RESUMO
Reactive oxygen species (ROS) are involved in neuropathic pain, a complicated condition after nerve tissue lesion. Vitamin D appears to improve symptoms of pain and exhibits antioxidant properties. We investigated the effects of oral administration of vitamin D3, the active form of vitamin D, on nociception, the sciatic functional index (SFI), and spinal cord pro-oxidant and antioxidant markers in rats with chronic constriction injury (CCI) of the sciatic nerve, a model of neuropathic pain. Vitamin D3 (500 IU/kg per day) attenuated the CCI-induced decrease in mechanical withdrawal threshold and thermal withdrawal latency (indicators of antinociception) and SFI. The vitamin prevented increased lipid hydroperoxide levels in injured sciatic nerve without change to total antioxidant capacity (TAC). Vitamin D3 prevented increased lipid hydroperoxide, superoxide anion generation (SAG), and hydrogen peroxide (H2O2) levels in the spinal cord, which were found in rats without treatment at 7 and 28 days post-CCI. A significant negative correlation was found between mechanical threshold and SAG and between mechanical threshold and H2O2 at day 7. Vitamin D3 also prevented decreased spinal cord total thiols content. There was an increase in TAC in the spinal cord of vitamin-treated CCI rats, compared to CCI rats without treatment only at 28 days. No significant changes were found in body weight and blood parameters of hepatic and renal function. These findings demonstrated, for first time, that vitamin D modulated pro-oxidant and antioxidant markers in the spinal cord. Since antinociception occurred in parallel with oxidative changes in the spinal cord, the oxidative changes may have contributed to vitamin D-induced antinociception.
Assuntos
Antioxidantes , Neuralgia , Animais , Peróxido de Hidrogênio , Hiperalgesia/tratamento farmacológico , Neuralgia/tratamento farmacológico , Nociceptividade , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio , Nervo Isquiático , Medula Espinal , Vitamina D , VitaminasRESUMO
Reactive oxygen species (ROS) are involved in neuropathic pain, a complicated condition after nerve tissue lesion. Vitamin D appears to improve symptoms of pain and exhibits antioxidant properties. We investigated the effects of oral administration of vitamin D3, the active form of vitamin D, on nociception, the sciatic functional index (SFI), and spinal cord pro-oxidant and antioxidant markers in rats with chronic constriction injury (CCI) of the sciatic nerve, a model of neuropathic pain. Vitamin D3 (500 IU/kg per day) attenuated the CCI-induced decrease in mechanical withdrawal threshold and thermal withdrawal latency (indicators of antinociception) and SFI. The vitamin prevented increased lipid hydroperoxide levels in injured sciatic nerve without change to total antioxidant capacity (TAC). Vitamin D3 prevented increased lipid hydroperoxide, superoxide anion generation (SAG), and hydrogen peroxide (H2O2) levels in the spinal cord, which were found in rats without treatment at 7 and 28 days post-CCI. A significant negative correlation was found between mechanical threshold and SAG and between mechanical threshold and H2O2 at day 7. Vitamin D3 also prevented decreased spinal cord total thiols content. There was an increase in TAC in the spinal cord of vitamin-treated CCI rats, compared to CCI rats without treatment only at 28 days. No significant changes were found in body weight and blood parameters of hepatic and renal function. These findings demonstrated, for first time, that vitamin D modulated pro-oxidant and antioxidant markers in the spinal cord. Since antinociception occurred in parallel with oxidative changes in the spinal cord, the oxidative changes may have contributed to vitamin D-induced antinociception.
Assuntos
Animais , Ratos , Neuralgia/tratamento farmacológico , Antioxidantes , Nervo Isquiático , Medula Espinal , Vitamina D , Vitaminas , Espécies Reativas de Oxigênio , Ratos Wistar , Nociceptividade , Peróxido de Hidrogênio , Hiperalgesia/tratamento farmacológicoRESUMO
Neonatal handling is an early life stressor that leads to behavioral and neurochemical changes in adult rats in a sex-specific manner and possibly affects earlier stages of development. Here, we investigated the effects of neonatal handling (days 1-10 after birth) on juvenile rats focusing on biochemical parameters and olfactory memory after weaning. Male neonatal handled rats performed more crossings on the hole-board task, increased Na+ /K+ -ATPase activity in the olfactory bulb, and decreased acetylcholinesterase activity in the hippocampus versus non-handled males. Female neonatal handled animals increased the number of rearing and nose-pokes on the hole-board task, decreased glutathione peroxidase activity, and total thiol content in the hippocampus versus non-handled females. This study reinforces that early life stress affects behavioral and neurochemical parameters in a sex-specific manner even before the puberty onset.
