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Nyaope is a local adulterated drug that contributes significantly to the psychosocial challenge of substance use in South Africa. Despite being a huge burden on society and the health care system, research into the deleterious effects of nyaope is limited. The aim of the present study was therefore to perform a chemical analysis of the drug and to assess its toxic effects on neuroblastoma cells. Gas chromatography-mass spectrometry (GC/MS) analysis showed that nyaope mainly consists of heroin and heroin-related products. SH-SY5Y cells were subsequently exposed to increasing concentrations of nyaope (0.625, 1.25, 2.5, 5 and 10 µg/µL) for 1, 6 or 24 h. The toxic effects of nyaope were determined by measuring lactate dehydrogenase (LDH) released into the cell culture medium as an indicator of necrosis, the mRNA expression levels of Bax and Bcl-2 as markers of apoptosis, and the mRNA expression levels of p62 and microtubule-associated protein 1 A/1B light-chain 3 (LC3) as indicators of autophagy. Exposing SH-SY5Y cells to concentrations of nyaope 5 µg/µL and greater for 24 h, resulted in a significant increase in LDH levels in the cell culture medium, unchanged mRNA expression of Bax and Bcl-2 mRNA, and significantly reduced p62 and elevated LC3 mRNA expression levels. The chemical analysis suggests that nyaope should be considered synonymous with heroin and the toxic effects of the drug may recruit pathways involved in necrosis and autophagy.
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Biological psychiatry scholarship on posttraumatic stress disorder (PTSD) is making strides with new omics technologies. In this context, there is growing recognition that noncoding RNAs are vital for the regulation of gene and protein expression. Long noncoding RNAs (lncRNAs) can modulate splicing, influence RNA editing, messenger RNA (mRNA) stability, translation activation, and microRNA-mRNA interactions, are highly abundant in the brain, and have been implicated in neurodevelopmental disorders. The largest subclass of lncRNAs is long intergenic noncoding RNAs (lincRNAs). We report on lincRNAs and their predicted mRNA targets associated with fear extinction induced by co-administration of D-cycloserine and behavioral fear extinction in a PTSD animal model. Forty-three differentially expressed lincRNAs and 190 differentially expressed mRNAs were found to be associated with fear extinction. Eight lincRNAs were predicted to interact with and regulate 108 of these mRNAs, while seven lincRNAs were predicted to interact with 22 of their pre-mRNA transcripts. Based on the functions of their target mRNAs, we inferred that these lincRNAs bind to nucleotides, ribonucleotides, and proteins; subsequently influence nervous system development, morphology, and immune system functioning; and could be associated with nervous system and mental health disorders. We found the quantitative trait loci that overlapped with fear extinction-related lincRNAs included traits such as serum corticosterone level, neuroinflammation, anxiety, stress, and despair-related responses. To the best of our knowledge, this is the first study to identify lincRNAs and their RNA targets with a putative role in transcriptional regulation during fear extinction in the context of an animal model of PTSD.
Assuntos
Emoções , Perfilação da Expressão Gênica , Transtornos Mentais/etiologia , Transtornos Mentais/psicologia , Transcriptoma , Animais , Biologia Computacional/métodos , Ciclosserina/efeitos adversos , Modelos Animais de Doenças , Suscetibilidade a Doenças , Extinção Psicológica , Medo , Regulação da Expressão Gênica , Ontologia Genética , Masculino , Locos de Características Quantitativas , RNA Longo não Codificante/genética , RNA Mensageiro/genética , Ratos , Transtornos de Estresse Pós-Traumáticos/etiologia , Transtornos de Estresse Pós-Traumáticos/psicologiaRESUMO
Studies have shown that inflammation and neurodegeneration may accompany the development of addiction to apomorphine and that the glutamate NMDA receptor antagonist, memantine, may be neuroprotective. The similarity between apomorphine and dopamine with regard to their chemical, pharmacological and toxicological properties provided a basis for investigating the mechanism of action of the former agent. In this study, we investigated whether memantine would suppress apomorphine-seeking behavior in rats subjected to apomorphine-induced place preference conditioning, through modulation of NMDA receptors in the prefrontal cortex. Repeated apomorphine (1 mg/kg) treatment induced conditioned place preference (CPP) and had no significant effect on NMDA receptor levels in the prefrontal cortex. Prior treatment with memantine (5 mg/kg or 10 mg/kg) increased the levels of NMDA receptors in the prefrontal cortex but did not suppress CPP induced by apomorphine. These data give further support to the addictive effect of apomorphine and demonstrate that blockade of NMDA receptors by memantine is unable to suppress apomorphine-seeking behavior.
