INTRODUÇÃO: Injeções intravítreas de acetato de triancinolona são utilizadas no tratamento de uma série de doenças retinianas. Estudos in vitro demonstram toxicidade, mas não está ainda claro se está relacionada ao preservativo ácido benzílico. Recentemente, uma formulação sem preservativo (Triesence®) foi aprovada nos Estados Unidos da América para uso intraocular. Entretanto, não existem estudos avaliando os efeitos in vitro e in vivo desta formulação. OBJETIVOS: Avaliar os efeitos do Triesence® em culturas de células retinianas e em um modelo experimental animal. MÉTODOS: As culturas de células ARPE-­-19 e R28 foram tratadas por 24 horas com Triesence® em cristais (TRIc) nas doses de 1000, 500, 200 ou 100 g/mL, ou solubilizado (TRIs) nas doses de 1000, 500 ou 200 ?g/mL. O Triesence® foi solubilizado após a centrifugação da droga, descarte do sobrenadante contendo o veículo, e em seguida ressuspensão da droga em quantidade equivalente de dimetilsulfóxido (DMSO). A porcentagem de viabilidade celular (VC) foi avaliada em ensaio de exclusão com azul de tripan. O potencial de membrana mitocondrial, foi analisado com o ensaio JC1. A atividade da caspase-­-3/7 foi mensurada por ensaio com fluoróforos. Trinta coelhos borboletas (Oryctolagus Cuniculum) foram divididos em três grupos e receberam 3 quantidades diferentes de Triesence® intravítreo: 1, 4, ou 8 mg. Após a anestesia, o olho direito (OD) recebeu a droga, enquanto o olho esquerdo (OE) recebeu o mesmo volume de solução salina balanceada. Ao final de 30 dias, o eletrorretinograma (ERG) foi registrado. Após realização do ERG, os animais foram sacrificados e os olhos coletados para análise morfológica. Doze outros coelhos foram submetidos somente a análise morfológica após 7 dias da aplicação. OS ERGs foram registrados com o sistema RETIport (Roland Consult, Alemanha), com um estimulador Ganzfeld Q450 SC. O teste de postos com sinais de Wilcoxon foi utilizado para comparar as amostras relacionadas. Para estímulos escotópicos, o valor logarítmico das amplitudes médias da onda b foi relacionado ao valor logarítmico da intensidade luminosa de cada estímulo, e a amplitude máxima da onda b (Vmax), a intensidade luminosa necessária para se atingir 50% do valor do Vmax (k), e a inclinação da curva (n) foram analisados utilizando-­-se os testes estatísticos ANOVA e t de Student pareado bicaudal. Resumo RESULTADOS: TRIc causa diminuição significativa na viabilidade celular em todas as concentrações e linhagens testadas, o que é minimizado pela solubilização da droga. Mesmo o TRIs demonstrou aumento da regulação da caspase 3/7, indicativo de apoptose in vitro, mas não houve aumento da atividade no ensaio JC1. O ERG escotópico evidenciou uma queda estatisticamente significativa de aproximadamente 7% no Vmax no grupo recebendo 8 mg a droga, mas não houve alteração significativa nos parâmetros k ou n em nenhuma concentração testada. O ERG fotópico evidenciou amplitudes de onda b significativamente reduzidas nos grupos que receberam 4 ou 8 mg, mas não no que recebeu 1 mg. Observou-­-se redução na amplitude do flicker para 24 ou 30 Hertz (Hz) no grupo que recebeu 8 mg, e para 30 Hz no grupo que recebeu 4 mg. Não foram notadas diferenças nos ensaios Hematoxilina-­-Eosina (H&E), Tunnel, Fluoro-­-Jade B ou GFAP (proteína glial fibrilar ácida) entre retinas tratadas e controle após 30 dias. Entretanto, após 7 dias, observou-­-se marcação positiva para proteína glial fibrilar ácida nas células de Müller. CONCLUSÃO: TRIc causa uma diminuição significativa na viabilidade celular em culturas de células retinianas. Após solubilizada, a droga não causa este efeito ou tampouco altera-o. Mesmo o TRIs causa aumento dos níveis de caspase 3/7, sugerindo apoptose. No modelo experimental em coelhos, foram observadas alterações morfológicas e eletrorretinográficas após a injeção intravítrea de Triesence®. Células de Müller apresentaram expressão de GFAP após 7 dias, mas não após 30 dias, sugerindo ativação transitória deste tipo celular. Não foram encontrados sinais de necrose ou apoptose, mesmo nas doses mais elevadas. Os resultados do ERG sugerem toxicidade retiniana após aplicação intravítrea de 4 ou 8 mg de Triesence® (4 a 8 vezes a dose clínica terapêutica) / INTRODUCTION: Intravitreous triancinolone acetonide is used to treat various retinal disorders. In vitro studies show toxicity, but it is not clear if that is related to the preservative benzyl alcohol. Recently, a formulation without preservative (Triesence®) was approved for intraocular use. However, no in vitro or in vivo studies with this formulation have been reported in literature so far. OBJECTIVES: To evaluate the effects of the exposure of Triesence® on retinal cells in culture and on an in-­-vivo rabbit model. METHODS: ARPE-­-19 and R28 cell cultures were treated for 24 hours with 1000, 500, 200 or 100 ?g/mL of crystalline (TRIc) or 1000, 500 or 200 g/mL of solubilized (TRIs) Triesence®. The drug was solubilized by centrifuging it, discarding the supernatant containing the vehicle and then resuspending the pellet in an equivalent amount of Dimethyl sulfoxide (DMSO). Percentage of cell viability (VC) was evaluated by a trypan blue dye-­-exclusion assay. The mitochondrial membrane potential was analyzed with the JC-­-1 assay. The caspase-­-3/7 activity was measured by a fluorochrome assay. Thirty pigmented rabbits (Oryctolagus Cuniculum) were assigned to 3 different intravitreal drug concentrations of Triesence®: 1, 4 or 8 mg. The animals were anesthetized and the right eye (OD) received drug, while the left eye (OS) received balanced salt solution. After 30 days, electroretinogram (ERG) was recorded. ERGs were recorded with the RETIport system (Roland Consult, Germany) with a Ganzfeld Q450 SC stimulator. Wilcoxon signed rank test was used to compare related samples. After the ERG, the animals were euthanized and the eyes were collected for morphological analysis. Twelve other rabbits had histology only analysis after 7 days of injection. Dark-­-adapted b-­-wave mean amplitudes were plotted as log response versus log light intensity curves, and the maximum The mitochondrial membrane potential was analyzed with the JC-­-1 assay. The caspase-­-3/7 activity was measured by a fluorochrome assay. Thirty pigmented rabbits (Oryctolagus Cuniculum) were assigned to 3 different intravitreal drug concentrations of Triesence®: 1, 4 or 8 mg. The animals were anesthetized and the right eye (OD) received drug, while the left eye (OS) received balanced salt solution. After 30 days, electroretinogram (ERG) was recorded. ERGs were recorded with the RETIport system (Roland Consult, Germany) with a Ganzfeld Q450 SC stimulator. Wilcoxon signed rank test was used to compare related samples. After the ERG, the animals were euthanized and the eyes were collected for morphological analysis. Twelve other rabbits had histology only analysis after 7 days of injection. Dark-­-adapted b-­-wave mean amplitudes were plotted as log response versus log light intensity curves, and the maximum

