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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

Mécanismes de neuromodulation impliqués dans les arythmies auriculaires

Jacques, Frédéric January 2007 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
202

Mise en oeuvre d’une plateforme de gestion et de dissémination des connaissances pour des réseaux autonomiques / A knowledge management and dissemination platform for autonomic networks

Souihi, Sami 03 December 2013 (has links)
La croissance du réseau Internet, l'émergence de nouveaux besoins par l'avènement des terminaux dits intelligents (smartphones, tablettes tactiles, etc.) et l'apparition de nouvelles applications sous-jacentes induisent de nombreuses mutations dans l'usage de plus en plus massif des technologies de l'information dans notre vie quotidienne et dans tous les secteurs d'activités. Ces nouveaux usages ont nécessité de repenser le fondement même de l'architecture réseau qui a eu pour conséquence l'émergence de nouveaux concepts basés sur une vue "centrée sur l'usage" en lieu et place d'une vue "centrée sur le réseau". De fait, les mécanismes de contrôle du réseau de transport doivent non seulement exploiter les informations relatives aux plans de données, de contrôle et de gestion, mais aussi les connaissances, acquises ou apprises par inférence déductive ou inductive, sur l'état courant du réseau (trafic, ressources, rendu de l'application, etc.) de manière à accélérer la prise de décision par les éléments de contrôle du réseau. Les travaux faits dans le cadre de cette thèse concernent ce dernier aspect et rejoignent plus généralement ceux tournés sur les réseaux autonomiques. Il s'agit dans cette thèse de mettre en oeuvre des méthodes relatives à la gestion, à la distribution et à l'exploitation des connaissances nécessaires au bon fonctionnement du réseau de transport. Le plan de connaissances mis en oeuvre ici se base à la fois sur l'idée de développer une gestion au sein d'une structure hiérarchisée et adaptative où seuls certains noeuds sélectionnés sont en charge de la dissémination des connaissances et l'idée de relier ces noeuds au travers d'un ensemble de réseaux couvrants spécialisés permettant de faciliter l'exploitation de ces connaissances. Comparée aux plateformes traditionnellement utilisées, celle développée dans le cadre de cette thèse montre clairement l'intérêt des algorithmes élaborés au regard des temps d'accès, de distribution et de partage de charge entre les noeuds de contrôle pour la gestion des connaissances. A des fins de validation, cette plateforme a été utilisée dans deux exemples d'application: le Cloud computing et les smartgrids / The growth of the Internet, the emergence of new needs expressed by the advent of smart devices ( smartphones, touchpads , etc. ) and the development of new underlying applications induce many changes in the use of information technology in our everyday life and in all sectors. This new use that match new needs required to rethink the foundation of the network architecture itself, which has resulted in the emergence of new concepts based on a "use-centeric" view instead of a "network-centric" view. In fact, the control mechanisms of the transmission network must not only exploit the information on data, control and management planes, but also the knowledge acquired or learned by inductive or deductive inference on the current state of the network (traffic, resources, the rendering of the application, etc.) to accelerate decision making by the control elements of the network. This thesis is dealing with this latter aspect, which makes it consistent with work done on autonomic networks. It is about conceiving and implementing methods for the management, distribution and exploitation of knowledge necessary for the proper functioning of the transmission network. The knowledge plane that we implemented is based on both the idea of developing a management within an adaptive hierarchical structure where only some selected nodes are responsible for the dissemination of knowledge and the idea of linking these nodes through a spanning set of specialized networks to facilitate the exploitation of this knowledge. Compared to traditionally used platforms, the one developed in this thesis clearly shows the interest of the developed algorithms in terms of access time, distribution and load sharing between the control nodes for knowledge management. For validation purposes, our platform was tested on two application examples : Cloud computing and smart grids
203

Accidental hypothermia and local cold injury : physiological and epidemiological studies on risk

