric conditions later in life. Maternal deprivation, commonly used as a source of neonatal stress, impairs memory in adult rats and reduces hippocampal brain-derived neurotrophic factor (BDNF) levels. Inflammatory cytokines, such as interleukins (IL) and tumor necrosis factor-α (TNF-α) have been shown to be increased in the peripheral blood of patients with psychiatric disorders. The aim of the present study was to investigate the effects of maternal separation on the levels of IL-10 and TNF-α, and BDNF in the hippocampus and prefrontal cortex of adult rats. We also evaluated the potential ameliorating properties of topiramate and valproic acid on memory deficits and cytokine and BDNF changes associated with maternal deprivation. The results indicated that, in addition to inducing memory deficits, maternal deprivation increased the levels of IL-10 in the hippocampus, and TNF-α in the hippocampus and in the cortex, and decreased hippocampal levels of BDNF, in adult life. Neither valproic acid nor topiramate were able to ameliorate memory deficits or the reduction in BDNF induced by maternal separation. The highest dose of topiramate was able to reduce IL-10 in the hippocampus and TNF-α in the prefrontal cortex, while valproate only reduced IL-10 levels in the hippocampus. These findings may have implications for a better understanding of the mechanisms associated with alterations observed in adult life induced by early stressful events, and for the proposal of novel therapeutic strategies.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Citocinas/metabolismo , Hipocampo/metabolismo , Privação Materna , Transtornos da Memória/metabolismo , Córtex Pré-Frontal/metabolismo , Animais , Comportamento Exploratório/efeitos dos fármacos , Comportamento Exploratório/fisiologia , Frutose/análogos & derivados , Frutose/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/crescimento & desenvolvimento , Masculino , Transtornos da Memória/tratamento farmacológico , Transtornos da Memória/etiologia , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/crescimento & desenvolvimento , Psicotrópicos/farmacologia , Ratos Wistar , Reconhecimento Psicológico/efeitos dos fármacos , Reconhecimento Psicológico/fisiologia , Estresse Psicológico/tratamento farmacológico , Estresse Psicológico/etiologia , Estresse Psicológico/metabolismo , Topiramato , Ácido Valproico/farmacologia
15.
Mol Neurobiol ; 49(1): 222-33, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23893294

RESUMO

We have recently shown that chronic treatment with cannabidiol (CBD) was able to recover memory deficits induced by brain iron loading in a dose-dependent manner in rats. Brain iron accumulation is implicated in the pathogenesis of neurodegenerative diseases, including Parkinson's and Alzheimer's, and has been related to cognitive deficits in animals and human subjects. Deficits in synaptic energy supply have been linked to neurodegenerative diseases, evidencing the key role played by mitochondria in maintaining viable neural cells and functional circuits. It has also been shown that brains of patients suffering from neurodegenerative diseases have increased expression of apoptosisrelated proteins and specific DNA fragmentation. Here, we have analyzed the expression level of brain proteins involved with mitochondrial fusion and fission mechanisms (DNM1L and OPA1), the main integral transmembrane protein of synaptic vesicles (synaptophysin), and caspase 3, an apoptosis-related protein, to gain a better understanding of the potential of CBD in restoring the damage caused by iron loading in rats. We found that CBD rescued iron-induced effects, bringing hippocampal DNM1L, caspase 3, and synaptophysin levels back to values comparable to the control group. Our results suggest that iron affects mitochondrial dynamics, possibly trigging synaptic loss and apoptotic cell death and indicate that CBD should be considered as a potential molecule with memory-rescuing and neuroprotective properties to be used in the treatment of cognitive deficits observed in neurodegenerative disorders.


Assuntos
Canabidiol/farmacologia , Caspase 3/biossíntese , Dinaminas/biossíntese , Regulação da Expressão Gênica/efeitos dos fármacos , Sobrecarga de Ferro/metabolismo , Dinâmica Mitocondrial/fisiologia , Fármacos Neuroprotetores/farmacologia , Sinaptofisina/biossíntese , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Canabidiol/uso terapêutico , Feminino , Sobrecarga de Ferro/prevenção & controle , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Dinâmica Mitocondrial/efeitos dos fármacos , Gravidez , Distribuição Aleatória , Ratos , Ratos Wistar
16.
J Alzheimers Dis ; 34(4): 797-812, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23271321