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OBJECTIVES: Post-traumatic stress disorder is characterized by impaired fear extinction and excessive anxiety. D-Cycloserine (DCS) has previously been shown to facilitate fear extinction and decrease anxiety in animal and human studies. This study utilized a contextual fear-conditioning animal model to investigate the involvement of microRNAs (miRNAs) in fear extinction and the reduction of anxiety, as mediated by the co-administration of DCS and behavioural fear extinction. METHODS: Fear conditioning consisted of an electric foot shock; fear extinction consisted of behavioural fear extinction co-administered with either DCS or saline. The light/dark avoidance test was used to evaluate anxiety-related behaviour subsequent to fear conditioning and was used to evaluate anxiety-related behaviour following fear conditioning and to subsequently group animals into well-adapted and maladapted subgroups. These subgroups also showed significant differences in terms of fear extinction. Small RNAs extracted from the left dorsal hippocampus were sequenced using next-generation sequencing to identify differentially expressed miRNAs associated with DCS-induced fear extinction and reduction of anxiety. In-silico prediction analyses identified mRNA targets (from data of the same animals) of the differentially expressed miRNAs. Two of the predicted mRNA-miRNA interactions were functionally investigated. RESULTS: Overall, 32 miRNAs were differentially expressed between rats that were fear conditioned, received DCS and were well adapted and rats that were fear conditioned, received saline and were maladapted. Nineteen of these miRNAs were predicted to target and regulate the expression of 63 genes differentially expressed between fear-conditioned, DCS-administered, well-adapted and fear-conditioned, saline-administered, and maladapted groups (several of which are associated with neuronal inflammation, learning and memory). Functional luciferase assays indicated that rno-mir-31a-5p may have regulated the expression of interleukin 1 receptor antagonist (Il1rn) and metallothionein 1a (Mt1a). CONCLUSION: These differentially expressed miRNAs may be mediators of gene expression changes that facilitated decreased neuronal inflammation, optimum learning and memory and contributed towards effective fear extinction and reduction of anxiety following the co-administration of DCS and behavioural fear extinction.
Assuntos
MicroRNAs/uso terapêutico , Transtornos de Estresse Pós-Traumáticos/tratamento farmacológico , Transtornos de Estresse Pós-Traumáticos/genética , Animais , Ansiedade/genética , Ansiedade/fisiopatologia , Transtornos de Ansiedade , Condicionamento Clássico/fisiologia , Ciclosserina/farmacologia , Ciclosserina/uso terapêutico , Modelos Animais de Doenças , Extinção Psicológica/fisiologia , Medo/efeitos dos fármacos , Medo/fisiologia , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Hipocampo/fisiopatologia , Masculino , Memória , MicroRNAs/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/metabolismoRESUMO
Parkinson's disease (PD) is also associated with cognitive impairment and reduced extrinsic supply of dopamine (DA) to the prefrontal cortex (PFC). In the present study, we looked at whether exposure to early life stress reduces DA and serotonin (5-HT) concentration in the PFC thus leading to enhanced cognitive impairment in a Parkinsonian rat model. Maternal separation was the stressor used to develop an animal model for early life stress that has chronic effects on brain and behavior. Sprague-Dawley rats were treated with the antidepressant Fluvoxamine maleate (FM) prior to a unilateral 6-hydroxydopamine (6-OHDA) lesion to model motor deficits in rats. The Morris water maze (MWM) and the forelimb use asymmetry (cylinder) tests were used to assess learning and memory impairment and motor deficits respectively. Blood plasma was used to measure corticosterone concentration and prefrontal tissue was collected for lipid peroxidation, DA, and 5-HT analysis. Our results show that animals exposed to early life stress displayed learning and memory impairment as well as elevated basal plasma corticosterone concentration which were attenuated by treatment with FM. A 6-OHDA lesion effect was evidenced by impairment in the cylinder test as well as decreased DA and 5-HT concentration in the PFC. These effects were attenuated by FM treatment resulting in higher DA concentration in the PFC of treated animals than in non-treated animals. This study suggests that DA and 5-HT signaling in the PFC are responsive to FM and may reduce stress-induced cognitive impairment in PD.