Assuntos
Acetilcolinesterase/metabolismo , Comportamento Animal/fisiologia , Manobra Psicológica , Hipocampo/metabolismo , Atividade Motora/fisiologia , Estresse Psicológico/metabolismo , Animais , Catalase/metabolismo , Feminino , Masculino , Ratos , Ratos Wistar , ATPase Trocadora de Sódio-Potássio/metabolismo , Superóxido Dismutase/metabolismoRESUMO
In the last decade, increased homocysteine levels have been implicated as a risk factor for neurodegenerative and psychiatric disorders. We have developed an experimental model of chronic mild hyperhomocysteinemia (HHcy) in order to observe metabolic impairments in the brain of adult rodents. Besides its known effects on brain metabolism, the present study sought to investigate whether chronic mild HHcy could induce learning/memory impairments associated with biochemical and histological damage to the hippocampus. Adult male Wistar rats received daily subcutaneous injections of homocysteine (0.03 µmol/g of body weight) twice a day, from the 30th to the 60th day of life or saline solution (Controls). After injections, anxiety-like and memory tests were performed. Following behavioral analyses, brains were sliced and hippocampal volumes assessed and homogenized for redox state assessment, antioxidant activity, mitochondrial functioning (chain respiratory enzymes and ATP levels) and DNA damage analyses. Behavioral analyses showed that chronic mild HHcy may induce anxiety-like behavior and impair long-term aversive memory (24 h) that was evaluated by inhibitory avoidance task. Mild HHcy decreased locomotor and/or exploratory activities in elevated plus maze test and caused hippocampal atrophy. Decrease in cytochrome c oxidase, DNA damage and redox state changes were also observed in hippocampus of adult rats subjected to mild HHcy. Our findings show that chronic mild HHcy alters biochemical and histological parameters in the hippocampus, leading to behavioral impairments. These findings might be considered in future studies aiming to search for alternative strategies for treating the behavioral impairments in patients with mild elevations in homocysteine levels.
Assuntos
Ansiedade/etiologia , Hipocampo/patologia , Hiper-Homocisteinemia/complicações , Transtornos da Memória/etiologia , Trifosfato de Adenosina/metabolismo , Animais , Ansiedade/patologia , Atrofia/etiologia , Atrofia/patologia , Aprendizagem da Esquiva , Doença Crônica , Dano ao DNA/fisiologia , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Hipocampo/fisiopatologia , Homocisteína/sangue , Hiper-Homocisteinemia/induzido quimicamente , Masculino , Transtornos da Memória/fisiopatologia , Teste de Campo Aberto , Estresse Oxidativo/fisiologia , Ratos , Ratos WistarRESUMO
INTRODUCTION: Perinatal hypoxia-ischemia (HI) is one of the main causes of mortality and chronic neurological morbidity in infants and children. Astrocytes play a key role in HI progression, becoming reactive in response to the injury, releasing S100 calcium binding protein B (S100B). Since S100B inhibition seems to have neuroprotective effects on central nervous system injury models, here we evaluated the neuroprotective effects of an S100B inhibitor, arundic acid (AA) in a HI model. METHODS: On the 7th postnatal day, animals were submitted to the combination of common carotid artery occlusion and hypoxic atmosphere (8% O2) for 60â¯min. Three experiments were performed in order to: (1) define AA dose (0.1, 1 or 10â¯mg/kg, pre-hypoxia i.p. injection), (2) test if repeated AA administrations (10â¯mg/kg at 3 time points: Pre-hypoxia, 24â¯h and 48â¯h after HI) would improve the response and (3) investigate biochemical mechanisms involved in AA protection two days after HI. RESULTS: AA at a dose of 10â¯mg/kg applied before and after hypoxia, was the only treatment protocol that was able to improve HI-induced memory deficits, to reduce tissue damage, to promote astrocytic survival in the hippocampus and to reduced extracellular release of S100B in the cerebrospinal fluid. CONCLUSION: Overall, AA treatment showed beneficial effects on memory deficits, tissue damage, promoting astrocyte survival likely by reducing S100B release. Protection aided to astrocytes by AA treatment against HI lesion may lead to development of new therapeutic strategies that target these particular cells.
Assuntos
Astrócitos/efeitos dos fármacos , Caprilatos/farmacologia , Hipóxia-Isquemia Encefálica/complicações , Transtornos da Memória/prevenção & controle , Fármacos Neuroprotetores/farmacologia , Animais , Animais Recém-Nascidos , Astrócitos/patologia , Encéfalo/patologia , Sobrevivência Celular/efeitos dos fármacos , Proteína Glial Fibrilar Ácida/metabolismo , Glutamato-Amônia Ligase/metabolismo , Hipóxia-Isquemia Encefálica/patologia , Aprendizagem em Labirinto/efeitos dos fármacos , Transtornos da Memória/etiologia , Ratos , Subunidade beta da Proteína Ligante de Cálcio S100/antagonistas & inibidores , Subunidade beta da Proteína Ligante de Cálcio S100/metabolismoRESUMO