Brändström, Helge January 2012 (has links)
Background: (Papers I and II) The objectives were to first determine incidence and contributing factors to cold-related injuries in northern Sweden, both those that led to hospitalization and those that led to fatality.  (Papers III and IV) A further aim was to assess post-cooling hand-rewarming responses and effects of training in a cold environment, both on fingertip rewarming and on function of the autonomic nervous system, to evaluate if there was adaptation related to prolonged occupational cold exposure. Methods:  In a retrospective analysis, cases of accidental cold-related injury with hospital admission in northern Sweden during 2000-2007 were analyzed (Paper I).  Cases of fatal hypothermia in the same region during 1992-2008 were analyzed (Paper II).  A cohort of volunteers was studied before and after many months of occupational cold exposure. Subject hand rewarming response was measured after a cold hand immersion provocation and categorized as slow, moderate or normal in rewarming speed.  This cold provocation and rewarming assessment was performed before and after their winter training.  (Paper III).  Heart rate variability (HRV) was analyzed from the same cold provocation/recovery sequences (Paper IV). Results:  (Paper I) For the 379 cases of hospitalization for cold-related injury, annual incidences for hypothermia, frostbite, and drowning were 3.4/100,000, 1.5/100,000, and 1.0/100,000 inhabitants, respectively.  Male gender was more frequent for all categories.  Annual frequencies for hypothermia hospitalizations increased during the study period.  Hypothermia degree and distribution of cases were 20 % mild (between 32 and 35ºC), 40% moderate (31.9 to 28ºC), and 24% severe (< 28ºC), while 12% had temperatures over 35.0ºC.  (Paper II) The 207 cases of fatal hypothermia showed an annual incidence of 1.35 per 100,000 inhabitants, 72% in rural areas, 93% outdoors, 40% found within 100 meters of a building.  Paradoxical undressing was documented in 30%.  Ethanol was detected in femoral vein blood in 43%. Contributing co-morbidity was common including heart disease, previous stroke, dementia, psychiatric disease, alcoholism, and recent trauma.  (Paper III) Post-training, baseline fingertip temperatures and cold recovery variables in terms of final rewarming fingertip temperature and vasodilation time increased significantly in moderate and slow rewarmers.  Cold-related injury (frostbite) during winter training occured disproportionately more often in slow rewarmers (4 of the 5 injuries).  (Paper IV) At ‘pre- winter-training’, normal rewarmers had higher power for low frequency and high frequency heart rate variability.  After cold acclimatization (post-training), normal rewarmers showed lower resting power values for the low frequency and high frequency heart rate variability components.  Conclusions: Hypothermia and cold injury continues to cause injury and hospitalization in the northern region of Sweden.  Assessment and management is not standardized across hospitals.  With the identification of groups at high risk for fatal hypothermia, it should be possible to reduce the incidence, particularly for highest risk subjects; rural, living alone, alcohol-imbibing, and psychiatric diagnosis-carrying citizens.  Long-term cold-weather training may affect hand rewarming patters after a cold provocation, and a warmer baseline hand temperature with faster rewarming after a cold provocation may be associated with less general risk for frostbite.  Heart rate variability results support the conclusion that cold adaptation in the autonomic nervous system occurred in both groups, though the biological significance of this is not yet clear.
204

Survey of Autonomic Computing and Experiments on JMX-based Autonomic Features

Azzam, Adel R 13 May 2016 (has links)
Autonomic Computing (AC) aims at solving the problem of managing the rapidly-growing complexity of Information Technology systems, by creating self-managing systems. In this thesis, we have surveyed the progress of the AC field, and studied the requirements, models and architectures of AC. The commonly recognized AC requirements are four properties - self-configuring, self-healing, self-optimizing, and self-protecting. The recommended software architecture is the MAPE-K model containing four modules, namely - monitor, analyze, plan and execute, as well as the knowledge repository. In the modern software marketplace, Java Management Extensions (JMX) has facilitated one function of the AC requirements - monitoring. Using JMX, we implemented a package that attempts to assist programming for AC features including socket management, logging, and recovery of distributed computation. In the experiments, we have not only realized the powerful Java capabilities that are unknown to many educators, we also illustrated the feasibility of learning AC in senior computer science courses.
205