Assuntos
Dopamina/metabolismo , Fluvoxamina/farmacologia , Neurotransmissores/farmacologia , Transtornos Parkinsonianos/tratamento farmacológico , Córtex Pré-Frontal/efeitos dos fármacos , Estresse Psicológico/metabolismo , Animais , Corticosterona/sangue , Aprendizagem/efeitos dos fármacos , Aprendizagem/fisiologia , Deficiências da Aprendizagem/tratamento farmacológico , Deficiências da Aprendizagem/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Peroxidação de Lipídeos/fisiologia , Masculino , Privação Materna , Memória/efeitos dos fármacos , Memória/fisiologia , Transtornos da Memória/tratamento farmacológico , Transtornos da Memória/metabolismo , Nootrópicos/farmacologia , Oxidopamina , Transtornos Parkinsonianos/metabolismo , Transtornos Parkinsonianos/psicologia , Córtex Pré-Frontal/metabolismo , Distribuição Aleatória , Ratos Sprague-Dawley , Serotonina/metabolismoRESUMO
Cytokine dysfunction is associated with both depression and Parkinson's disease (PD) pathophysiology. Inflammatory cytokines in neural and behavioral processes are involved in the production and/or maintenance of depression in PD. In this study we looked at how Fluvoxamine treatment regulates depressive-like signs, motor impairments and the expression of IL-1ß, IL-6, TNF-α, TGF-ß and IL-10 cytokines in the striatum of a stressed Parkinsonian rat model. Early maternal separation was used to model stress and depressive-like signs in rats. Maternally separated adult rats were treated with Fluvoxamine for 30days prior to 6-hydroxydopamine (6-OHDA) lesion. The sucrose preference test (SPT) and the limb-use asymmetry test (cylinder test) were used to evaluate anhedonia and motor impairments respectively. Lipid peroxidation and cytokine expression were measured in striatal tissue using ELISA and real-time PCR techniques respectively. Our results show that maternal separation resulted in anhedonia and exacerbated 6-OHDA lesion but Fluvoxamine treatment attenuated these effects. Lipid peroxidation, mRNA levels of IL-1ß, IL-6 and TNF-α were down-regulated while IL-10 and TGF-ß levels were up-regulated in the lesioned striatum of Fluvoxamine treated rats. This study shows that early treatment with Fluvoxamine may attenuate inflammation on injured striatal neurons by favoring anti-inflammatory cytokine expression while decreasing pro-inflammatory cytokine release in the brain. This suggests a role of Fluvoxamine as a potential therapeutic intervention targeting neuronal inflammation associated with PD.
Assuntos
Ansiolíticos/uso terapêutico , Corpo Estriado/patologia , Citocinas/metabolismo , Depressão/tratamento farmacológico , Depressão/etiologia , Fluvoxamina/uso terapêutico , Neurônios/efeitos dos fármacos , Transtornos Parkinsonianos/complicações , Fatores Etários , Animais , Animais Recém-Nascidos , Citocinas/genética , Desipramina/farmacologia , Modelos Animais de Doenças , Lateralidade Funcional , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Neurônios/metabolismo , Oxidopamina/toxicidade , Transtornos Parkinsonianos/induzido quimicamente , Desempenho Psicomotor/efeitos dos fármacos , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Sacarose/administração & dosagemRESUMO
Exposure to early life stress has been shown to result in anxiety-like symptoms and exacerbates degeneration of dopaminergic neurons in a rat model of Parkinson's disease (PD). First line treatment for anxiety disorders includes the use of Fluvoxamine maleate (FM). In this study, we investigated whether treating anxiety-like symptoms with FM has an effect in alleviating the neurotoxic effects of 6-OHDA in a parkinsonian rat model. Early maternal separation was used to create a rat model that depicts anxiety-like symptoms. Maternally separated adult Sprague-Dawley rats were treated with FM prior to and following lesion with 6-hydroxydopamine (6-OHDA). The elevated plus-maze (EPM) and the forelimb akinesia tests were used to evaluate anxiety-like symptoms and motor impairment respectively. Blood plasma was used to measure corticosterone concentration, and striatal tissue was collected for dopamine (DA) and serotonin (5-HT) analysis. Our results show that animals exposed to early life stress displayed increased anxiety-like symptoms and elevated basal plasma corticosterone concentration which were attenuated by treatment with FM. A 6-OHDA lesion effect was evidenced by impairment in the forelimb akinesia test as well as decreased DA and 5-HT concentrations in the lesioned striatum. These effects were attenuated on DA neurons by FM treatment in the pre-lesion treated as opposed to the post-lesion treated rats. This study suggests that early treatment of anxiety-like behavior decreases the vulnerability of DA neurons to neurotoxic insults later in life thus slowing down DA degeneration in PD.