RESUMO

Over the last decades, studies from our laboratory and other groups using animal models have shown that iron overload, resulting in iron accumulation in the brain, produces significant cognitive deficits. Iron accumulation in the hippocampus and the basal ganglia has been related to impairments in spatial memory, aversive memory, and recognition memory in rodents. These results are corroborated by studies showing that the administration of iron chelators attenuates cognitive deficits in a variety of animal models of cognitive dysfunction, including aging and Alzheimer's disease models. Remarkably, recent human studies using magnetic resonance image techniques have also shown a consistent correlation between cognitive dysfunction and iron deposition, mostly in the hippocampus, cortical areas, and basal ganglia. These findings may have relevant implications in the light of the knowledge that iron accumulates in brain regions of patients suffering from neurodegenerative diseases. A better understanding of the functional consequences of iron dysregulation in aging and neurological diseases may help to identify novel targets for treating memory problems that afflict a growing aging population.


Assuntos
Encéfalo/metabolismo , Transtornos Cognitivos/patologia , Modelos Animais de Doenças , Ferro/metabolismo , Animais , Humanos
17.
Fish Physiol Biochem ; 37(3): 573-81, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21194010

RESUMO

Iron is one the most abundant metals on the earth being essential for living organisms even though its free form can be toxic. The overload of this metal may be related with some disorders, like Alzheimer and Parkinson diseases, and hemochromatosis in the liver. The aim of the present study was to evaluate the effects of iron on acetylcholinesterase (AChE) activity in brain and liver of zebrafish and to investigate the possible correlation with the iron content in these tissues. Different corresponding concentrations of iron were tested using in vitro (0.018, 0.268, and 2.6 mM) and in vivo (1, 15, and 150 mg/l) assays. The in vitro studies showed that iron promoted a significant increase in AChE activity in brain (52%) and liver (53%) at the higher concentration (2.6 mM). In the in vivo assays, a significant increase in this enzyme activity was observed in the presence of 15 mg/l in both, brain (62%) and liver tissue (70%). Semiquantitative RT-PCR did not reveal significant changes in acetylthiocholinesterase mRNA levels. Moreover, we observed that iron content was significantly increased in liver tissue when exposed to 15 (226%) and 150 mg/l (200%). These results indicate that iron can promote significant alterations in AChE activity which probably is not directly related to the iron content in zebrafish tissues.


Assuntos
Acetilcolinesterase/metabolismo , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Ferro/toxicidade , Peixe-Zebra/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Relação Dose-Resposta a Droga , Feminino , Fígado/efeitos dos fármacos , Fígado/enzimologia , Masculino
18.
Neurotox Res ; 19(4): 527-35, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-20369315

RESUMO

Oxidative stress, cellular damage, and neuronal apoptosis are believed to underlie the progressive cognitive decline that accompanies natural aging and to be exacerbated in neurodegenerative diseases. Over the years, we have consistently demonstrated that iron neonatal treatment induces oxidative stress and memory deficits in adult rats, but the mechanisms underlying these effects remained undefined. The purpose of this study was to examine whether neonatal iron overload was associated with apoptotic cell death in adult and old rats. We analyzed Par-4 and caspase-3 immunoreactivity in specific brain areas including the hippocampus CA1, CA3 and dentate gyrus (DG), the adjacent cortex and the striatum in adult (3 months-old) and aged (24 months-old) rats from control (vehicle-treated) and neonatally iron-treated groups. Neonatal iron treatment consisted of a daily oral administration of 10 mg/kg of Fe(+2), for three consecutive days, from post-natal 12-14. Control aged animals showed increased levels of both markers when compared to untreated adult animals. When adults were compared, iron-treated animals presented significantly higher Par-4 and caspase-3 immunoreactivities in CA1, CA3 and cortex. In the DG, this effect was statistically significant only for Par-4. Interestingly, when control and iron-treated aged animals were compared, a significant decrease in both apoptotic markers was observed in the later groups in the same areas. These results may be interpreted as an acceleration of aging progressive damages caused by iron overload and may contribute to a better understanding of the damaging potential of iron accumulation to brain function and the resulting increased susceptibility to neurodegeneration.