Sciatic nerve transection (SNT), a model for studying neuropathic pain, mimics the clinical symptoms of "phantom limb", a pain condition that arises in humans after amputation or transverse spinal lesions. In some vertebrate tissues, this condition decreases acetylcholinesterase (AChE) activity, the enzyme responsible for fast hydrolysis of released acetylcholine in cholinergic synapses. In spinal cord of frog Rana pipiens, this enzymes activity was not significantly changed in the first days following ventral root transection, another model for studying neuropathic pain. An answerable question is whether SNT decreases AChE activity in spinal cord of frog Lithobates catesbeianus, a species that has been used as a model for studying SNT-induced neuropathic pain. Since each animal model has been created with a specific methodology, and the findings tend to vary widely with slight changes in the method used to induce pain, our study assessed AChE activity 3 and 10 days after complete SNT in lumbosacral spinal cord of adult male bullfrog Lithobates catesbeianus. Because there are time scale differences of motor endplate maturation in rat skeletal muscles, our study also measured the AChE activity in bullfrog tibial posticus (a postural muscle) and gastrocnemius (a typical skeletal muscle that is frequently used to study the motor system) muscles. AChE activity did not show significant changes 3 and 10 days following SNT in spinal cord. Also, no significant change occurred in AChE activity in tibial posticus and gastrocnemius muscles at day 3. However, a significant decrease was found at day 10, with reductions of 18% and 20% in tibial posticus and gastrocnemius, respectively. At present we cannot explain this change in AChE activity. While temporally different, the direction of the change was similar to that described for rats.[...](AU)
A transecção do nervo isquiático (SNT), um modelo para estudar dor neuropática, simula os sintomas clínicos do membro fantasma, uma condição dolorosa que ocorre nos humanos após amputação ou secção completa da medula espinal. Essa condição muda a atividade da acetilcolinesterase (AChE), a enzima responsável pela rápida hidrólise da acetilcolina liberada nas sinapses colinérgicas, em alguns tecidos de vertebrados. Em medula espinal de rã Rana pipiens, a atividade da AChE não foi significativamente alterada nos primeiros dias após a secção da raiz ventral, outro modelo para o estudo da dor neuroptípica. Uma questão ainda não respondida é se a SNT diminui a atividade da AChE na medula espinal de rã Lithobates catesbeianus, uma espécie que vem sendo usada como modelo em estudos da dor neuropática induzida por SNT. Como cada modelo animal é criado a partir de metodologia específica, e seus resultados tendem a variar com pequenas mudanças na metodologia de indução da dor, o presente estudo avaliou a atividade da AChE em medula espinal lombossacral de rã-touro Lithobates catesbeianus, adultos, machos, 3 e 10 dias após a completa SNT. Como há diferenças temporais na maturação de placas motoras em músculos esqueléticos de ratos, nosso estudo ainda demonstrou, na rã-touro, os efeitos da SNT sobre a atividade da AChE nos músculos esqueléticos tibial posticus, um músculo postural, e gastrocnêmio, um músculo frequentemente usado em estudos do sistema motor. A atividade da AChE não mudou significativamente na medula espinal aos 3 e 10 dias após a SNT. Nos músculos, a atividade não alterou significativamente aos 3 dias após a lesão, mas reduziu de forma significativa aos 10 dias após a SNT. Aos 10 dias, a diminuição foi 18% no músculo tibial posticus e 20% no gastrocnêmio. No momento, nós não temos explicação para essa mudança na atividade da AChE. Embora temporalmente diferente, o sentido da mudança é similar ao que é descrito em ratos.[...](AU)
Assuntos
Animais , Nervo Isquiático/cirurgia , Acetilcolinesterase/análise , Medula Espinal , Músculo Esquelético , Rana catesbeiana , Modelos AnimaisRESUMO
Abstract Sciatic nerve transection (SNT), a model for studying neuropathic pain, mimics the clinical symptoms of "phantom limb", a pain condition that arises in humans after amputation or transverse spinal lesions. In some vertebrate tissues, this condition decreases acetylcholinesterase (AChE) activity, the enzyme responsible for fast hydrolysis of released acetylcholine in cholinergic synapses. In spinal cord of frog Rana pipiens, this enzyme's activity was not significantly changed in the first days following ventral root transection, another model for studying neuropathic pain. An answerable question is whether SNT decreases AChE activity in spinal cord of frog Lithobates catesbeianus, a species that has been used as a model for studying SNT-induced neuropathic pain. Since each animal model has been created with a specific methodology, and the findings tend to vary widely with slight changes in the method used to induce pain, our study assessed AChE activity 3 and 10 days after complete SNT in lumbosacral spinal cord of adult male bullfrog Lithobates catesbeianus. Because there are time scale differences of motor endplate maturation in rat skeletal muscles, our study also measured the AChE activity in bullfrog tibial posticus (a postural muscle) and gastrocnemius (a typical skeletal muscle that is frequently used to study the motor system) muscles. AChE activity did not show significant changes 3 and 10 days following SNT in spinal cord. Also, no significant change occurred in AChE activity in tibial posticus and gastrocnemius muscles at day 3. However, a significant decrease was found at day 10, with reductions of 18% and 20% in tibial posticus and gastrocnemius, respectively. At present we cannot explain this change in AChE activity. While temporally different, the direction of the change was similar to that described for rats. This similarity indicates that bullfrog is a valid model for investigating AChE activity following SNT.