Maintenance automatique du réseau programmable d'accès optique de très haut débit / Autonomic maintenance of high programmable optical access network

Frigui, Nejm Eddine 21 January 2019 (has links)
Les réseaux optiques passifs (PONs, Passive Optical Networks) représentant l’une des solutions les plus performantes du réseau d’accès FTTH ont été largement déployés par les opérateurs grâce à leur capacité d’offrir des services de très haut débit. Cependant, en raison de la dynamicité du trafic des différents clients, ces réseaux doivent s’appuyer sur un mécanisme efficace pour l’allocation de ressources, plus particulièrement dans le sens montant. Ce mécanisme est actuellement limité par la nature statique des paramètres SLA (Service Level Agreement). Ceci peut avoir une influence négative sur la qualité de service ressentie par les utilisateurs. L’objectif de cette thèse est de proposer une nouvelle architecture pour optimiser l’allocation de ressources dans les réseaux PON tout en agissant uniquement sur les paramètres SLA, désignés comme des paramètres gérables par l’opérateur. Des techniques de classification basées sur l’apprentissage automatique et la prédiction sont utilisées pour analyser le comportement des différents utilisateurs et déterminer leurs tendances de trafic. Un ajustement dynamique sur la base du concept autonomique de certains paramètres SLA est ensuite effectué afin de maximiser la satisfaction globale des clients vis-à-vis du réseau. / Passive Optical Network (PON) representing one of the most attractive FTTH access network solutions, have been widely deployed for several years thanks to their ability to offer high speed services. However, due to the dynamicity of users traffic patterns, PONs need to rely on an efficient upstream bandwidth allocation mechanism. This mechanism is currently limited by the static nature of Service Level Agreement (SLA) parameters which can lead to an unoptimized bandwidth allocation in the network. The objective of this thesis is to propose a new management architecture for optimizing the upstream bandwidth allocation in PON while acting only on manageable parameters to allow the involvement of self-decision elements into the network. To achieve this, classification techniques based on machine learning approaches are used to analyze the behavior of PON users and to specify their upstream data transmission tendency. A dynamic adjustment of some SLA parameters is then performed to maximize the overall customers’ satisfaction with the network.
206

Análise da variabilidade da frequência cardíaca em cães saudáveis em diferentes faixas etárias

Romão, Luciene Maria Martinello January 2019 (has links)
Orientador: Maria Lucia Gomes Lourenço / Resumo: A modulação autonômica da frequência cardíaca reflete-se na variabilidade da frequência cárdiaca (VFC). Estudos em humanos hígidos mostraram que a VFC sofre redução com o avançar da idade e também que há uma imaturidade autonômica em neonatos, alterando esses índices. Esta análise apresenta perspectivas interesantes em cães, contudo, antes mesmo que possa ser utilizada, é pertinente que se estabeleça melhor compreensão sobre o comportamento fisiológico da modulação autonômica cardíaca. O objetivo desse estudo foi descrever um padrão característico de comportamento autonômico cardíaco em cães saudáveis em diferentes faixas etárias. Foi analisada a VFC no domínio do tempo e no domínio da frequência, utilizando o Holter e o frequencímetro em curto prazo em 87 cães. Observou-se que cães entre um e sete anos de idade, apresentaram maior VFC quando comparada a outras faixas etárias. Cães idosos (> 8 anos), exibiram tendência natural a diminuição dos marcadores parassimpáticos cardíacos da VFC, enquanto cães filhotes (< 1 ano), apresentaram maior predomínio simpático e consequentemente, menor VFC. Conclui-se que o balanço dos sistemas simpático e parassimpático, sofre influência da idade em cães, alterando os valores da VFC. Então é de extrema importância obter valores de referência, para futuras análises em diferentes afecções clínicas. Estas análises podem ser realizadas pelo Holter e frequencímetro cardíaco, mesmo apresentando limitações para cães, ambos os métodos avaliam a VFC. / Abstract: Autonomic heart rate modulation is reflected by heart rate variability (HRV). Studies in healthy human subjects show that the HRV is reduced with the advancing age and also, that there is an autonomic immaturity in neonates, which alters these parameters. This analysis presents interesting perspectives in dogs, however, even before it can be used, it is pertinent to establish a better understanding of the physiological behavior of cardiac autonomic modulation. The objective of this study was to describe a characteristic pattern of cardiac autonomic behavior in healthy dogs in different age groups. Time and frequency domain of HRV were analyzed using Holter and the short-term heart rate monitor in 87 dogs. It was observed that in dogs between one and seven years of age, they present higher HRV when compared to other age groups. Older dogs (> 8 years) had a natural tendency to decrease cardiac parasympathetic markers of HRV, while puppies (<1 year) had a upper sympathetic predominance and, consequently, lower HRV. It is concluded that the balance of the sympathetic and parasympathetic systems, is influenced by age in dogs, changing HRV values in the short term. Therefore, it is extremely important to obtain reference values for future analyzes in different diseases. These analyzes can be performed by the Holter and cardiac frequency meter, even with limitations for dogs, since both evaluate the heart rate variability. / Mestre
207