L'un des enjeux majeurs actuellement en neurosciences est l'élaboration de modèles computationnels capables de reproduire les données obtenues expérimentalement par des méthodes d'imagerie et permettant l'étude de la relation structure-fonction dans le cerveau. Les travaux de modélisation dans cette thèse se situent à deux échelles et l'analyse des modèles a nécessité le développement d'outils théoriques et numériques dédiés. À l'échelle locale, nous avons proposé un nouveau modèle d'équations différentielles ordinaires générant des activités neuronales, caractérisé et classifié l'ensemble des comportements générés, comparé les sorties du modèle avec des données expérimentales et identifié les structures dynamiques sous-tendant la génération de comportements pathologiques. Ce modèle a ensuite été couplé bilatéralement à un nouveau compartiment modélisant les dynamiques de neuromédiateurs et leurs rétroactions sur l'activité neuronale. La caractérisation théorique de l'impact de ces rétroactions sur l'excitabilité a été obtenue en formalisant l'étude des variations d'une valeur de bifurcation en un problème d'optimisation sous contrainte. Nous avons enfin proposé un modèle de réseau, pour lequel la dynamique des noeuds est fondée sur le modèle local, incorporant deux couplages: neuronal et astrocytaire. Nous avons observé la propagation d'informations différentiellement selon ces deux couplages et leurs influences cumulées, révélé les différences qualitatives des profils d'activité neuronale et gliale de chaque noeud, et interprété les transitions entre comportements au cours du temps grâce aux structures dynamiques identifiées dans les modèles locaux. / A current issue in neuroscience is to elaborate computational models that are able to reproduce experimental data recorded with various imaging methods, and allowing us to study the relationship between structure and function in the human brain. The modeling objectives of this work are two scales and the model analysis need the development of specific theoretical and numerical tools. At the local scale, we propose a new ordinary differential equations model generating neuronal activities. We characterize and classify the behaviors the model can generate, we compare the model outputs to experimental data and we identify the dynamical structures of the neural compartment underlying the generation of pathological patterns. We then extend this approach to a new neuro-glial mass model: a bilateral coupling between the neural compartment and a new one modeling the impact of astrocytes on neurotransmitter concentrations and the feedback of these concentrations on neural activity is developed. We obtain a theoretical characterization of these feedbacks impact on neuronal excitability by formalizing the variation of a bifurcation value as a problem of optimization under constraint. Finally, we propose a network model, which node dynamics are based on the local neuro-glial mass model, embedding a neuronal coupling and a glial one. We numerically observe the differential propagations of information according to each of these coupling types and their cumulated impact, we highlight qualitatively distinct patterns of neural and glial activities of each node, and link the transitions between behaviors with the dynamical structures identified in the local models.

No description available.

Trophic factors have shown great promise in their potential to treat neurological disease. In particular, glial cell line-derived neurotrophic factor (GDNF) has been identified as a potent neurotrophic factor for midbrain dopamine (DA) neurons in the substantia nigra (SN), which lose function in Parkinson’s disease (PD). GDNF progressed to phase II clinical trials, which did not meet proposed endpoints. The large size and binding characteristics of GDNF have been suspected to contribute to some of the shortcomings of GDNF related to delivery to target brain regions. Smaller peptides derived from GDNF (Dopamine-Neuron Stimulating Peptides – DNSPs) have been recently investigated and appear to demonstrate trophic-like effects comparable to GDNF. In the described studies, a time course study was conducted to determine in vivo DA-release characteristics 1-, 2- and 4- weeks after peptide treatment. These studies determined the effects on DA terminals within striatal sub-regions using microelectrodes. A heterogeneous effect on striatal sub-regions was apparent with the maximum effect in the dorsal striatum – corresponding to terminals originating from the SN. Dysregulation of GDNF or GDNF signaling is believed to contribute to motor dysfunction in aging and PD. Thus, it is hypothesized that GDNF is necessary for the maintenance and function of neurons. To extend this line of investigation, in vivo functional measures (DA-release and -uptake) and behavioral and cellular alterations were investigated in a transgenic mouse model (Gdnf+/-) with reduced GDNF protein levels. The described studies determined that both DA-uptake and -release properties were altered in middle-aged Gdnf+/- mice with only modest reductions in DA neurochemical levels. GDNF levels in Gdnf+/- mice were restored to levels comparable to wild-type (WT) counterparts by treatment with GDNF. GDNF protein supplementation led to enhanced motor behavior and increased markers for DA neurons in the SN of Gdnf+/- mice. Gdnf+/- mice appeared to show a heightened sensitivity to GDNF treatment compared to WT counterparts. Overall, this body of work examines novel synthetic peptides with potential to enhance DA-neuron function and expands upon the current understanding of GDNF’s role in the nigrostriatal pathway.