Resumo A transecção do nervo isquiático (SNT), um modelo para estudar dor neuropática, simula os sintomas clínicos do "membro fantasma", uma condição dolorosa que ocorre nos humanos após amputação ou secção completa da medula espinal. Essa condição muda a atividade da acetilcolinesterase (AChE), a enzima responsável pela rápida hidrólise da acetilcolina liberada nas sinapses colinérgicas, em alguns tecidos de vertebrados. Em medula espinal de rã Rana pipiens, a atividade da AChE não foi significativamente alterada nos primeiros dias após a secção da raiz ventral, outro modelo para o estudo da dor neuropática. Uma questão ainda não respondida é se a SNT diminui a atividade da AChE na medula espinal de rã Lithobates catesbeianus, uma espécie que vem sendo usada como modelo em estudos da dor neuropática induzida por SNT. Como cada modelo animal é criado a partir de metodologia específica, e seus resultados tendem a variar com pequenas mudanças na metodologia de indução da dor, o presente estudo avaliou a atividade da AChE em medula espinal lombossacral de rã-touro Lithobates catesbeianus, adultos, machos, 3 e 10 dias após a completa SNT. Como há diferenças temporais na maturação de placas motoras em músculos esqueléticos de ratos, nosso estudo ainda demonstrou, na rã-touro, os efeitos da SNT sobre a atividade da AChE nos músculos esqueléticos tibial posticus, um músculo postural, e gastrocnêmio, um músculo frequentemente usado em estudos do sistema motor. A atividade da AChE não mudou significativamente na medula espinal aos 3 e 10 dias após a SNT. Nos músculos, a atividade não alterou significativamente aos 3 dias após a lesão, mas reduziu de forma significativa aos 10 dias após a SNT. Aos 10 dias, a diminuição foi 18% no músculo tibial posticus e 20% no gastrocnêmio. No momento, nós não temos explicação para essa mudança na atividade da AChE. Embora temporalmente diferente, o sentido da mudança é similar ao que é descrito em ratos. Esta similaridade torna a rã-touro um modelo válido para se estudar questões ainda não respondidas da SNT sobre a AChE.
Assuntos
Animais , Acetilcolinesterase/metabolismo , Nervo Isquiático/enzimologia , Nervo Isquiático/fisiopatologia , Nervo Isquiático/lesões , Medula Espinal/fisiologia , Músculo Esquelético/inervação , Rana catesbeianaRESUMO
Sciatic nerve transection (SNT), a model for studying neuropathic pain, mimics the clinical symptoms of "phantom limb", a pain condition that arises in humans after amputation or transverse spinal lesions. In some vertebrate tissues, this condition decreases acetylcholinesterase (AChE) activity, the enzyme responsible for fast hydrolysis of released acetylcholine in cholinergic synapses. In spinal cord of frog Rana pipiens, this enzyme's activity was not significantly changed in the first days following ventral root transection, another model for studying neuropathic pain. An answerable question is whether SNT decreases AChE activity in spinal cord of frog Lithobates catesbeianus, a species that has been used as a model for studying SNT-induced neuropathic pain. Since each animal model has been created with a specific methodology, and the findings tend to vary widely with slight changes in the method used to induce pain, our study assessed AChE activity 3 and 10 days after complete SNT in lumbosacral spinal cord of adult male bullfrog Lithobates catesbeianus. Because there are time scale differences of motor endplate maturation in rat skeletal muscles, our study also measured the AChE activity in bullfrog tibial posticus (a postural muscle) and gastrocnemius (a typical skeletal muscle that is frequently used to study the motor system) muscles. AChE activity did not show significant changes 3 and 10 days following SNT in spinal cord. Also, no significant change occurred in AChE activity in tibial posticus and gastrocnemius muscles at day 3. However, a significant decrease was found at day 10, with reductions of 18% and 20% in tibial posticus and gastrocnemius, respectively. At present we cannot explain this change in AChE activity. While temporally different, the direction of the change was similar to that described for rats. This similarity indicates that bullfrog is a valid model for investigating AChE activity following SNT.
Assuntos
Acetilcolinesterase/metabolismo , Músculo Esquelético/inervação , Nervo Isquiático , Medula Espinal/fisiologia , Animais , Rana catesbeiana , Nervo Isquiático/enzimologia , Nervo Isquiático/lesões , Nervo Isquiático/fisiopatologiaRESUMO
In animal models, environmental enrichment (EE) has been found to be an efficient treatment for alleviating the consequences of neonatal hypoxia-ischemia (HI). However the potential for this therapeutic strategy and the mechanisms involved are not yet clear. The aim of present study is to investigate behavioral performance in the ox-maze test and Na+,K+-ATPase, catalase (CAT) and glutathione peroxidase (GPx) activities in the hippocampus of rats that suffered neonatal HI and were stimulated in an enriched environment. Seven-day-old rats were submitted to the HI procedure and divided into four groups: control maintained in standard environment (CTSE), control submitted to EE (CTEE), HI in standard environment (HISE) and HI in EE (HIEE). Animals were stimulated with EE for 9 weeks (1 h/day for 6 days/week) and then behavioral and biochemical parameters were evaluated. Present results indicate learning and memory in the ox-maze task were impaired in HI rats and this effect was recovered after EE. Hypoxic-ischemic event did not alter the Na+,K+-ATPase activity in the right hippocampus (ipsilateral to arterial occlusion). However, on the contralateral hemisphere, HI caused a decrease in this enzyme activity that was recovered by EE. The activities of GPx and CAT were not changed by HI in any group evaluated. In conclusion, EE was effective in recovering learning and memory impairment in the ox-maze task and Na+,K+-ATPase activity in the hippocampus caused by HI. The present data provide further support for the therapeutic potential of environmental stimulation after neonatal HI in rats.