Efeitos hemodinâmicos e metabólicos do destreinamento no diabetes experimental / Hemodynamic and metabolic effects of detraining in experimental diabetes

Rogow, André 24 November 2008 (has links)
Indivíduos diabéticos estão sujeitos a maior mortalidade cardiovascular relacionadas à disfunção autonômica e à neuropatia. Por outro lado o exercício físico é uma ferramenta importante no tratamento do diabetes, melhorando a função autonômica, melhorando a sensibilidade baroreflexa e quimioreflexa além de melhorar a freqüência cardíaca intrínseca. Os benefícios cardiovasculares e metabólicos do exercício físico em indivíduos diabéticos são bem conhecidos, mas uma questão permanece em aberto: Por quanto tempo esse benefícios são mantidos após a cessação do treinamento físico? O objetivo desse estudo foi avaliar o efeito de 3 semanas de destreinamento nas variáveis autonômicas, metabólicas e cardiovasculares após 10 semanas de treinamento em ratos diabéticos por STZ. Os experimentos foram realizados em ratos Wistar, machos, randomicamente divididos em 6 grupos: controle sedentário (CS), controle treinado (CT), controle treinado-destreinado (CD), diabético sedentário (DS), diabético treinado (DT) e diabético treinado-destreinado (DD). A indução do diabetes foi feita por uma injeção IV de STZ (50-60 mg/kg). O exercício físico de moderada intensidade (50 70% da velocidade máxima de corrida) foi realizado durante 10 semanas, seguidas de 3 semanas de destreinamento. Ao final do protocolo, artéria e veia femoral foram canuladas, pressão arterial (PA) e freqüência cardíaca (FC) foram medidas, de forma direta, gravadas e processadas por um sistema de aquisição de dados (Windaq, 2 kHz). A sensibilidade baroreflexa foi calculada pela razão da FC/PAM, depois da infusão de drogas vasoativas. A análise da potência espectral (FFT) foi calculada pela densidade media dos espectros. O diabetes reduziu a PA, a FC e a sensibilidade do barorreflexo (SBR), o que foi revertido pelo exercício físico e mantido após as 3 semanas de destreinamento. Nos animais controles, o exercício físico diminuiu a PA e a FC e melhorou a SBR, alterações estas que retornaram aos valores basais depois do destreinamento. A variância foi menor no DS quando comparada ao CS. O treinamento físico melhorou a variância no grupo DT enquanto que no grupo DD a variância foi similar a do grupo DS. Nenhuma alteração foi observada nos animais controle não diabéticos. No domínio da freqüência, o componente LF (%) e a razão entre LF/HF foi atenuada no grupo DT e no grupo DD, entretanto essa diferença não foi estatisticamente diferente do grupo DS. Nos animais controle, o exercício físico diminuiu a razão entre LF/HF (balance simpatovagal) e o componente LF enquanto que o componente HF esteve aumentado nos dois grupos: CT e DT. Embora a variância do IP tenha retornado aos valores basais após o destreinamento, nos animais diabéticos, observamos uma relação inversa entre o nível de glicose plasmatica e o componente HF (%) da variância da FC. O diabetes induziu redução da freqüência cardíaca intrínseca quando comparada a todos os grupos controle. O exercício físico reverteu essa alteração, e o efeito persistiu após o destreinamento. Nos animais diabéticos, o exercício diminuiu a glicemia e o destreinamento aumentou-a, mas mesmo assim o nível glicemico ainda ficou menor do que os observados nos animais diabéticos sedentários. Os ratos diabéticos treinados apresentaram 84% de sobrevivência durante as 10 semanas de treinamento enquanto que os diabéticos sedentários apresentaram 62%. Na 13 semana de protocolo, os diabéticos destreinados tiveram 80% de sobrevivência e os diabéticos sedentários 53% de