Assuntos
Antiparkinsonianos/uso terapêutico , Ansiedade/tratamento farmacológico , Ansiedade/etiologia , Fluvoxamina/uso terapêutico , Privação Materna , Transtornos Parkinsonianos/tratamento farmacológico , Fatores Etários , Análise de Variância , Animais , Animais Recém-Nascidos , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Membro Anterior/fisiopatologia , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Neurotransmissores/metabolismo , Oxidopamina/toxicidade , Transtornos Parkinsonianos/induzido quimicamente , Gravidez , Ratos , Ratos Sprague-DawleyRESUMO
Early life adversity increases the risk of mental disorders later in life. Chronic early life stress may alter neurotrophic factor gene expression including those for brain derived neurotrophic factor (BDNF) and glial cell derived neurotrophic factor (GDNF) that are important in neuronal growth, survival, and maintenance. Maternal separation was used in this study to model early life stress. Following unilateral injection of a mild dose of 6-hydroxydopamine (6-OHDA), we measured corticosterone (CORT) in the blood and striatum of stressed and nonstressed rats; we also measured DNA methylation and BDNF and GDNF gene expression in the striatum using real time PCR. In the presence of stress, we found that there was increased corticosterone concentration in both blood and striatal tissue. Further to this, we found higher DNA methylation and decreased neurotrophic factor gene expression. 6-OHDA lesion increased neurotrophic factor gene expression in both stressed and nonstressed rats but this increase was higher in the nonstressed rats. Our results suggest that exposure to early postnatal stress increases corticosterone concentration which leads to increased DNA methylation. This effect results in decreased BDNF and GDNF gene expression in the striatum leading to decreased protection against subsequent insults later in life.
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It is estimated that more than 80% of patients with epilepsy live in developing countries with 50-60% of them being children. This high prevalence is perpetuated by low socio-economic challenges, poor health care facilities and lack of drug affordability. Searsia chirindensis formerly known as rhus chirindensis and commonly known as 'Red Current' is a popular traditional medicinal plant, which has been used to treat a number of illnesses such as heart complaints and neurological disorders. The aim of this study is to investigate the effects of S. chirindensis on the development of febrile seizure in a prenatally stressed rat. Febrile seizures were induced by administering lipopolysaccharide to 14-day-old rat pups followed by kainic acid. A subset of the rats was treated with Searsia after induction of febrile seizures. Interleukin-1ß (IL-1ß) levels were measured in plasma. Lipid peroxidation was determined in liver tissue. Our data shows that treatment with Searsia reduced interleukin-1ß levels in plasma of the febrile seizure rats and prevented lipid oxidation in the liver. Prenatal stress is dampened by the beneficial effects of Searsia on seizure development in rat pups. These results highlight the potentiating effects of Searsia in the reversal of febrile seizures and prenatal stress effects.
Assuntos
Anacardiaceae/química , Interleucina-18/sangue , Extratos Vegetais/uso terapêutico , Efeitos Tardios da Exposição Pré-Natal/prevenção & controle , Convulsões Febris/prevenção & controle , Animais , Feminino , Peroxidação de Lipídeos/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal/imunologia , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Ratos Sprague-Dawley , Convulsões Febris/imunologia , Convulsões Febris/metabolismo , Convulsões Febris/fisiopatologia , Estresse PsicológicoRESUMO
D-cycloserine (DCS) has been shown to be effective in facilitating fear extinction in animal and human studies, however the precise mechanisms whereby the co-administration of DCS and behavioural fear extinction reduce fear are still unclear. This study investigated the molecular mechanisms of intrahippocampally administered D-cycloserine in facilitating fear extinction in a contextual fear conditioning animal model. Male Sprague Dawley rats (n = 120) were grouped into four experimental groups (n = 30) based on fear conditioning and intrahippocampal administration of either DCS or saline. The light/dark avoidance test was used to differentiate maladapted (MA) (anxious) from well-adapted (WA) (not anxious) subgroups. RNA extracted from the left dorsal hippocampus was used for RNA sequencing and gene expression data was compared between six fear-conditioned + saline MA (FEAR + SALINE MA) and six fear-conditioned + DCS WA (FEAR + DCS WA) animals. Of the 424 significantly downregulated and 25 significantly upregulated genes identified in the FEAR + DCS WA group compared to the FEAR + SALINE MA group, 121 downregulated and nine upregulated genes were predicted to be relevant to fear conditioning and anxiety and stress-related disorders. The majority of downregulated genes transcribed immune, proinflammatory and oxidative stress systems molecules. These molecules mediate neuroinflammation and cause neuronal damage. DCS also regulated genes involved in learning and memory processes, and genes associated with anxiety, stress-related disorders and co-occurring diseases (e.g., cardiovascular diseases, digestive system diseases and nervous system diseases). Identifying the molecular underpinnings of DCS-mediated fear extinction brings us closer to understanding the process of fear extinction.