Assuntos
Meio Ambiente , Hipocampo/enzimologia , Hipóxia-Isquemia Encefálica/terapia , Aprendizagem em Labirinto/fisiologia , Transtornos da Memória/terapia , ATPase Trocadora de Sódio-Potássio/metabolismo , Animais , Animais Recém-Nascidos , Catalase/metabolismo , Modelos Animais de Doenças , Glutationa Peroxidase/metabolismo , Hipóxia-Isquemia Encefálica/complicações , Hipóxia-Isquemia Encefálica/enzimologia , Deficiências da Aprendizagem/enzimologia , Deficiências da Aprendizagem/etiologia , Deficiências da Aprendizagem/terapia , Transtornos da Memória/enzimologia , Transtornos da Memória/etiologia , Distribuição Aleatória , Ratos Wistar , Resultado do TratamentoRESUMO
Hyperprolinemia is an inherited disorder of proline metabolism and hyperprolinemic patients can present neurological manifestations, such as seizures, cognitive dysfunctions, and schizoaffective disorders. However, the mechanisms related to these symptoms are still unclear. In the present study, we evaluated the in vivo and in vitro effects of proline on acetylcholinesterase (AChE) activity and gene expression in the zebrafish brain. For the in vivo studies, animals were exposed at two proline concentrations (1.5 and 3.0mM) during 1h or 7 days (short- or long-term treatments, respectively). For the in vitro assays, different proline concentrations (ranging from 3.0 to 1000 µM) were tested. Long-term proline exposures significantly increased AChE activity for both treated groups when compared to the control (34% and 39%). Moreover, the proline-induced increase on AChE activity was completely reverted by acute administration of antipsychotic drugs (haloperidol and sulpiride), as well as the changes induced in ache expression. When assessed in vitro, proline did not promote significant changes in AChE activity. Altogether, these data indicate that the enzyme responsible for the control of acetylcholine levels might be altered after proline exposure in the adult zebrafish. These findings contribute for better understanding of the pathophysiology of hyperprolinemia and might reinforce the use of the zebrafish as a complementary vertebrate model for studying inborn errors of amino acid metabolism.
Assuntos
Acetilcolinesterase/metabolismo , Antipsicóticos/farmacologia , Química Encefálica/efeitos dos fármacos , Química Encefálica/genética , Encéfalo/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Prolina/farmacologia , Peixe-Zebra/fisiologia , Animais , Feminino , Haloperidol/farmacologia , Técnicas In Vitro , Masculino , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/genética , Sistema Nervoso Parassimpático/efeitos dos fármacos , Prolina/antagonistas & inibidores , Reação em Cadeia da Polimerase em Tempo Real , Sulpirida/farmacologiaRESUMO
Physical exercise during pregnancy has been considered beneficial to mother and child. Recent studies showed that maternal swimming improves memory in the offspring, increases hippocampal neurogenesis and levels of neurotrophic factors. The objective of this work was to investigate the effect of maternal swimming during pregnancy on redox status and mitochondrial parameters in brain structures from the offspring. Adult female Wistar rats were submitted to five swimming sessions (30 min/day) prior to mating with adult male Wistar rats, and then trained during the pregnancy (five sessions of 30-min swimming/week). The litter was sacrificed when 7 days old, when cerebellum, parietal cortex, hippocampus, and striatum were dissected. We evaluated the production of reactive species and antioxidant status, measuring the activities of superoxide-dismutase (SOD), catalase (CAT) and glutathione-peroxidase (GPx), as well as non-enzymatic antioxidants. We also investigated a potential mitochondrial biogenesis regarding mitochondrion mass and membrane potential, through cytometric approaches. Our results showed that maternal swimming exercise promoted an increase in reactive species levels in cerebellum, parietal cortex, and hippocampus, demonstrated by an increase in dichlorofluorescein oxidation. Mitochondrial superoxide was reduced in cerebellum and parietal cortex, while nitrite levels were increased in cerebellum, parietal cortex, hippocampus, and striatum. Antioxidant status was improved in cerebellum, parietal cortex, and hippocampus. SOD activity was increased in parietal cortex, and was not altered in the remaining brain structures. CAT and GPx activities, as well as non-enzymatic antioxidant potential, were increased in cerebellum, parietal cortex, and hippocampus of rats whose mothers were exercised. Finally, we observed an increased mitochondrial mass and membrane potential, suggesting mitochondriogenesis, in cerebellum and parietal cortex of pups subjected to maternal swimming. In conclusion, maternal swimming exercise induced neurometabolic programing in the offspring that could be of benefit to the rats against future cerebral insults.
Assuntos
Antioxidantes/metabolismo , Encéfalo/metabolismo , Mitocôndrias/metabolismo , Condicionamento Físico Animal/fisiologia , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Natação/fisiologia , Animais , Animais Recém-Nascidos , Feminino , Masculino , Potencial da Membrana Mitocondrial/fisiologia , Biogênese de Organelas , Gravidez , Ratos , Ratos WistarRESUMO
Hypoxia-ischemia on 3-day-old rats (HIP3) allows the investigation of HI damage in the immature brain. HIP3 is characterized for neurological disabilities caused by white matter injury. This study investigates the relationship between animals' sex and injured hemisphere on HIP3 consequences. Male and female Wistar rats had their right or left common carotid artery occluded under halotane anesthesia and exposed to 8% O2 for 1.5 h. Control rats received sham surgery and exposure to 1.5 h of room air in isolation of their mothers. Sex and injured hemisphere influence in Na+/K+ -ATPase activity 24h after lesion: females and the right brain hemispheres showed decreased enzymatic activity after HIP3. Cognitive impairment was observed in step-down inhibitory avoidance, in which females HIP3 left injured were the most damaged. Histological analysis showed a trend to white matter damage in females left injured without hemispherical nor hippocampal volume decrease in HIP3 rats at postnatal day 21. However, at PND90, hemisphere and sex effects were noted in hemispherical volume and myelination: left brain hemisphere and the females evidenced higher histological damage. Our results points to an increased resistance of male rats and right brain hemisphere to support the impairment caused in Na+/K+ -ATPase activity early after HIP3, and evidencing more discrete behavioral impairments and histological damage at adulthood. Present data adds new evidence of distinct effects of brain lateralization and sex vulnerability on biochemical, behavioral and histological parameters after hypoxia-ischemia.