sobrevivência. Esses achados indicam que o exercício físico não é apenas uma importante ferramenta no manejo das disfunções metabólicas e cardiovasculares do diabetes, mas mostra também que a algumas dessas melhoras persistem mesmo após 3 semanas de destreinamento, contribuindo para o aumento da taxa de sobrevida dos grupos treinados e destreinados quando comparados com os sedentários. / Diabetic subjects are prone to increased cardiovascular morbidity and mortality related to autonomic dysfunction and neuropathy. On the other hand, exercise is an important therapeutic tool in the treatment of diabetes improving autonomic function, increasing baro (BRS) and chemoreflex sensitivity and also intrinsic heart rate (IHR). Regarding the benefits of exercise training in cardiovascular and metabolic function in diabetic subjects, a question not yet answered is how long are these benefits kept. The aim of this study was to evaluate the effect of 3 weeks of detraining in the autonomic, metabolic and cardiovascular parameters after a previous period of 10 weeks of training in STZ-diabetic rats. Experiments were performed on male Wistar rats randomly assigned to 1 of 6 groups (n=8 each): sedentary controls (CS), trained controls (CT), traineddetrained controls (CD), sedentary diabetic (DS), trained diabetic (DT) and trained-detrained diabetic (DD). Diabetes was induced by STZ (50 mg/kg. ev). Moderate intensity exercise training (50-70% maximal running speed) was performed during 10 weeks, and 3 weeks for detraining. After femoral vessels catheterization, arterial pressure (AP) and heart rate (HR) were directly obtained, recorded and processed by a data acquisition system (Windaq, 2 kHz). BRS was calculated by the ratio HR/MAP, after infusion of vasoactive drugs. Spectral power (FFT) was calculated by means of power spectrum density integration. Diabetes promoted attenuation in AP, HR as well as in BRS, which was reversed by exercise training and maintained after 3 weeks of detraining. In controls, training decreased AP and HR and improved BRS, changes that returned to baseline values after the detraining. Variance was lower in DS versus CS. Exercise training improved variance in DT while in DD it was similar to DS. No changes were observed in non diabetic controls. In frequency domain the LF (%) component and the LF/HF ratio were attenuated in DT and DD groups, but not statistically different to DS. Exercise training in controls decreased the LF/HF ratio (sympathovagal balance) and LF component while HF component was increased in both CT and DT. Although whole variance of HR returned to basal levels after detraining in diabetic animals, there was an inverse relationship between plasma glucose levels and the HF (%) component of HRV. Diabetes induced IHR reduction in relation to all groups of control animals. Exercise training reversed that change, which was kept after detraining. In diabetes, exercise training lowered glycemia while detraining increased it when compared to trained diabetic, but the glucose levels were still lower than in sedentary diabetic. Diabetic trained rats presented 84% while diabetic sedentary 62% of survival rate in 10 weeks of training protocol. In the 13th week of protocol the diabetic detrained animals had 80% and the diabetic sedentary rats had a survival rate of 53%. These findings indicate that exercise training is not only an effective tool in the management of cardiovascular and metabolic diabetic derangements but also that these changes were kept working even after 3 weeks of detraining, contributing to the increase survival rate of the trained and detrained groups in comparison with sedentary ones
208