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Ciclosserina/farmacologia , Extinção Psicológica/efeitos dos fármacos , Medo/efeitos dos fármacos , RNA/genética , Adaptação Psicológica/efeitos dos fármacos , Animais , Regulação para Baixo/genética , Expressão Gênica/efeitos dos fármacos , Hipocampo , Masculino , Microinjeções , Ratos , Ratos Sprague-Dawley , Análise de Sequência de RNARESUMO
Levo-Dopa (L-Dopa) is widely used for the oral treatment of Parkinson's disease. However, chronic treatment with L-Dopa produces abnormal involuntary movements (AIMs) known as dyskinesias. In this study, commercially available oleanolic acid (OA) that has been previously shown to ameliorate the toxic effects of 6-hydroxydopamine (6-OHDA) in preconditioning studies was used to treat AIMs in a rat model for Parkinson's disease. The forelimb-use asymmetry test was used to measure Parkinson's disease-associated motor impairment. AIMs were measured after 21 days of L-Dopa administration. Glutathione levels were measured in blood, and catalase levels were measured in the substantia nigra and striatum of both the left and right hemispheres. We found that L-Dopa alone as well as L-Dopa and OA combination treatment attenuated the limb-use asymmetry caused by the unilateral injection of 6-OHDA. Chronic L-Dopa administration produced AIMs which were attenuated by treatment with OA. Catalase concentration decreased significantly in the striatum but not in the substantia nigra of the lesioned hemisphere. L-Dopa alone as well as the combined L-Dopa and OA treatment ameliorated the effects of 6-OHDA on catalase concentration. However, intervention with L-Dopa alone as well as with L-Dopa and OA did not affect plasma glutathione concentration. These results suggest that OA administration enhances the effect of catalase on reactive oxygen species following 6-OHDA injection. OA may provide possibilities as an adjunct treatment to prevent or attenuate the development of AIMs following chronic L-Dopa treatment in Parkinson's disease.
Assuntos
Antiparkinsonianos/efeitos adversos , Discinesia Induzida por Medicamentos/tratamento farmacológico , Levodopa/efeitos adversos , Ácido Oleanólico/uso terapêutico , Transtornos Parkinsonianos/tratamento farmacológico , Adrenérgicos/toxicidade , Fatores Etários , Animais , Animais Recém-Nascidos , Catalase/metabolismo , Modelos Animais de Doenças , Discinesia Induzida por Medicamentos/etiologia , Extremidades/fisiopatologia , Feminino , Glutationa/metabolismo , Masculino , Movimento/efeitos dos fármacos , Oxidopamina/toxicidade , Transtornos Parkinsonianos/induzido quimicamente , Gravidez , Ratos , Ratos Sprague-Dawley , Estatísticas não ParamétricasRESUMO
Oleanolic acid is a triterpenoid that has been shown to possess antioxidant properties. In this study we investigated the effects of oleanolic acid in a parkinsonian rat model. Unilateral 6-hydroxydopamine (6-OHDA) lesions were carried out on postnatal day (PND) 60 in 4 groups viz. (1) Rats that started oleanolic acid treatment 7 days prior to lesion. (2) Rats not treated with oleanolic acid. (3) Rats that started oleanolic acid treatment 1 day post-lesion. (4) Rats treated with oleanolic acid 7 days post-lesion. The degree of forelimb impairment was assessed using limb use asymmetry and forelimb akinesia tests. Neurochemical changes were assessed using a Dopamine ELISA kit and mitochondrial apoptosis was measured using a mitochondrial apoptosis detection kit. In this study, animals injected with 6-OHDA displayed forelimb use asymmetry that was ameliorated by treatment with oleanolic acid 7 days pre- and 1 day post-lesion. In the cylinder test, rats injected with 6-OHDA favored using the forelimb ipsilateral (unimpaired) to the lesioned hemisphere while rats treated with oleanolic acid used the forelimb contralateral (impaired) to the lesioned hemisphere significantly more. Rats treated with oleanolic acid 7 days pre- and 1 day post-lesion had more dopamine in the striatum than the non-treated or the 7 days after lesion rats. Similarly, 6-OHDA-induced membrane depolarization was decreased in rats that received oleanolic acid treatment pre- or immediately post-lesion. This suggests that early treatment with oleanolic acid protects dopamine neurons from the toxic effects of 6-OHDA.