Assuntos
Encéfalo/patologia , Hipóxia-Isquemia Encefálica/patologia , Hipóxia-Isquemia Encefálica/psicologia , Animais , Animais Recém-Nascidos , Aprendizagem da Esquiva/fisiologia , Encéfalo/enzimologia , Lesões das Artérias Carótidas/enzimologia , Lesões das Artérias Carótidas/patologia , Lesões das Artérias Carótidas/psicologia , Feminino , Lateralidade Funcional/fisiologia , Hipóxia-Isquemia Encefálica/enzimologia , Masculino , Atividade Motora/fisiologia , Fibras Nervosas Mielinizadas/patologia , Ratos , Ratos Wistar , Fatores Sexuais , ATPase Trocadora de Sódio-Potássio/análiseRESUMO
Since homocysteine (Hcy) is considered a risk factor to cerebral diseases and adenine nucleotides are important molecules to brain normal function, in the present study we investigated the effect of chronic mild hyperhomocysteinemia on ectonucleotidase activities and expression in rat cerebral cortex. The levels of ATP, ADP, AMP and adenosine (Ado) in cerebrospinal fluid (CSF) of adult rats also were evaluated by high-performance liquid chromatography. For the chronic chemically induced mild hyperhomocysteinemia, Hcy (0.03 µmol/g of body weight) was administered subcutaneously from the 30th to the 60th day of life. Control rats received saline solution in the same volumes. Results showed that Hcy significantly decreased nucleotide hydrolysis in the synaptosomal fraction and increased E-NTPDase1 and ecto-5'-nucleotidase transcripts in rat cerebral cortex. ATP levels were significantly increased, while Ado decreased in CSF of Hcy-treated rats. These findings suggest that the unbalance in ATP and Ado levels may be, at last in part, involved in the cerebral toxicity of mild hyperhomocysteinemia.
Assuntos
Adenina/metabolismo , Encéfalo/patologia , Líquido Extracelular/metabolismo , Hiper-Homocisteinemia/patologia , 5'-Nucleotidase/genética , 5'-Nucleotidase/metabolismo , Difosfato de Adenosina/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/ultraestrutura , Modelos Animais de Doenças , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/metabolismo , Regulação Enzimológica da Expressão Gênica , Hiper-Homocisteinemia/metabolismo , Purinas/líquido cefalorraquidiano , RNA Mensageiro , Ratos , Ratos Wistar , Frações Subcelulares/metabolismo , Frações Subcelulares/patologia , Sinaptossomos/metabolismoRESUMO
Social isolation during postnatal development leads to behavioral and neurochemical changes, and a particular susceptibility of the prefrontal cortex to interventions during this period has been suggested. In addition, some studies showed that consumption of a palatable diet reduces some of the stress effects. Therefore, our aim is to investigate the effect of isolation stress in early life on some parameters of oxidative stress and energy metabolism (Na(+),K(+)-ATPase activity, respiratory chain enzymes activities and mitochondrial mass and potential) in prefrontal cortex of juvenile and adult male rats. We also verified if the consumption of a palatable diet during the prepubertal period would reduce stress effects. The results showed that, in juvenile animals, isolation stress increased superoxide dismutase and Complex IV activities and these effects were still observed in the adulthood. An interaction between stress and diet was observed in catalase activity in juveniles, while only the stress effect was detected in adults, reducing catalase activity. Access to a palatable diet increased Na(+),K(+)-ATPase activity in juveniles, an effect that was reversed after removing this diet. On the other hand, isolation stress induced a decreased activity of this enzyme in adulthood. No effects were observed on glutathione peroxidase, total thiols and free radicals production, as well as on mitochondrial mass and potential. In conclusion, isolation stress in the prepubertal period leads to long-lasting changes on antioxidant enzymes and energetic metabolism in the prefrontal cortex of male rats, and a palatable diet was not able to reverse these stress-induced effects.
Assuntos
Córtex Pré-Frontal/metabolismo , Isolamento Social , Estresse Psicológico , Animais , Catalase/metabolismo , Transporte de Elétrons , Glutationa Peroxidase/metabolismo , Masculino , Potenciais da Membrana , Mitocôndrias/metabolismo , Córtex Pré-Frontal/enzimologia , Ratos , Ratos Wistar , ATPase Trocadora de Sódio-Potássio/metabolismoRESUMO
In the present study, we first investigated the effect of single homocysteine administration on consolidation of short- and long-term memories of inhibitory avoidance task in Wistar rats. We also measured brain-derived neurotrophic factor levels in the hippocampus and parietal cortex of rats. The influence of pretreatment with folic acid on behavioral and biochemical effects elicited by homocysteine was also studied. Wistar rats were subjected to a folic acid or saline pretreatment from their 22(nd) to 28(th) day of life; 12 h later they were submitted to a single administration of homocysteine or saline. For motor activity and memory evaluation we performed open-field and inhibitory avoidance tasks. Hippocampus and parietal cortex were obtained for brain-derived neurotrophic factor immunocontent determination. Results showed that homocysteine impaired short- and long-term memories and reduced brain-derived neurotrophic factor levels in the hippocampus. Pretreatment with folic acid prevented both the memory deficit and the reduction in the brain-derived neurotrophic factor immunocontent induced by homocysteine injection. Further studies are required to determine the entire mechanism by which folic acid acts and its potential therapeutic use for memory impairment prevention in homocystinuric patients.