Efeitos da periodização do treinamento sobre a modulação autonômica cardíaca e marcadores de estresse endógenos em atletas de voleibol / Effects of training periodization on cardiac autonomic modulation and stress endogenous markers in volleyball players

Mazon, José Henrique 13 September 2011 (has links)
Nós investigamos os efeitos do modelo de periodização de cargas seletivas (MPCS) sobre a modulação autonômica da variabilidade da freqüência cardíaca (VFC) e marcadores de estresse endógenos, antes e após um período de competição, em jogadores de voleibol (N=32). O protocolo experimental para a avaliação da VFC consistiu do uso da análise espectral das séries temporais compostas dos intervalos R-R derivados do eletrocardiograma obtidos na posição supina e durante o teste de inclinação (tilt test). Os níveis dos marcadores de estresse foram determinados pela quantificação da concentração plasmática de catecolaminas endógenas, cortisol e testosterona livre. Os resultados não demonstraram alterações na VFC antes e após o período de competição. Em contraste, a quantificação da concentração plasmática dos marcadores de estresse endógenos revelou reduções nos níveis de catecolaminas totais, noradrenalina e cortisol. Estas mudanças foram acompanhadas por aumentos na concentração de testosterona livre e na razão testosterona/cortisol. Em conclusão, nossos resultados demonstraram que o MPCS não alterou a modulação autonômica da VFC, mas promoveu adaptações benéficas aos atletas, incluindo mudanças positivas na concentração plasmática dos marcadores de estresse endógenos analisados. A ausência de alterações na VFC indica que não houve relação direta entre modulação autonômica cardíaca e marcadores de estresse endógenos no presente estudo. / We investigated the effects of selective loads of periodization model (SLPM) on autonomic modulation of heart rate variability (HRV) and endogenous stress markers before and after a competition period in volleyball players (N=32). The experimental protocol for the evaluation of HRV consisted of using spectral analysis of time series composed of the R-R intervals derived from electrocardiogram obtained in the supine position and during the tilt test. Stress marker levels were determined by quantifying the plasma concentration of endogenous catecholamines, cortisol and free testosterone. The results showed no changes between the levels of HRV before and after a competition period. In contrast, the quantification of the plasma concentration of endogenous stress markers revealed reductions in the levels of total catecholamines, noradrenaline and cortisol. In conclusion, our results demonstrate that the SLPM did not change the cardiac autonomic modulation of HRV, but promoted beneficial adaptations in athletes, including positive changes in the plasma concentration of the endogenous stress markers. The absence of changes in HRV indicates that there is no direct relationship between cardiac autonomic modulation and endogenous stress markers in the present study.
209

Ação central da insulina e do sistema nervoso autônomo sobre a produção hepática de glicose de ratos não anestesiados. / Central action of insulin and the sympathetic nervous system on hepatic glucose production of conscious rats.