Assuntos
Envelhecimento/metabolismo , Proteínas Reguladoras de Apoptose/biossíntese , Região CA1 Hipocampal/metabolismo , Região CA3 Hipocampal/metabolismo , Córtex Cerebral/metabolismo , Ferro da Dieta/administração & dosagem , Envelhecimento/efeitos dos fármacos , Envelhecimento/patologia , Animais , Animais Recém-Nascidos , Região CA1 Hipocampal/efeitos dos fármacos , Região CA1 Hipocampal/patologia , Região CA3 Hipocampal/efeitos dos fármacos , Região CA3 Hipocampal/patologia , Caspase 3/biossíntese , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/patologia , Giro Denteado/efeitos dos fármacos , Giro Denteado/metabolismo , Giro Denteado/patologia , Feminino , Ferro da Dieta/toxicidade , Degeneração Neural/induzido quimicamente , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Gravidez , Ratos , Ratos Wistar
19.
Neurotox Res ; 20(2): 193-9, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21165730

RESUMO

This study was aimed to investigate neuropathological changes in adult and aged rats subjected to supplementary iron administration in a critical postnatal period to study the contribution of environmental risk factors to the pathogenesis of neurodegenerative disorders. Ten rats received a single daily oral administration of iron (10 mg/kg) between 12th and 14th post-natal days; nine rats received vehicle (sorbitol 5% in water) in the same period. Five iron-treated and three sorbitol-treated rats were killed at the age of 3 months while five iron-treated and six sorbitol-treated rats were killed at age of 24 months and their brains processed for immunohistochemistry. Increased astrocytosis, revealed by densitometry of GFAP-immunoreactive astrocytes, was found in aged (24 months) iron-treated rats in the substantia nigra and striatum and in the hippocampus of adult (3 months) iron-treated rats when compared to age-matching controls. Decreased densitometry of neurons, revealed by neuronal nucleus immunohistochemistry, was found in aged (24 months) iron-treated rats in substantia nigra and striatum when compared to age-matching controls. These findings suggest that transient dietary iron supplementation during the neonatal period is associated to cellular imprinting in the brain later in life.


Assuntos
Astrócitos/efeitos dos fármacos , Encéfalo/citologia , Encéfalo/crescimento & desenvolvimento , Ferro/administração & dosagem , Fatores Etários , Animais , Animais Recém-Nascidos , Astrócitos/metabolismo , Contagem de Células/métodos , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Masculino , Fosfopiruvato Hidratase/metabolismo , Gravidez , Ratos
20.
Braz J Psychiatry ; 32(1): 83-90, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20339739

RESUMO

OBJECTIVE: Translational medicine has been described as the integrated application of innovative pharmacology tools, biomarkers, clinical methods, clinical technologies and study designs to improve the understanding of medical disorders. In medicine, translational research offers an opportunity for applying the findings obtained from basic research to every-day clinical applications. The National Science and Technology Institute for Translational Medicine is comprised of six member institutions (Universidade Federal do Rio Grande do Sul, Universidade de São Paulo-Ribeirão Preto, Universidade Federal do Rio de Janeiro, Pontifícia Universidade Católica do Rio Grande do Sul, Universidade Estadual de Santa Catarina and a core facility that serves all centers). The objectives of the project are divided into four areas: Institutional, Research, Human Resources and Technology for the Community and Productive Sector. METHOD: In this manuscript, we describe some of the approaches used to attain the main objectives of the National Science and Technology Institute for Translational Medicine, which include the development of 1) animal models for bipolar disorder; 2) strategies to investigate neurobehavioral function and cognitive dysfunction associated with brain disorders; 3) experimental models of brain function and behavior, neuropsychiatric disorders, cell proliferation, and cancer; 4) Simulated Public Speaking and 5) Virtual reality simulation for inducing panic disorder and agoraphobia. CONCLUSION: The main focus of the National Science and Technology Institute for Translational Medicine is the development of more useful methods that allow for a better application of basic research-based knowledge to the medical field.


Assuntos
Academias e Institutos/organização & administração , Ciência de Laboratório Médico , Saúde Mental , Pesquisa Translacional Biomédica/organização & administração , Animais , Brasil , Protocolos Clínicos , Modelos Animais de Doenças , Órgãos dos Sistemas de Saúde/organização & administração , Humanos , Inovação Organizacional , Projetos de Pesquisa
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