Assuntos
Antiparkinsonianos/farmacologia , Corpo Estriado/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Ácido Oleanólico/farmacologia , Transtornos Parkinsonianos/tratamento farmacológico , Animais , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Corpo Estriado/patologia , Corpo Estriado/fisiopatologia , Dopamina/metabolismo , Membro Anterior/fisiopatologia , Lateralidade Funcional , Masculino , Feixe Prosencefálico Mediano , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Mitocôndrias/fisiologia , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Degeneração Neural/tratamento farmacológico , Degeneração Neural/patologia , Degeneração Neural/fisiopatologia , Oxidopamina , Transtornos Parkinsonianos/patologia , Transtornos Parkinsonianos/fisiopatologia , Ratos Sprague-Dawley , Fatores de Tempo , Resultado do TratamentoRESUMO
Preconditioning triggers endogenous protection against subsequent exposure to higher concentrations of a neurotoxin. In this study, we investigated whether exposure to oleanolic acid (OA) enhances the protective effects of preconditioning on PC12 cells exposed to 6-hydroxydopamine (6-OHDA). A concentration response curve was constructed using 6-OHDA (50, 150, 300, and 600 µM). The experiment consisted of 6 groups: untreated, OA only, Group 1: cells treated with 6-OHDA (50 µM) for 1 hour, Group 2: cells treated with 6-OHDA (150 µM) for 1 hour, Group 3: cells treated with 6-OHDA (50 µM) for 30 minutes followed 6 hours later by treatment with 6-OHDA (150 µM) for 30 minutes, and Group 4: cells treated as in group 3 but also received OA immediately after the second 6-OHDA treatment. Cell viability and apoptotic ratio were assessed using the MTT and Annexin V staining tests, respectively. In preconditioned cells, we found that cell viability remained high following exposure to 6-OHDA (150 µM). OA treatment enhanced the protective effects of preconditioning. Similarly, with the annexin V apoptosis test, preconditioning protected the cell and this was enhanced by OA. Therefore, preexposure of PC12 cells to low 6-OHDA concentration can protect against subsequent toxic insults of 6-OHDA and OA enhances this protection.
RESUMO
Methylmercury (MeHg) is a metal toxin found commonly in the environment. Studies have shown severe neurotoxic effects of MeHg poisoning especially during pregnancy where it crosses the foetoplacental and the blood brain barrier of the foetus leading to neurodevelopmental deficits in the offspring. These deficits may predispose offspring to neurodegenerative diseases later in life. In this study we investigated the effects of prenatal methylmercury exposure (2.5 mg/L in drinking water from GND 1-GND 21) on the trace element status in the brain of adolescent offspring (PND 28). Total antioxidant capacity (TAC) was measured in their blood plasma. In a separate group of animals that was also exposed prenatally to MeHg, 6-hydroydopamine (6-OHDA) was administered at PND 60 as a model of neuronal insult. Trace element and TAC levels were compared before and after 6-OHDA exposure. Prenatal MeHg treatment alone resulted in significantly higher concentrations of zinc, copper, manganese and selenium in the brain of offspring at PND 28 (p < 0.05), when compared to controls. In contrast, brain iron levels in MeHg-exposed adolescent offspring were significantly lower than their controls (p < 0.05). Following 6-OHDA exposure, the levels of iron, zinc, copper and manganese were increased compared to sham-lesioned offspring (p < 0.05). Prenatal MeHg exposure further increased these trace element levels thereby promoting toxicity (p < 0.05). Total antioxidant capacity was not significantly different in MeHg and control groups prior to lesion. However, following 6-OHDA administration, MeHg-exposed animals had a significantly lower TAC than that of controls (p < 0.05). Brain TAC levels were higher in adult male rats than in female rats during adolescence however male rats that had been exposed to MeHg in utero failed to show this increase at PND 74. Prenatal MeHg exposure results in trace element dyshomeostasis in the brain of offspring and reduces total antioxidant capacity. This may reflect a mechanism by which methylmercury exerts its neurotoxicity and/or predispose offspring to further neurological insults during adulthood.