Background Multiple sclerosis (MS) is an autoimmune disease characterised by inflammatory damage to the central nervous system (CNS). Accumulated CNS injury can be quantified as brain atrophy, definable as a reduction in brain parenchymal fraction (BPF). BPF correlate with disability in MS and is used routinely as an endpoint in clinical trials. In 2009/2010, a new MS clinical care program, that includes follow-up of BPF, was introduced at Umeå University Hospital (NUS). Levels of neurofilament light polypetide (NFL) and glial fibrillary acidic protein (GFAP) in cerebrospinal fluid (CSF) are markers of axonal and astrocytic injury, respectively, and also potential surrogate biomarkers for BPF decline. The goals of this thesis were to establish age-adjusted values of BPF in healthy individuals and to relate these to the BPF values from individuals with MS as well as to the levels of NFL and GFAP in CSF. Another goal was to investigate if expanded disability status scale (EDSS)-worsening could be predicted in a clinical MS cohort and if BPF measurements could contribute to such predictions. Methods A group of 111 healthy individuals volunteered to participate in the studies. A total of 106 of these underwent MRI with BPF measurements, 53 underwent lumbar puncture (LP) with measurement of NFL and GFAP and 48 underwent both MRI and LP. Three different automatic and one manual method were utilised to determine BPF. A literature search on BPF in healthy individuals was performed for the purpose of a systematic review. For studying disability progression in MS, all individuals with MS followed at NUS and included in the Swedish MS registry were included if they had matched data on BPF, EDSS and lesion load as part of clinical follow-up (n=278). Results BPF as well as NFL and GFAP levels in CSF were all associated with age. NFL was associated with BPF and GFAP, but only the association with GFAP was retained when adjusting for age. Significant differences were found between different methods for BPF determination. In the MS population, BPF was associated with EDSS. Only progressive disease course could predict EDSS worsening. Conclusion The data on BPF and levels of NFL and GFAP in CSF of healthy individuals can aid in the interpretation of these variables in the setting of MS. Knowledge on differences in BPF data from different methods for BPF determination can be useful in comparing data across studies, but also highlights the need for a commonly accepted gold standard. The correlation between GFAP and NFL levels in CSF may indicate an association between glial and axonal turnover that is independent of the aging effect on the brain. However, the low number of volunteers for LP precluded clear conclusions. An association between BPF and EDSS was seen in the MS group. The ability to predict EDSS worsening in the clinical MS cohort was limited.

Traumatic brain injury (TBI) affects 3 out of every 1000 Americans each year, and is the leading cause of morbidity and mortality after trauma, accounting for as many as 56,000 deaths per year (Dutton and McCunn, 2003). The Centers for Disease and Control and Prevention found that TBI most commonly occurs in adolescents and young adults aged from 15 to 24 years and in the elderly (75 years and older). Following injury, the secondary injury begins almost immediately after the primary injury and is the result of a number of cascades where once activated, exacerbate the already altered homeostasis of the injured brain. Brain trauma leads to complex secondary injury responses that trigger many cellular and molecular pathways, especially inflammation. The cerebral inflammation that occurs after TBI has been described through the processes of glial activation followed by leukocyte recruitment, and upreglation and secretion of cytokines and chemokines. With aging there is a decrease in the production of anti-inflammatory cytokines along with increasing amounts of pro-inflammatory cytokines by peripheral blood monoculear cells, microglia, and astrocytes. Studies have shown that inflammation has a strong negative effect on neurogenesis in the adult brain due to the impact of the pro-inflammatory cytokines that are released following the acute injury or disease. In this study, we first examined the differences in glial cells responses in young adult brain and aged brain following a moderate lateral fluid percussion injury and the correlation of glial cell activation with hippocampal neurogenesis. We then examined the effect of anti-inflammation treatment on glial cell response in the young and aged brain. The levels of astrocytic and microglial responses in the DG of the hippocampus following injury at 3, 7 or 28 days post-injury were measured using densitometry image analysis on GFAP or Iba1 immunofluorescent labeled brain tissue sections. We found that injury increased both astrocyte and microglial activation and proliferation in both young and aged brain. The young injured animals exhibited greater levels of GFAP while the aged injured animals exhibited greater levels of Iba1 expression at all three time points. We also found that short time anti-inflammatory treatment with minocycline decreased levels of Iba1 expression while increased levels of GFAP expression in both young and aged brain following injury. Our data suggests that there are differences in glial response in the injured young and aged brain that may contribute to the differences in the regenerative and recovery potential in the two age groups following injury.

