392 resultados para cortico-striatal
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O macaco-prego, Cebus apella, é muito difundido no norte e sul da Amazônia Legal Brasileira e no Cerrado. Estes animais encontram-se rotineiramente submetidos à caça predatória, aumentando assim a necessidade de preservação desta espécie silvestre. Realizou-se um estudo ultra-sonográfico de 10 macacos-prego como forma de descrever a anatomia ultra-sonográfica normal de sua cavidade abdominal. A vesícula urinária apresentou parede com espessura média 0,2cm e em posição anatômica cuja topografia permitiu contato com as paredes do corpo do útero e cólon descendente. À varredura abdominal caudal foi visualizada a aorta, veia cava caudal e veia ilíaca direita. O fígado foi visto em varredura sagital e transversal, possibilitando a observação da vesícula biliar e vasos hepáticos. A varredura renal demonstrou com precisão a pelve, seio renal e relação cortico-medular. O comprimento médio de ambos os rins foi de 6,24±0,31cm, não existindo diferença estatística entre o rim direito e esquerdo (Teste t de Student e ANOVA). O volume renal foi 2,37±0,18cm³. Os coeficientes de Correlação de Pearson entre os comprimentos renais direito e esquerdo e entre volumes renais direito e esquerdo foram dispostos como r = 0,74 e 0,51. As espessuras médias para a região cortical e medular foram 0,75±0,11cm e 0,39±0,06cm, respectivamente. O coeficiente de correlação para a relação cortico-medular entre os rins direito e esquerdo foi de r = 0,19. O exame ultrasonográfico mostrou-se como uma técnica eficiente, nãoinvasiva, rápida e reprodutível, que provê dados importantes aos profissionais da área de clínica e cirurgia de animais silvestres.
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The present study investigated the effects of intranigral MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) infusion on rats treated with phosphatidylserine and evaluated in two memory tasks and on striatal dopamine levels. The results indicated that MPTP produced a significant decrease in the avoidance number in comparison to sham-operated and non-operated rats submitted to a two-way avoidance task. MPTP-lesioned rats exhibited an increase in the latencies to find the platform in cued version of the water maze in comparison to sham-operated and non-operated animals. The tested toxin reduced striatal dopamine levels in comparison to sham-operated and non-operated groups. A final surprising result was that phosphatidylserine was unable to reverse the cognitive deficits produced by MPTP or the reduction of striatal dopamine levels. In conclusion, the data suggest that MPTP is a good model to study the early impairment associated with Parkinson's disease and phosphatidylserine did not improve the memory impairment induced by MPTP. (C) 2003 Elsevier B.V. All rights reserved.
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The effects of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) on the central nervous system (CNS) were studied in rats. Behavioural and neurochemical studies were performed. Results show that acute and oral administration of dimethylamine 2,4-D was able to decrease locomotion and rearing frequencies and to increase immobility duration of rats observed in an open-field test. Treatment of rats with p-chlorophenylalanine (PCPA) was unable to change rat's open-field behaviour; 5-hydroxytryptophan (5-HTP) administration not only increased locomotion and rearing frequences but also decreased immobility duration. Pretreatment of the rats with PCPA and 5-HTP decreased and increased dimethylamine 2,4-D effects, respectively. The herbicide was not able to change the striatal levels of dopamine and homovanilic acid but decreased the striatal levels of serotonin (5-HT), as observed for the doses of 100 and 200 mg/kg and increased those of 5-hydroxyindoleacetic acid (5-HIAA) as measured after the 200 mg/kg dose treatment. When the levels of serotonin and 5-HIAA were measured at the brain stem level, only those of 5-HIAA were modified, being increased by diethylamine 2,4-D (60; 100 and 200 mg/kg); this increment on 5-HIAA levels was observed even 1 hr after pesticide administration. Further analysis showed that 2,4-D concentrations chromatographycally detected both in serum and brain of the intoxicated animals were dose-dependent, being found as early as 1 hr after the smaller dose of the herbicide used (10 mg/kg). The results suggest that diethylamine 2,4-D modify 5-HT functional activity within the CNS. Thus, the effects of the herbicide on open-field behaviour of rats could be attributed to a direct or indirect pesticide action on serotoninergic systems.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The literature has already demonstrated that auditory stimulation with music influences the cardiovascular system. In this study, we performed a literature review in order to investigate the relationship between auditory mechanisms and cardiac autonomic regulation. The selected studies indicated that there is a strong correlation between noise intensity and vagal-sympathetic balance. Also, it was reported that music therapy improved heart rate variability in anthracycline-treated breast cancer patients. It was hypothesized that dopamine release in the striatal system induced by pleasure songs are involved in the cardiac autonomic regulation. Further studies are necessary to add new elements in the literature to improve new therapies to treat cardiovascular disorders.