Assuntos
Antioxidantes/metabolismo , Compostos de Metilmercúrio/toxicidade , Neurônios/metabolismo , Oxidopamina/toxicidade , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Oligoelementos/metabolismo , Animais , Biomarcadores/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Feminino , Masculino , Neurônios/efeitos dos fármacos , Gravidez , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Ratos , Ratos Sprague-DawleyRESUMO
BACKGROUND: In Cameroonian traditional medicine various extracts of Gladiolus dalenii Van Geel (Iridaceae) have been used as a cure for various ailments that include headaches, digestive problems, muscle and joint aches, and some central nervous system disorders such as epilepsy, schizophrenia and mood disorders. Owning to this background, the aim of the study was to investigate whether an aqueous macerate of the bulb of Gladiolus dalenii has any antidepressant activity focusing specifically on depression-like behaviours associated with epilepsy. METHOD: We used the combined administration of atropine and pilocarpine to rats as our animal model of epilepsy. The forced swim test and spontaneous locomotor activity in the open field test were the two tools used to assess the presence of depression-like behaviour in epileptic and control animals. The following depression-related parameters were determined: plasma ACTH, plasma corticosterone, adrenal gland weight and hippocampal levels of brain-derived neurotrophic factor (BDNF). The effects of Gladiolus dalenii were compared to that of fluoxetine. RESULTS: Our results showed that we had a valid animal model of epilepsy-induced depression as all 3 measures of construct, predictive and face validity were satisfied. The data indicated that Gladiolus dalenii significantly reduced the immobility times in the forced swim test and the locomotor activity as assessed in the open field. A similar pattern was observed when the HPA axis parameters were analysed. Gladiolus dalenii significantly reduced the levels of ACTH, corticosterone, but not the adrenal gland weight. Gladiolus dalenii significantly increased the level of BDNF in the hippocampus. In all parameters measured the effects of Gladiolus dalenii were significantly greater than those of fluoxetine. CONCLUSION: The results show that Gladiolus dalenii has antidepressant-like properties similar to those of fluoxetine in epilepsy-associated depressive states. The antidepressant activity of Gladiolus dalenii is likely to be mediated by restoring the activity of the HPA axis and increasing the levels of BDNF in the hippocampus.
Assuntos
Antidepressivos/administração & dosagem , Depressão/tratamento farmacológico , Epilepsia/complicações , Iridaceae/química , Animais , Fator Neurotrófico Derivado do Encéfalo/sangue , Corticosterona/sangue , Depressão/sangue , Depressão/etiologia , Depressão/genética , Flores/química , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Humanos , Sistema Hipotálamo-Hipofisário , Masculino , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Sistema Hipófise-Suprarrenal/metabolismo , Ratos , Ratos WistarRESUMO
The HIV-1 transactivator protein tat is pivotal to the pathogenesis of AIDS, exerting its effects on both viral and cellular gene expression. The basic structure of tat protein allows it to be secreted by HIV-1 infected cells and penetrate uninfected cells where it elicits its multifunctional biochemical effects. The main function of tat protein is viral transactivation which leads to the upregulation of transcription through complex interactions with RNA and host cell factors. Since HIV-1 has been widely implicated as a causative agent of HIV-1 dementia, the aim of our study was to investigate the ability of two novel metal chelators, fusaric acid (FA) and picolinic acid (PA) to firstly inhibit HIV-1 tat induced transcription and secondly, to minimize its cytotoxic effects as mediated via apoptosis. Biologically active tat protein is not freely available commercially. We therefore had to produce, isolate and purify our own protein. A cell culture system and flow cytometric techniques were used in our study. Exposure of CEM-GFP cells to exogenous recombinant tat protein induced transcription and apoptosis, and both processes were inhibited by FA and PA at concentrations that alone did not induce any cytotoxicity. Our data suggest that FA and PA may have therapeutic potential in the management of HIV-1 dementia.
Assuntos
Complexo AIDS Demência/genética , Apoptose/efeitos dos fármacos , Quelantes/farmacologia , HIV-1 , Metais/metabolismo , Ativação Transcricional/efeitos dos fármacos , Produtos do Gene tat do Vírus da Imunodeficiência Humana/antagonistas & inibidores , Complexo AIDS Demência/tratamento farmacológico , Complexo AIDS Demência/virologia , Células Cultivadas , Citometria de Fluxo , Ácido Fusárico/farmacologia , Humanos , Ácidos Picolínicos/farmacologia , Produtos do Gene tat do Vírus da Imunodeficiência Humana/metabolismoRESUMO
A febrile seizure is a neurological disorder that occurs following an infection that results in a rapid rise in body temperature. It commonly affects 3-5% of children between the ages of 3 months and 5 years. Interleukin-1 beta IL-1ß a pro-inflammatory cytokine has been suggested to play a role in the manifestation of febrile seizures. There is evidence suggesting that neurological disorders can be exacerbated in an offspring that was exposed to stress prenatally. The aim of our study was therefore to investigate whether febrile seizures are exacerbated in the offspring of rats that were prenatally stressed. The offspring of pregnant Sprague-Dawley dams were used in the study. Prenatal stress consisted of exposing the pregnant dams to 45 min of restraint, 3 times per day with 3 h intervals in-between, for 7 days starting on gestational day 14 (GND14). On postnatal day (PND) 14, the pups were injected with lipopolysaccharide (LPS, 200 µg/kg, i.p.) followed 2.5 h later by an i.p. injection of kainic acid (KA, 1.75 mg/kg). All the animals were decapitated on PND 21. Trunk blood was collected to detect plasma interleukin-1beta (IL-1ß) levels in the various groups. Our data showed that i.p. injections of LPS followed by KA led to the development of seizure activity that was associated with increased plasma IL-1ß levels. Prior exposure to prenatal stress resulted in the development of advanced stages of seizure development, leading to an exaggerated seizure response. Prenatal stress alone also led to elevated plasma IL-1ß levels, while previously stressed animals receiving LPS and KA yielded the highest plasma levels of IL-1ß levels. Our data therefore shows that IL-1ß levels may play an important role in the development of febrile seizures.