La conception classique de l'organisation des réseaux cérébraux participant au langage décrit deux zones corticales, l'une frontale (Broca), l'autre temporale intervenant respectivement dans la production et la compréhension du langage, unies par un faisceau de substance blanche: le faisceau longitudinal supérieur. L'imagerie par résonance magnétique d'activation (IRMf) a rendu possible la visualisation de zones d'activation corticales, et l'imagerie en tenseur de diffusion avec la tractographie celle des faisceaux de substance blanche. Ces données nouvelles permettent de repenser l'organisation corticale et sous-corticale du langage. L'ensemble des travaux en imagerie d'activation étaye l'hypothèse d'une dissociation dorso-ventrale du traitement du langage. Les zones de traitement de l'information phonétique étant dorsales, et les centres impliqués dans le traitement sémantique plus ventraux. Imagerie d'activation, imagerie du tenseur de diffusion, stimulations corticales et sous-corticales ont permis d'aboutir à un modèle de réseau du langage impliquant une voie dorsale, essentiellement phonologique et une voie ventrale, sémantique présentant deux composantes. La première est directe, par le faisceau fronto-occipital inférieur connectant les aires temporales postérieures à la région orbito-frontale. La seconde est une voie indirecte qui connecte successivement la région occipito-temporale au pôle temporal par l'intermédiaire du faisceau longitudinal inférieur puis le pôle temporal aux aires basifrontales par le faisceau unciné. Cette dernière voie est compensée après résection ou lors des stimulations per-opératoires, suggérant la possibilité de réseaux de suppléance parallèles et bilatéraux. Dans cette vision d'une voie ventrale sémantique bilatérale, notre travail a pour objet par l'utilisation de l'imagerie fonctionnelle d'activation, d'une part, et de l'imagerie en tenseur de diffusion d'autre part, 1) de vérifier le nombre de faisceaux qui sous-tendent cette voie et en particulier de la part attribuable au faisceau longitudinal moyen; 2) de caractériser les réorganisations de la connectivité fonctionnelle du réseau du langage après une chirurgie de tumeur gliale hémisphérique gauche. Dans la première partie de ce travail, après avoir rappelé la filiation phylogénétique de l'homme et du primate non-humain, en insistant sur les dissemblances qui existent dans leur anatomie corticale et sous-corticale, nous exposons comment ces données ont permis d'aboutir à la découverte du faisceau longitudinal moyen chez l'homme. Nous confirmons la visibilité en imagerie du tenseur de diffusion de ce faisceau et nous précisons ses rapports avec les différents faisceaux de substance blanche constitutifs des voies ventrales et dorsales du langage. Enfin nous discutons ces données tractographiques à la lumière de la dissection et discutons du rôle présumé du faisceau dans le langage. Dans un deuxième temps, nous présentons les concepts de connectivité anatomique, fonctionnelle et effective. Puis nous appliquons un outil d'analyse de la connectivité fonctionnelle à des données périopératoires en tâches de fluence afin de réaliser une cartographie de la plasticité périopératoire de la composante sémantique du langage. Les résultats de cette deuxième étude suggèrent un recrutement de l'hémisphère ipsilatéral à la lésion au décours de la chirurgie. Enfin, nous évoquons la possibilité d'induire une désynchronisation (i.e. une altération de la connectivité) du réseau du mode par défaut par une stimulation peropératoire de la partie postérieure du faisceau cingulaire, induisant une sensation de dépersonnalisation, ces résultats suggérant qu'une des fonctions du noeud le plus postérieur du réseau soit de maintenir un état de conscience du monde extérieur. / According to classical conception of the anatomo-functional organization of language, there are two main cortical areas: a frontal area (Broca) and a temporal one (Wernicke) respectively involved in language production and comprehension. Functional magnetic resonance Imaging (fMRI) reveals cortical areas of activation and diffusion tensor imaging-based tractography (DTI) makes feasible the visualization of white-matter tracts in the human brain. On the basis of these techniques, a new conception of language cortical and sub-cortical organization arose, supporting the hypothesis that language processing network is dissociated in an dorso-ventral way. Dorsal areas of the brain being devoted to phonologic processing and its ventral areas to semantic processing of speech. Different techniques such as fMRI, DTI, intraoperative cortical and subcortical mapping made possible to describe two pathways involved in the language network: a dorsal stream and a ventral stream respectively involved in phonologic and semantic processing. As the dorsal route is composed of a unique pathway, the superior longitudinal fasciculus, the ventral stream appears to be composed of two different pathways. First a direct pathway, the inferior occipitofrontal fasciculus, connecting the posterior temporal areas to the orbitofrontal region. The second one, an indirect pathway, the inferior longitudinal fasciculus links the posterior occipitotemporal to the temporal pole, then relayed by the uncinate fasciculus connecting the temporal pole to the basifrontal areas. According to these observations the aim of our work is In the present work, we aim (1) to confirm that the MdLF is constantly found in control subjects and that it can be delineated from the other fiber tracts that constitute language pathways, (2) to characterize the reorganization of language network's functional connectivity follmowing surgical removal of left hemisphere low grade gliomas. In this study, we confirmed that the MdLF is constantly found in healthy volunteers and we clearly delineate the MdLF from the other fascicles that constitute language pathways, especially the ventral pathway. Considering language plasticity, our findings suggest that in the postoperative period, brain plasticity occurs with an ipsilateral recrutment and increased fonctional connectivity in the left hemisphere. Finally, we report a collaborative work observing that intraoperative electrostimulations of the white matter underlying the left posterior cingulate, while performing a naming task, systematically induced an unresponsive state for few seconds in relationship with a dream-like state. This result provides direct evidence that connectivity underlying the posterior node of the default mode network permits maintained consciousness of the external world.