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In this article, the authors aim to present a critical review of recent MRI studies addressing white matter (WM) abnormalities in Alzheimer's disease (AD) and mild cognitive impairment (MCI), by searching PubMed and reviewing MRI studies evaluating subjects with AD or MCI using WM volumetric methods, diffusion tensor imaging and assessment of WM hyperintensities. Studies have found that, compared with healthy controls, AD and MCI samples display WM volumetric reductions and diffusion tensor imaging findings suggestive of reduced WM integrity. These changes affect complex networks relevant to episodic memory and other cognitive processes, including fiber connections that directly link medial temporal structures and the corpus callosum. Abnormalities in cortico-cortical and cortico-subcortical WM interconnections are associated with an increased risk of progression from MCI to dementia. It can be concluded that WM abnormalities are detectable in early stages of AD and MCI. Degeneration of WM networks causes disconnection among neural cells and the degree of such changes is related to cognitive decline. © 2013 2013 Expert Reviews Ltd.
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Pós-graduação em Odontologia - FOAR
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O objetivo desta investigação foi avaliar o padrão degenerativo de diversos tratos de substância branca após lesão isquêmica estriatal, correlacionando o processo degenerativo com os padrões de ativação microglial e expressão de Nogo-A. Para isso, foi induzida isquemia focal com injeção estereotáxica de endotelina no estriado de ratos adultos, e nos animais controle apenas injetou-se solução salina estéril. Os animais foram perfundidos 3, 7, 14 e 30 dias após isquemia. O cérebro removido, pós-fixado, crioprotegido, cortado em criostato e os cortes obtidos submetidos à investigação imunoistoquímica com os seguintes anticorpos: Anti-GFAP (1:2000,Dako), Anti-Tau-1 (1:500,Chemicon), Anti-MBP (1:100,Chemicon International), Anti-Nogo A (1:100,Invitrogen), Anti-Iba1 (1:1000, WAKO), Anti-ED1 (1:500, Serotec) e Anti-MHC-II (1:100 Abcam), além da visualização do padrão lesivo com violeta de cresila. As lâminas marcadas pelos diferentes métodos foram avaliadas qualitativamente e algumas também quantitativamente (Anti-Nogo A, Anti-ED1, Anti-MHC-II e Anti-Tau-1), com contagens realizadas no estriado e no corpo caloso. Os dados foram tabulados, submetidos à análise estatística pelo teste de Tukey (p<0,05) e capturadas micrografias dos achados mais representativos. As lâminas coradas com violeta de cresila revelaram um aumento da densidade celular pela infiltração de células inflamatórias à área isquêmica, com aumento expressivo ao 7º dia. Nas lâminas imunomarcadas para GFAP foi encontrado aumento progressivo da população de astrócitos, assim como um aumento do volume celular em 7 e 14 dias. Oligondendrócitos patológicos marcados com Tau-1 tiveram pico de marcação ao 3º dia no estriado e ao 7º dia no corpo caloso, e a perda de compactação de mielina identificada pelo MBP foi melhor observada ao 14º dia, nos diferentes tratos. A ativação microglial identificada pelas diferentes imunomarcações apresentou seu pico ao 7º dia, tanto em estriado como em corpo caloso, porém no corpo caloso com um número muito menor quando comparado com o estriado. A morfologia microglial sofreu variações, sendo encontrado o fenótipo ramificado nos animais controles, assim como nos tempos precoces e tardios pós isquemia e o padrão amebóide/fagocítico ao 7º dia, coincidente com o maior número de células ativadas. A contagem de células Nogo-A + teve seu pico observado ao 3º dia no estriado, não sendo observadas no corpo caloso diferenças de expressão de Nogo-A entre 3 a 14 dias, apenas uma diminuição quando comparado a 30 dias. Sendo assim, microinjeções de ET-1 no estriado induziram conspícua perda tecidual, concomitante com ativação microglial progressiva, astrocitose, perda da imunoreatividade para proteína básica de mielina e lesão de oligodendrócitos em diversos tempos de sobrevida após isquemia focal. Estes eventos acometem alguns tratos de SB, como o corpo caloso. O estabelecimento da evolução temporal destes eventos neuropatológico é a base para estudos futuros, nos quais se deverá manipular a resposta inflamatória com intuito de minimizar estas alterações teciduais.