Assuntos
Aprendizagem da Esquiva/fisiologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Ácido Fólico/metabolismo , Hipocampo/fisiologia , Homocisteína/metabolismo , Memória/fisiologia , Animais , Ácido Fólico/uso terapêutico , Hiper-Homocisteinemia/complicações , Hiper-Homocisteinemia/metabolismo , Transtornos da Memória/complicações , Transtornos da Memória/metabolismo , Transtornos da Memória/terapia , Memória de Curto Prazo/fisiologia , Atividade Motora/fisiologia , Lobo Parietal/fisiologia , Distribuição Aleatória , Ratos , Ratos Wistar , Fatores de Tempo , Complexo Vitamínico B/metabolismo , Complexo Vitamínico B/uso terapêuticoRESUMO
We have previously demonstrated that octanoic (OA) and decanoic acids (DA) inhibit Na+, K+ ATPase activity in synaptic plasma membranes from rat brain. The objective of the present study was to investigate the in vitro effects of the other metabolites that accumulate in tissues of medium-chain acyl-CoA dehydrogenase (MCAD)-deficient patients, namely cis-4-decenoic acid (cDA), octanoylcarnitine (OC), hexanoylcarnitine (HC), hexanoylglycine (HG), phenylpropionylglycine (PPG) and suberoylglycine (SG), on Na+, K+ ATPase activity in synaptic plasma membrane from cerebral cortex of 30-day-old rats. cDA, the pathognomonic compound found in this disorder, provoked the strongest inhibition on this enzyme activity at concentrations as low as 0.25 mM, whereas OC inhibited this activity at 1.0 mM and higher concentrations in a dose-dependent manner. In contrast, HC, HG, PPG and SG did not affect Na+, K+ ATPase activity. Furthermore, pre-treatment of cortical homogenates with the antioxidant enzymes catalase plus superoxide dismutase totally prevented cDA-induced Na+, K+ ATPase inhibition. We also provided evidence that cDA, as well as OA and DA, caused lipid peroxidation, which may explain, at least in part, the inhibitory properties of these compounds towards Na+, K+ ATPase. Considering that Na+, K+ ATPase is a critical enzyme for normal brain development and functioning, it is presumed that these findings, especially those regarding to the marked inhibitory effect of cDA, may be involved in the pathophysiology of the neurological dysfunction of MCAD-deficient patients.
Assuntos
Córtex Cerebral/enzimologia , Inibidores Enzimáticos , Ácidos Graxos Monoinsaturados/farmacologia , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Membranas Sinápticas/enzimologia , Acil-CoA Desidrogenase/deficiência , Animais , Antioxidantes/farmacologia , Carnitina/análogos & derivados , Carnitina/farmacologia , Córtex Cerebral/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Medições Luminescentes , Ratos , Ratos Wistar , Membranas Sinápticas/efeitos dos fármacos , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
The main objective of the present study was to evaluate the in vivo and in vitro effect of Arg on serum nucleotide hydrolysis. The action of Nomega-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase, on the effects produced by Arg was also examined. Sixty-day-old rats were treated with a single or a triple (with an interval of 1 h between each injection) intraperitoneal injection of saline (group I), Arg (0.8 g/kg) (group II), L-NAME (2.0 mg/kg or 20 mg/kg) (group III) or Arg (0.8 g/kg) plus L-NAME (2.0 mg/kg or 20 mg/kg) (group IV) and were killed 1 h later. The present results show that a triple Arg administration decreased ATP, ADP and AMP hydrolysis. Simultaneous injection of L-NAME (20 mg/kg) prevented such effects. Arg in vitro did not alter nucleotide hydrolysis. It is suggested that in vivo Arg administration reduces nucleotide hydrolysis in rat serum, probably through nitric oxide or/and peroxynitrite formation.