A organização do sistema nervoso que controla as funções digestórias dos moluscos gastrópodes tem sido estudada quanto à constituição dos circuitos neurais subjacentes ao ritmo de deglutição alimentar. Existe, entretanto, uma lacuna no conhecimento da organização do sistema nervoso central (SNC) e periférico (SNP) que regulam o segmento médio e posterior do trato digestório. A posição filogenética intermediária, atribuída ao sistema nervoso (SN) do caracol Megalobulimus abbreviatus, entre as espécies de Helicidae e os basomatófaros pode constituir uma via para o entendimento do controle da atividade do trato gastrointestinal (tGI) de gastrópodes. Assim sendo, o caracol pulmonado M. abbreviatus foi utilizado em um estudo morfológico e neuroquímico que buscou descrever o padrão da inervação central e periférica em um modelo experimental amplamente utilizado na pesquisa neurobiológica. A anatomia macroscópica revelou que o intestino médio constituiu-se pelo estômago, dividido em pró-ventrículo e moela, e intestino, dividido em pró-intestino ou tiflossolear, médio e pós-intestino, enquanto que o intestino posterior constituiu-se pelo reto e ânus. A análise da organização da parede, empregando microscopia óptica, revelou a presença de quatro túnicas constituindo a parede destes órgãos: (i) mucosa, que se constituía por um epitélio colunar intermitente ciliado e lâmina própria; (ii) submucosa, representada pelo tecido conjuntivo frouxo, contendo muitos espaços hemais; (iii) muscular, dividida em camadas circular interna e longitudinal externa, contudo a moela apresentou uma camada disposta obliquamente e as regiões cárdica e pilórica apresentaram esfíncteres muito organizados (iv) serosa, constituída por tecido conjuntivo frouxo delimitado por um mesotélio. O intestino médio recebe inervação central por meio do ramo gastro-intestinal (rG) do nervo visceral comum (nV), enquanto que o intestino posterior foi inervado pelo nervo reto-anal (nR). A aplicação de marcações retrógradas com cloreto de cobalto acrescido de albumina sérica bovina, biocitina e Horseradish peroxidase no rG e no nR revelou que a maioria dos neurônios envolvidos no controle destes órgãos estão localizados no complexo ganglionar víscero-parietal. Ainda foi observada a presença de uma rede constituída por quatro gânglios (estomatogástrico, cárdico, gástrico e pilórico) interconectados por nervos e localizados sobre a parede do estômago, sendo denominado sistema nervoso estomatogástrico (SNEG). O traçamento anterógrado com Lúcifer Yellow revelou que fibras oriundas do SNEG se projetam para os plexos entéricos, submucoso (PS) e mioentérico (PM), localizados entre as túnicas do tGI. A organização do sistema nervoso entérico (SNE) foi estudada com a aplicação das técnicas de impregnação argentafínica e coloração com azul de metileno. Os plexos entéricos mostraram-se formados por uma extensa rede de axônios e muitos somas neuronais, dispostos em pequenos grupos ou isoladamente. As fibras axonais que inervavam as células da camada muscular longitudinal no estômago eram organizadas em feixes e acompanhavam o comprimento das fibras musculares. O MP distribuía-se por toda a camada muscular circular e longitudinal. No estômago, a região cárdica apresentou um plexo mais denso do que a pilórica, contudo as fibras nervosas dispunham-se entre e ao redor das fibras musculares de ambas as camadas O plexo entérico no intestino apresentou o mesmo arranjo observado na região pilórica, sendo uniforme até o ânus. As duas tiflossoles intestinais, no pró-intestino, apresentaram grande quantidade de fibras nervosas, no entanto não foram observados somas neuronais. Dentre os constituintes do SNE foram observados células nervosas intra-epiteliais (neuron like-intraepithelial cells), que possuem dois tipos morfológicos: aberto (que projeta um cílio para o lúmen intestinal) e fechado (localizado na base do epitélio digestório) e células fusiformes, cuja morfologia e posição lembram as células intersticiais de Cajal. A neuroanatomia química do SNEG e do SNE foi analisada mediante a aplicação de técnicas de histoquímica e imunohistoquímica para diferentes mediadores e transmissores. No intestino médio e posterior foi observado um rico plexo com atividade acetilcolinesterásica (AChE), constituído por fibras oriundas do SNC, via nervos periféricos, e do SNEG. Neurônios e fibras nervosas entéricas mostraram-se esparsos na submucosa e entre as camadas musculares, circular e longitudinal, do estômago, intestino e reto. A atividade de diaforase da nicotinamida adenina dinucleotódeo fosfato (NADPHd) revelou neurônios e fibras nervosas com maior atividade em toda a túnica muscular do que na submucosa. A fluorescência induzida pelo ácido glioxílico (AG) revelou a maior presença de fibras nervosas e varicosidades catecolaminérgicas na submucosa do reto, pós-intestino e moela do que nas outras porções do tGI. A imunorreatividade à serotonina (5HT-ir) foi observada em somas e fibras nervosas distribuídas predominantemente na submucosa do reto e intestino, sendo encontrados poucos neurônios e fibras 5HT-ir no pró-ventrículo e moela Os elementos nervosos FMRF-amida imunorreativos (FMRFa-ir) estavam presentes na mucosa, submucosa e muscular por toda extensão do intestino médio e posterior. As células nervosas intraepiteliais foram mais marcadas pela AChE, 5HT-ir e FMRFa-ir do que pela NADPHd e seus processos se anastomosam formando um extenso e organizado plexo subepitelial. As células fusiformes tiveram os corpos e prolongamentos marcados pelos métodos aplicados, à exceção do AG. Uma intensa imunorreatividade a proteína fibrilar acídica glial (GFAP-ir) por todos os plexos do intestino médio e posterior e nos gânglios do SNEG, sugerindo uma importante função para as células gliais no SNP do tGI de gastrópodes. Assim, pode-se concluir que o controle do tGI no caracol M. abbreviatus possui um controle nervoso extrínseco direto, por meio dos gânglios subesofageais, via rG e nR, e indireto, pelo SNEG para o intestino médio, e uma inervação intrínseca, representada pelos plexos PS e PM, associados às células nervosas intra-epiteliais, que formam o plexo subepitelial tanto no intestino médio como no posterior. A neuroanatomia química permite inferir que, os diferentes transmissores analisados, podem exercer controle sobre a motilidade ou sobre as funções sensoriais e secretomotoras no tGI. Finalizando, a reação ao GFAP é uma evidência da presença de células enterogliais permitindo inferir que exista uma interação entre