Assuntos
Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Convulsões Febris/induzido quimicamente , Convulsões Febris/fisiopatologia , Estresse Psicológico/fisiopatologia , Animais , Animais Recém-Nascidos , Modelos Animais de Doenças , Feminino , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Ratos , Ratos Sprague-Dawley , Restrição Física , Convulsões Febris/complicações , Estresse Psicológico/sangue , Estresse Psicológico/complicaçõesRESUMO
Methamphetamine is a highly addictive stimulant drug whose illicit use and resultant addiction has become an alarming global phenomenon. The mesolimbic dopaminergic pathway has been shown to be fundamental to the establishment of addictive behaviour. This pathway, as part of the reward system of the brain, has also been shown to be important in classical conditioning, which is a learnt response. Within the modulation of learning and memory, the neurohypophyseal hormones vasopressin and oxytocin have been reported to play a vital role, with vasopressin exerting a long- term facilitatory effect and oxytocin exerting an inhibitory effect. Therefore we adopted a conditioned place preference model to investigate whether vasopressin V1b receptor antagonist SSR 149415 or oxytocin treatment would cause a decrease in the seeking behaviour in a reinstatement paradigm. Behavioural findings indicated that methamphetamine induced a change in the place preference in the majority of our animals. This change in place preference was not seen when vasopressin was administered during the extinction phase. On the other hand the methamphetamine-induced change in place preference was enhanced during the reinstatement phase in the animals that were treated with oxytocin. Striatal dopamine levels were determined, as methamphetamine is known to increase dopamine transmission in this area. Significant changes in dopamine levels were observed in some of our animals. Rats that received both methamphetamine and oxytocin had significantly higher striatal dopamine than those that received oxytocin alone. Western blot analysis for hippocampal cyclic AMP response element binding protein (CREB) was also conducted as a possible indicator of glutamatergic NMDA receptor activity, a pathway that is important for learning and memory. The Western blot analysis showed no changes in hippocampal pCREB expression. Overall our data led us to conclude that methamphetamine treatment can change place preference behaviour in rats and that this change may be partially restored by vasopressin antagonism, but exaggerated by oxytocin.
Assuntos
Transtornos Relacionados ao Uso de Anfetaminas/tratamento farmacológico , Metanfetamina/antagonistas & inibidores , Ocitocina/farmacologia , Vasopressinas/farmacologia , Transtornos Relacionados ao Uso de Anfetaminas/metabolismo , Transtornos Relacionados ao Uso de Anfetaminas/fisiopatologia , Animais , Estimulantes do Sistema Nervoso Central/antagonistas & inibidores , Estimulantes do Sistema Nervoso Central/toxicidade , Modelos Animais de Doenças , Masculino , Metanfetamina/toxicidade , Ocitocina/fisiologia , Ratos , Ratos Sprague-Dawley , Vasopressinas/antagonistas & inibidores , Vasopressinas/fisiologiaRESUMO
Many studies have reported on the detrimental effects of early life adversity and the beneficial effects of exercise on brain function. However, the molecular mechanisms that underpin these various effects remain poorly understood. The advent of advanced proteomic analysis techniques has enabled simultaneous measurement of protein expression in a wide range of biological systems. We therefore used iTRAQ proteomic analysis of protein expression to determine whether exercise counteracts the detrimental effects of early life adversity in the form of maternal separation on protein expression in the brain. Rat pups were subjected to maternal separation from postnatal day 2 to 14 for 3 h day(-1) or normally reared. At 40 days of age, half of the rats in each group (maternal separation and normally reared) were allowed to exercise voluntarily (access to a running wheel) for 6 weeks and the remainder kept as sedentary control animals. At 83 days of age, rats were killed and the ventral hippocampus was dissected for quantitative proteomic (iTRAQ) analysis. The iTRAQ proteomic analysis identified several proteins that had been altered by maternal separation, including proteins involved in neuronal structure, metabolism, signalling, anti-oxidative stress and neurotransmission, and that many of these proteins were restored to normal by subsequent exposure to voluntary exercise in adolescence. Our data show that a broad range of proteins play a role in the complex consequences of adversity and exercise.