Assuntos
Arginina/antagonistas & inibidores , Hiperargininemia/sangue , NG-Nitroarginina Metil Éster/administração & dosagem , Nucleotídeos/metabolismo , Difosfato de Adenosina/sangue , Difosfato de Adenosina/metabolismo , Monofosfato de Adenosina/sangue , Monofosfato de Adenosina/metabolismo , Trifosfato de Adenosina/sangue , Trifosfato de Adenosina/metabolismo , Animais , Arginina/administração & dosagem , Hidrólise/efeitos dos fármacos , Técnicas In Vitro , Masculino , Nucleotídeos/sangue , Ratos , Ratos WistarRESUMO
Mitochondrial beta-ketothiolase and 2-methyl-3-hydroxybutyryl-CoA dehydrogenase (MHBD) deficiencies are inherited neurometabolic disorders affecting isoleucine catabolism. Biochemically, beta-ketothiolase deficiency is characterized by intermittent ketoacidosis and urinary excretion of 2-methyl-acetoacetate (MAA), 2-methyl-3-hydroxybutyrate (MHB) and tiglylglycine (TG), whereas in MHBD deficiency only MHB and tiglylglycine accumulate. Lactic acid accumulation and excretion are also observed in these patients, being more pronounced in MHBD-deficient individuals, particularly during acute episodes of decompensation. Patients affected by MHBD deficiency usually manifest severe mental retardation and convulsions, whereas beta-ketothiolase-deficient patients present encephalopathic crises characterized by metabolic acidosis, vomiting and coma. Considering that the pathophysiological mechanisms responsible for the neurological alterations of these disorders are unknown and that lactic acidosis suggests an impairment of energy production, the objective of the present work was to investigate the in vitro effect of MAA and MHB, at concentrations varying from 0.01 to 1.0 mmol/L, on several parameters of energy metabolism in cerebral cortex from young rats. We observed that MAA markedly inhibited CO2 production from glucose, acetate and citrate at concentrations as low as 0.01 mmol/L. In addition, the activities of the respiratory chain complex II and succinate dehydrogenase were mildly inhibited by MAA. MHB, at 0.01 mmol/L and higher concentrations, strongly inhibited CO2 production from all tested substrates, as well as the respiratory chain complex IV activity. The other activities of the respiratory chain were not affected by these metabolites. The data indicate a marked blockage in the Krebs cycle and a mild inhibition of the respiratory chain caused by MAA and MHB. Furthermore, MHB inhibited total and mitochondrial creatine kinase activities, which was prevented by the use of the nitric-oxide synthase inhibitor L-NAME and glutathione (GSH). These data indicate that the effect of MHB on creatine kinase was probably mediated by oxidation or other modification of essential thiol groups of the enzyme by nitric oxide and other by-products derived from this organic acid. In contrast, MAA did not affect creatine kinase activity. Taken together, these observations indicate that aerobic energy metabolism is inhibited by MAA and to a greater extent by MHB, a fact that may be related to lactic acidaemia occurring in patients affected by MHBD and beta-ketothiolase deficiencies. If the in vitro effects detected in the present study also occur in vivo, it is tempting to speculate that they may contribute, at least in part, to the neurological dysfunction found in these disorders.
Assuntos
Acetoacetatos/farmacologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/embriologia , Metabolismo Energético , Hidroxibutiratos/farmacologia , 3-Hidroxiacil-CoA Desidrogenases , Acetatos/metabolismo , Acetil-CoA C-Aciltransferase/metabolismo , Acidose/metabolismo , Oxirredutases do Álcool/metabolismo , Animais , Encéfalo/metabolismo , Dióxido de Carbono/química , Dióxido de Carbono/metabolismo , Córtex Cerebral/metabolismo , Citratos/metabolismo , Creatina Quinase/metabolismo , Relação Dose-Resposta a Droga , Transporte de Elétrons , Glucose/metabolismo , Glutationa/metabolismo , Glicina/análogos & derivados , Glicina/metabolismo , Técnicas In Vitro , Deficiência Intelectual , Ácido Láctico/metabolismo , NG-Nitroarginina Metil Éster/metabolismo , NG-Nitroarginina Metil Éster/farmacologia , Oxigênio/metabolismo , Ratos , Ratos Wistar , Fatores de TempoRESUMO
We observed here that acute proline (Pro) administration provoked a decrease (32%) of acetylcholinesterase (AChE) activity in cerebral cortex and an increase (22%) of butyrylcholinesterase (BuChE) activity in the serum of 29-day-old rats. In contrast, chronic administration of Pro did not alter AChE or BuChE activities. Furthermore, pretreatment of rats with vitamins E and C combined or alone, N(omega)-nitro-L-arginine methyl ester or melatonin prevented the reduction of AChE activity caused by acute Pro administration, suggesting the participation of oxidative stress in such effects.
Assuntos
Acetilcolinesterase/efeitos adversos , Química Encefálica/efeitos dos fármacos , Butirilcolinesterase/sangue , Córtex Cerebelar/enzimologia , Doenças Metabólicas/sangue , Prolina/efeitos adversos , Animais , Doenças Metabólicas/induzido quimicamente , Estresse Oxidativo/efeitos dos fármacos , Prolina/administração & dosagem , Ratos , Ratos WistarRESUMO
Organic acidurias represent a group of inherited disorders resulting from deficient activity of specific enzymes of the catabolism of amino acids, carbohydrates or lipids, leading to tissue accumulation of one or more carboxylic (organic) acids. Patients affected by organic acidurias predominantly present neurological symptoms and structural brain abnormalities, of which the aetiopathogenesis is poorly understood. However, in recent years increasing evidence has emerged suggesting that oxidative stress is possibly involved in the pathology of some organic acidurias and other inborn errors of metabolism. This review addresses some of the recent developments obtained mainly from animal studies indicating oxidative damage as an important determinant of the neuropathophysiology of some organic acidurias. Recent data showing that various organic acids are capable of inducing free radical generation and decreasing brain antioxidant defences is presented. The discussion focuses on the relatively low antioxidant defences of the brain and the vulnerability of this tissue to reactive species. This offers new perspectives for potential therapeutic strategies for these disorders, which may include the early use of appropriate antioxidants as a novel adjuvant therapy, besides the usual treatment based on removing toxic compounds and using special diets and pharmacological agents, such as cofactors and L-carnitine.