os constituintes dos plexos neurais com a glia, tal qual ocorre no SNC de gastrópodes e outros invertebrados. / The organization of the nervous system that controls digestive functions of gastropods mollusks has been studied relative to the constitution of the neuronal circuit underlying the deglutition rhythm. However, there is a lacuna in the knowledge about the organization of the peripheral nervous system regulating the medium and posterior segments of the digestive tract. However, there is a lacuna in the knowledge about the organization of the central (CNS) and peripheral nervous system (PNS) that regulates the medium and posterior segments of the digestive tract. The intermediate phylogenetic position attributed to the nervous system (NS) of the snail Megalobulimus abbreviatus, between Helicidae and basommatophoran species may constitute a via for understanding the control of the activity of the gastrointestinal (GI) tract of gastropods. Thus, the pulmonate snail M. abbreviatus was used in a morphological and neurochemical study that sought to describe the pattern of the central and peripheral innervation in an experimental model widely used in neurobiological research. Macroscopic anatomy revealed that the midgut was formed by the stomach, divided into pro-ventricle and gizzard, and intestine, divided into pro-intestine or tiflossolear, medium- and post-intestine, while the hindgut was formed by the rectum and anus. The light microscopy revealed that the GIt wall was constituted by four tunics: (i) the mucosa was constituted by a intermittent ciliated columnar epithelium and lamina propria; (ii) the submucosa was a loose connective tissue, containing a system of haemocoelic spaces; (iii) the muscular was formed by the internal circular and external longitudinal layers, while in the gizzard there was a third muscular layer disposed obliquely and the cardia and pylorus regions contained two sphincters (iv) the serosa display a loose connective tissue covered by a mesothelium. The midgut is innervated by the common visceral nerve, through gastrointestinal branch (Gb), while the hindgut is innervated by the rectum-anal nerve (Rn). Retrogradely backfilling with CoCl2 added with 0.1% bovine albumin, byocitin and horseradish peroxidase from the Gb and Rn is employed to reveal the neurons innervating these digestive regions which are located in all ganglia within the viscera-parietal ganglia complex. Although we observed the presence of a network of four ganglia: stomatogastric, gastric, cardic and pyloric, interconnected by nerves and located outer the surface of the stomach, which in the present study was referred to as the stomatogastric nervous system (STNS). Anterogradely labelin with Lucifer yellow which fibers of the STNS project to the submucous (SP) and myenteric plexuses (MP). The morphology of the enteric nervous system (ENS) was described using silver diammine impregnation and methylene blue staining. These plexuses were formed by extensive axonal networks and by several neuronal somata which are arranged in small clusters or as isolated cells. The axonal fibers innervating the longitudinal muscle cells in the stomach wall are organized in small bundles along the muscle length. The MP is distributed throughout the circular and longitudinal muscular layer. In the stomach, the cardic area plexus is denser than the pyloric plexus, while the nervous fibers of both are located between and around the muscular bundles The enteric plexus in the intestine is a continuity of the pyloric arrangement, staying uniform until the anus. In both typhlosoles of the pro-intestine nerve bundles are found in large numbers but none neuron is observed. In addition to the plexus were observed were observed neuron-like intraepithelial cells, which possess two types: open (a cilium projecting into the intestinal lumen) and closed (located at the base of the digestive epithelium) and fusiform cells whose morphology and position resembling interstitial cells of Cajal. The chemical neuroanatomy of the STNS and SNE was analyzed by histochemistry and immunohistochemistry methodos for different mediators and transmitters. In the midgut and hindgut, the plexus have a very intense AChE activity and it was constituted by fibers originated from the STNS or from the subesophageal complex through peripheral nerves. The enteric neurons and fibers with AChE activity were scattered in the submucosa and between the circular and longitudinal muscle layers of the stomach, intestine and rectum. Neuronal bodies and fibers with NADPHd activity are more abundant in the entire mass of smooth muscle elements than the submucosal layer. Fluorescent induced by GA revealed the presence of catecholaminergic nerve fibers and varicosities in the submucosal layer of the rectum, gizzard and post-intestine than in others organs of the GIt. The immunoreactivity to serotonin (5HTir) elements was predominantly distributed in the submucosal layer of the intestine and rectum. Few 5HTir fibers was verify in the proventricle and gizzard The FMRFa-immunoreactive elements were present in the mucosal, submucosal and muscular layers throughout the mid and hindgut. The neuron-like intraepithelial cells were more labeled by AChE, 5HT and FMRFa than for NADPHd and their processes were organized forming a subepithelial plexus. The bodies and processes of the fusiform cells were labeled by the methods applied extensions, except for the GA. It was found an intense glial fibrilary acidic protein immunorreaction (GFAP-ir) were visualized, throughout the midgut and hindgut plexuses and in the ganglia of the STNS. This intense immunoreaction to GFAP in intramural plexuses suggests important roles to glial cells in the peripheral nervous system of digestive tract of this pulmonate snail. Therefore, the gastrointestinal tract is controlled directly by extrinsic innervation from the subesophageal ganglia or indirectly via STNS (for the midgut) and by an intrinsic innervation, represented by the MP and SP for both mid and hindgut. The data obtained from the neurochemical approaches utilized in the GIt we infer that these different transmitter systems could exert putative roles in the motility or the secretomotor or sensorial functions of GIt. Finally, as an evidence of the enteric glial cells, the neural constituents of the snail GIt wall have a interaction with glia similar to have been described to invertebrate CNS represent a new approach to study of the ENS in gastropod and other invertebrates.