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A doença de Parkinson (DP) é a segunda doença neurodegenerativa mais comum em idosos, caracterizada pela neurodegeneração de neurônios dopaminérgicos da substância negra (SN), com etiologia não claramente estabelecida, entretanto as causas podem estar associadas a exposição de toxinas ambientais e fatores genéticos. Os processos patológicos envolvidos na DP são disfunção mitocondrial, estresse oxidativo, inflamação e excitotoxicidade. A sintomatologia da DP são alterações motoras, cognitivas e autonômicas. Contudo, poucos estudos analisam os sintomas não-motores da DP, principalmente em modelos animais. Nesse contexto o objetivo deste trabalho foi avaliar sintomas não-motores da DP em modelo animal com lesão provocada pela neurotoxina 6-hidroxidopamina com duas doses diferentes, injetadas bilateralmente no estriado. Para alcançar nossos objetivos realizamos os testes de campo aberto, apomorfina, labirinto aquático de Morris e testes de discriminação olfativa, além de análises histológicas. Nossos resultados mostraram alterações motoras, déficits de memória e aprendizado, associadas a diminuição de células dopaminérgicas na SN, neurônios estriatais e neurônios da região hipocampal CA1. Dessa forma, esse modelo para os sintomas não-motores da DP pode ser utilizado para a compreensão dos mecanismos que envolvem a doença, assim como para avaliar medidas terapêuticas que possam retardar ou interromper a progressão da DP.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The aim of the present study was to evaluate the behavioral patterns associated with autism and the prevalence of these behaviors in males and females, to verify whether our model of lipopolysaccharide (LPS) administration represents an experimental model of autism. For this, we prenatally exposed Wistar rats to LPS (100 mu g/kg, intraperitoneally, on gestational day 9.5), which mimics infection by gram-negative bacteria. Furthermore, because the exact mechanisms by which autism develops are still unknown, we investigated the neurological mechanisms that might underlie the behavioral alterations that were observed. Because we previously had demonstrated that prenatal LPS decreases striatal dopamine (DA) and metabolite levels, the striatal dopaminergic system (tyrosine hydroxylase [TH] and DA receptors D1a and D2) and glial cells (astrocytes and microglia) were analyzed by using immunohistochemistry, immunoblotting, and real-time PCR. Our results show that prenatal LPS exposure impaired communication (ultrasonic vocalizations) in male pups and learning and memory (T-maze spontaneous alternation) in male adults, as well as inducing repetitive/restricted behavior, but did not change social interactions in either infancy (play behavior) or adulthood in females. Moreover, although the expression of DA receptors was unchanged, the experimental animals exhibited reduced striatal TH levels, indicating that reduced DA synthesis impaired the striatal dopaminergic system. The expression of glial cell markers was not increased, which suggests that prenatal LPS did not induce permanent neuroinflammation in the striatum. Together with our previous finding of social impairments in males, the present findings demonstrate that prenatal LPS induced autism-like effects and also a hypoactivation of the dopaminergic system. (c) 2012 Wiley Periodicals, Inc.
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Serotonin reuptake inhibitors and cognitive-behavior therapy (CBT) are considered first-line treatments for obsessive-compulsive disorder (OCD). However, little is known about their modulatory effects on regional brain morphology in OCD patients. We sought to document structural brain abnormalities in treatment-naive OCD patients and to determine the effects of pharmacological and cognitive-behavioral treatments on regional brain volumes. Treatment-naive patients with OCD (n = 38) underwent structural magnetic resonance imaging scan before and after a 12-week randomized clinical trial with either fluoxetine or group CBT. Matched-healthy controls (n = 36) were also scanned at baseline. Voxel-based morphometry was used to compare regional gray matter (GM) volumes of regions of interest (ROIs) placed in the orbitofrontal, anterior cingulate and temporolimbic cortices, striatum, and thalamus. Treatment-naive OCD patients presented smaller GM volume in the left putamen, bilateral medial orbitofrontal, and left anterior cingulate cortices than did controls (p<0.05, corrected for multiple comparisons). After treatment with either fluoxetine or CBT (n = 26), GM volume abnormalities in the left putamen were no longer detectable relative to controls. ROI-based within-group comparisons revealed that GM volume in the left putamen significantly increased (p<0.012) in fluoxetine-treated patients (n = 13), whereas no significant GM volume changes were observed in CBT-treated patients (n = 13). This study supports the involvement of orbitofronto/cingulo-striatal loops in the pathophysiology of OCD and suggests that fluoxetine and CBT may have distinct neurobiological mechanisms of action. Neuropsychopharmacology (2012) 37, 734-745; doi: 10.1038/npp.2011.250; published online 26 October 2011
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The ether A go-go (Eag) gene encodes the voltage-gated potassium (K+) ion channel Kv10.1, whose function still remains unknown. As dopamine may directly affect K+ channels, we evaluated whether a nigrostriatal dopaminergic lesion induced by the neurotoxin 6-hydroxydopamine (6-OHDA) would alter Eag1-K+ channel expression in the rat basal ganglia and related brain regions. Male Wistar rats received a microinjection of either saline or 6-OHDA (unilaterally) into the medial forebrain bundle. The extent of the dopaminergic lesion induced by 6-OHDA was evaluated by apomorphine-induced rotational behavior and by tyrosine hydroxylase (TH) immunoreactivity. The 6-OHDA microinjection caused a partial or complete lesion of dopaminergic cells, as well as a reduction of Eag1+ cells in a manner proportional to the extent of the lesion. In addition, we observed a decrease in TH immunoreactivity in the ipsilateral striatum. In conclusion, the expression of the Eag1-K+-channel throughout the nigrostriatal pathway in the rat brain, its co-localization with dopaminergic cells and its reduction mirroring the extent of the lesion highlight a physiological circuitry where the functional role of this channel can be investigated. The Eag1-K+ channel expression in dopaminergic cells suggests that these channels are part of the diversified group of ion channels that generate and maintain the electrophysiological activity pattern of dopaminergic midbrain neurons.