A cafeína é o psicoestimulante mais consumido em todo o mundo, cujos efeitos benéficos nas funções cognitivas têm sido observados em diferentes condições e modelos animais. O consumo de cafeína é difundido entre adultos, idosos, gestantes e mais recentemente, entre crianças e adolescentes. Alguns estudos clínicos e pré-clínicos sugerem que a exposição pré-natal à cafeína apresenta efeitos prejudiciais, como prematuridade, malformações congênitas, baixo peso ao nascer e mesmo teratogenicidade, enquanto outros estudos não demonstraram efeitos deletérios a longo prazo da cafeína. Além disso, poucos estudos têm abordado os efeitos da cafeína nas diferenças de sexo durante a puberdade e/ou adolescência. Devido ao alto consumo de bebidas contendo cafeína por crianças e adolescentes, existe uma grande preocupação a respeito dos seus potenciais efeitos nocivos nessas subpopulações. Assim, considerando que o consumo de cafeína tem crescido nesta população, no primeiro capítulo desta tese investigamos as alterações comportamentais e de proteínas sinápticas em ratos machos e fêmeas púberes expostos à cafeína pelo consumo materno durante a gestação, lactação e na água de beber até o início da puberdade. Ratas Wistar adultas receberam cafeína na água de beber (0.1 e 0.3 g/L) durante o seu ciclo ativo, em dias úteis, duas semanas antes do acasalamento até o desmame, quando então os filhotes passaram a consumir a cafeína até o início da sua puberdade (30-34 dias de idade) A análise comportamental e os níveis de proteínas sinápticas (pró-BDNF, BDNF, GFAP e SNAP-25) foram analisados no hipocampo e córtex cerebral. As fêmeas púberes apresentaram uma atividade locomotora maior e comportamento menos ansioso que os machos. Em ambos os sexos, a cafeína causou hiperlocomoção no campo aberto. Enquanto a cafeína em doses moderadas causou um prejuízo na memória de reconhecimento em fêmeas, foi observado uma melhora na memória de longo prazo em ambas as doses em ratos machos. O comportamento relacionado à ansiedade foi atenuado pela cafeína (0,3 g/L) apenas em fêmeas. Paralelamente com a melhora da memória nos machos, a cafeína aumentou os níveis de pró-BDNF e BDNF no hipocampo e córtex. As fêmeas apresentaram um aumento do pró-BDNF em ambas as regiões avaliadas em comparação aos machos. Embora a proteina GFAP não tenha sido alterada pelas diferenças de sexo e pelo tratamento com cafeína, a cafeína em doses moderadas aumentou o imunoconteúdo de SNAP-25 no córtex das fêmeas. Os resultados demonstram que o consumo de cafeína altera de forma distinta a memória de reconhecimento e o comortamento do tipo ansioso em ratos machos e fêmeas púberes. Além disso, o BDNF e proteínas relacionadas também foram modificados de uma forma dependente do sexo, sugerindo que alterações sinápticas ou de plasticidade podem estar associadas aos efeitos comportamentais Além dos efeitos da cafeína durante a gravidez e a puberdade, têm sido observados efeitos benéficos da cafeína sobre a memória no envelhecimento normal e no prejuízo observado em em modelos animais de doenças neurodegenerativas. Tendo em vista que os mecanismos subjacentes a estes efeitos da cafeína ainda permanecem desconhecidos, no segundo capítulo investigamos se a administração crônica de cafeína poderia melhorar o desempenho na tarefa de memória avaliada pelo teste da esquiva inibitória em ratos adultos e de meia-idade. Como o BDNF está associado com a formação da memória e as ações do BDNF são moduladas pelos receptores de adenosina, os alvos moleculares para as ações psicoestimulantes da cafeína, neste estudo avaliamos os efeitos da administração crônica de cafeína (1 g/L na água de beber durante 30 dias) na memória de curta e longa duração e nos níveis de pró- BDNF, BDNF maduro,o receptor TrkB e o fator de transcrição CREB no hipocampo de ratos machos adultos (3 meses de idade) e de meia-idade (12 meses) Ambos os gruposforam submetidos a tarefa de campo aberto e esquiva inibitória. Os ratos de meia-idade apresentaram diminuição da atividade locomotora em relação aos adultos e a cafeína não teve efeitos sobre a locomoção em ambas idades Na tarefa de esquiva inibitória, avaliou-se a memória de curta e longa duração. Ratos de meia-idade apresentaram um comprometimento total da memória de curta duração, e parcial da memória de longa duração em comparação com ratos adultos. O consumo de cafeína foi capaz de reverter o prejuízo decorrente da idade tanto para a memória de curta quanto de longa duração. O aumento do BDNF hippocampal causado pelo envelhecimento foi prevenido pelo consumo de cafeína, juntamente com um aumento no imunoconteúdo de pró-BDNF e CREB em ambas as idades. Além disso, os níveis de CREB aumentaram com o envelhecimento. Houve uma diminuição no imunoconteúdo de TrkB no hipocampo de ratos de meia-idade quando comparados aos adultos, e a cafeína diminuiu a densidade de TrkB em ambas as idades. Os dados encontrados indicam uma estreita associação entre a modificação do desempenho da memória e imunoconteúdo BDNF. Em conjunto, esses resultados apresentam novos indícios de que o consumo de cafeína promove desfechos comportamentais sexo-específicos em ratos púberes, além de ser capaz de normalizar o desempenho em tarefas de memória e alterações na sinalização do BDNF causadas pelo envelhecimento. / Caffeine is the most consumed psychostimulant worldwide, and the beneficial effects of chronic caffeine administration on cognitive function have been observed in different conditions and animal models. Caffeine consumption is widespread among adults, eldery, pregnant women and more recently, children and adolescents. Some clinical and preclinical studies suggest that prenatal exposure to caffeine presents harmful effects, such as prematurity, congenital malformations, low birth weight and even teratogenicity, whereas others studies demonstrated no long-term harmfull effects of caffeine. Besides that, few studies have addressed the effects of caffeine in a sex dependent manner during puberty and/or adolescence. Also, due to the increase in the consumption of caffeine containing drinks by children and adolescents, the potential harmful effects of caffeine in these subpopulations need to be investigated. Considering that caffeine intake has grown in this population, in the first chapter of the this thesis we investigated the behavioral and synaptic proteins changes in pubescent male and female rats after maternal consumption of caffeine. Adult female Wistar rats started to receive caffeine in drinking water (0.1 and 0.3 g/L; low and moderate dose, respectively) during the active cycle in weekdays, two weeks before mating. The treatment lasted up to weaning (21 days) and offspring continued receiving caffeine until the onset of puberty (30-34 days old). Behavioral analysis and synaptic proteins levels (proBDNF, BDNF, GFAP and SNAP-25) were immunodetected in the hippocampus and cerebral cortex. Pubescent females showed hyperlocomotion and less anxiety behavior as compared to males. In both sexes caffeine caused hyperlocomotion in the open field. While moderate caffeine worsened recognition memory in females, an improvement for long-term memory in both doses was observed in male rats Anxiety-related behavior was attenuated by caffeine (0.3 g/L) only in females. Also, in parallel with memory improvement in males, caffeine increased pro- and BDNF in the hippocampus and cortex. Females presented increased proBDNF in both brain regions as compared to males. While GFAP was not different according to sex or altered by caffeine consumption, moderate caffeine increased SNAP-25 in the cortex of female rats. Our findings revealed that caffeine differently affects recognition memory and anxietyrelated behaviors in pubescent male and female rats. In addition, BDNF and related proteins have also changed in a sex dependent manner, suggesting an association with behavioral outcomes. Beyond caffeine effects during pregnancy and puberty, beneficial effects of caffeine on memory processes have been observed in animal models relevant to neurodegenerative diseases and aging, although the underlying mechanisms remain unknown. In the second chapter we investigated whether chronic caffeine consumption could improve the performance in inhibitory avoidance memory task in adult and middle-aged rats. Because brain-derived neurotrophic factor (BDNF) is associated with memory formation and BDNF’s actions are modulated by adenosine receptors, the molecular targets for the psychostimulant actions of caffeine, we here compare the effects of chronic caffeine (1 mg/mL drinking solution for 30 days) on short- and long term memory and on levels of hippocampal proBDNF, mature BDNF, TrkB and CREB in young (3 month old) and middle-aged (12 month old) male rats. Both groups were submitted to open field and inhibitory avoidance tasks. Middle-aged rats presented decreased locomotor activity as compared to adults and caffeine was devoid of effect at any age. In the inhibitory avoidance task, short- and long-term memory was evaluated Middle-aged rats presented impaired performance compared to adult ones for short-term memory. When long-term memory was evaluated, middle-aged rats showed a decreased in their perfomances compared to adult rats, and caffeine treatment was able to improveit. Western blot analysis showed that BDNF and CREB imunocontent increased in the hippocampus of aged rats and caffeine consumption was able to prevent the changes in BDNF levels. In addition, caffeine treatment increased the pro-BDNF and CREB immunocontent in both ages. Furthermore, CREB densities increased with aging. TrkB immunocontent was decreased in the hippocampus from middle-aged rats when compared to adult ones, and caffeine decreased the density of TrkB in both ages. The present findings indicate a close association between the modification of memory performance and BDNF immunocontent. Therefore, our data suggest caffeine normalyze memory performance upon aging and may be related to the ability of caffeine to normalyze the levels of BDNF. Taken together, these results present new evidence that caffeine consumption promotes sex-specific behavioral outcomes in addition to being able to normalize memory performance during aging and that changes could be related to a modification in BDNF signaling.

O núcleo medial (Me) é parte superficial do complexo amigdaliano e ainda muito pouco se conhece de seus constituintes celulares em seres humanos. Neste estudo desenvolveu-se uma adaptação do método de Golgi do tipo “single-section” para tecido nervoso humano fixado e conservado em formalina por tempo variável. Além disso, descreveu-se a densidade de neurônios e células da glia no Me, sua morfologia geral, incluindo detalhes de espinhos dendríticos e terminações axonais, a imunorreatividade à proteína ácida fibrilar glial (GFAP) e a ultraestrutura sináptica local. Como resultados demonstrou-se que as células da glia são maioria neste núcleo (cerca de 72% do total de células) e que há significativamente mais neurônios no Me do hemisfério esquerdo (1.53 X 105 neurônios/mm3). Os somas neuronais impregnados pelo método de Golgi demonstraram-se redondos/ovais, fusiformes ou poligonais (diâmetros entre 10-30 μm), os dendritos estenderam-se por distâncias variadas e contiveram espinhos pleomórficos, caracterizando neurônios com menos e mais espinhos dendríticos (densidades de 1,5 até 5,2 espinhos/μm), e os axônios revelaram terminações desde simples até muito complexas. Os neurônios multipolares foram classificados em Tipos 1, 2 ou 3 de acordo com trabalhos prévios, ou ainda em tipos morfológicos ainda não classificados Observaram-se astrócitos protoplasmáticos com muitos prolongamentos reativos à GFAP, isolados ou em grupos. Esses, no estudo ultra-estrutural, compuseram sinapses “tripartites” e “tetrapartites”, considerando-se o quarto elemento o da matriz extracelular situada entre os elementos pré- e pós-sinápticos. As sinapses axodendríticas apresentaram-se tanto assimétricas (com vesículas redondas pequenas e elétron-lúcidas) como simétricas (com vesículas pleomórficas pequenas e claras e, adicionalmente, com vesículas redondas grandes ou pequenas de centro escuro). Terminais axonais estabelecendo múltiplas sinapses assimétricas, classificados como de tipo “glomérulo”, também foram observados. A presente tese contribui com dados descritivos e quantitativos inéditos sobre a morfologia das células do Me, o que pode servir de base para o entendimento e novas investigações sobre o funcionamento desse núcleo em situações normais ou patológicas em seres humanos. / The medial nucleus (Me) is a superficial component of the amygdaloid complex. Little is currently known about its cellular composition in humans. Here is reported an adaptation of the “single-section” Golgi method for formalin fixed and stored human brain for diversified periods. Furthermore, the density of neurons and glial cells in the Me, their general morphology including dendritic spines and axonal terminals details, the glial fibrillary acidic protein (GFAP) immunoreactivity, and features of local cells under electron microscopy are described. Our results show that Me had an estimated mean neuronal density around 1.53 X 105 neurons/mm3 (higher in the left hemisphere), more glia (72% of all cells) than neurons, and a nonneuronal/neuronal ratio of 2.7. Golgi-impregnated neurons had cell bodies with a round/ovoid, fusiform or polygonal shape (diameters ranging from 10 to 30 μm), dendrites with varying lengths and pleomorphic spines that characterized neurons more or less spiny (density varying from1.5 to 5.2 spines/μm), and ranging from simple to very complexes terminal axons. Neurons appeared as “bitufted” or stellate multipolar cells, or classified in “Types 1 to 3” according to previous immunohistochemical observations, or other still unclassified morphologies. Protoplasmic astrocytes, either isolated or forming small clusters, were observed and showed multiple branches immunoreactive for GFAP, being equally distributed between right and left hemispheres They were found composing tripartite synapses or, together with an evident extracellular matrix between pre- and postsynaptic elements, tetrapartite ones. Axo-dendritic synapses were both asymmetrical (with various small, round electron-lucent vesicles) and symmetrical (with small pleomorphic vesicles and, occasionally, few intermingled large dense-core vesicles). Terminal axons with a glomerular-like structure were also found forming various asymmetric contacts. The present thesis add novel descriptive and qualitative information about neuronal and glial population of the human Me, which provide a basic contribution to our understanding, and to further research, of the functional implications of the Me in the brain organization both in normal and pathological conditions .