Toledo, Izabela Martina Ramos Ribeiro de 04 April 2012 (has links)
A glicose é considerada o combustível mais importante para a manutenção das atividades de diversos tecidos corporais. O fígado é um órgão chave na manutenção da homeostase da glicose e para que isto ocorra é necessária a presença de hormônios, tais como a insulina que pode desempenhar sua função agindo tanto em nível periférico como centralmente. Além disso, estudos demonstram que o sistema nervoso autônomo (SNA) desempenha uma função extremamente importante no controle da glicemia. Sendo assim, o objetivo deste trabalho foi avaliar o efeito da insulina injetada no sistema nervoso central sobre a produção hepática de glicose (PHG), além de verificar o papel do SNA na modulação dessa variável em ratos livres de anestesia. Para isto, utilizamos um modelo animal de hiperatividade simpática, (SHR) e seu controle (Wistar). Antecedendo todos os experimentos, os animais foram mantidos em privação alimentar por um período de 12 h. A insulina e/ou insulina denaturada (controle-veículo) foi injetada no ventrículo lateral (VL) cerebral (100hU/ml) e a PHG, PAM e FC foram monitorados aos 2, 5, 10, 20 e 30 min. subsequentes. No grupo Wistar observamos uma queda máxima na PHG aos 10 min. após a microinjeção de insulina no VL (81,4 mg/dL) quando comparados ao seu valor basal antes da insulina (110mg/dL) e ao grupo controle (insulina denaturada) no mesmo decurso temporal (117,5 mg/dL). Em outro grupo experimental verificamos que o antagonismo periférico dos receptores muscarínicos (metil-atropina, 2mg/Kg, i.v.) foi capaz de bloquear a queda na PHG decorrente da ação central da insulina no mesmo decurso temporal (92mg/dL aos 10\' vs 88mg/dL no basal). Por outro lado, o antagonismo periférico dos receptores adrenérgicos (fentolamina, 3mg/Kg e propranolol, 0,5mg/Kg, i.v., respectivamente) não afetou a queda da PHG após administração da insulina no VL. No grupo SHR a insulina injetada no VL não promoveu alterações na PHG nos tempos avaliados. A PAM e FC não sofreram qualquer alteração após a injeção central de insulina em ambas as linhagens de animais. Para avaliar a função do SNA sobre a PHG basal independente da ação central da insulina de ambas as linhagens realizamos o antagonismo periférico dos receptores adrenérgicos e muscarínicos e a PHG foi monitorada aos 2, 5, 10, 20, 30, 40, 50 e 60 min. subsequentes. Os resultados mostraram que o bloqueio adrenérgico diminuiu a PHG com maior queda aos 40 min. tanto nos animais Wistar (79 mg/dL; -25%) quanto nos SHR (93 mg/dL; -22%) em relação ao basal (Wistar: 106 mg/dL e SHR: 118 mg/dL). O bloqueio periférico dos receptores muscarínicos não alterou a PHG em ambas as linhagens. O conjunto dos resultados obtidos nos leva a concluir que, durante uma situação de jejum prolongado, a alça parassimpática do SNA é a principal responsável pela rápida queda na PHG causada pela ação central da insulina em animais Wistar. Por outro lado, o sistema autonômo simpático desempenha maior influência tônica no controle da PHG basal do que a alça parassimpática, independente da ação central da insulina tanto em SHR quanto em Wistar. / Glucose is considered the most important fuel for the maintenance activities of the tissues. The liver is a key organ in maintaining glucose homeostasis and for this, requires the presence of hormones such as insulin that can perform its function by acting both peripherally and centrally. In addition, studies show that the autonomic nervous system (ANS) plays an extremely important role in glucose control. Therefore, the aim of this study was to evaluate the effect of insulin injected into the central nervous system on hepatic glucose production (HGP), and verifies the role of ANS in the modulation of this variable in conscious rats. For this, we used an animal model of sympathetic hyperactivity (SHR) and its control (Wistar). Preceding all experiments, the animals were kept in starvation for a period of 12 h. Insulin and / or denatured insulin (control vehicle) was injected into the lateral ventricle (LV) of the brain (100hU/ml) and HGP, MAP and HR were monitored at 2, 5, 10, 20 and 30 min. In the Wistar group we observed a maximal drop in PHG 10 min after microinjection of insulin in the VL (81.4 mg / dL) compared to baseline before insulin (110mg/dl) and the control group (insulin denatured) in the same time course (117.5 mg / dL). In another experimental group we found that antagonism of peripheral muscarinic receptors (methyl-atropine 2mg/kg, iv) was able to block the fall in HGP resulting from the action of insulin at the same time course (92mg/dL to 10\' vs 88mg / dL at baseline). On the other hand, the antagonism of peripheral adrenergic receptors (Phentolamine and propranolol 3mg/kg, 0.5 mg / kg, iv, respectively) did not affect the fall of HGP after administration of insulin in the VL. In the SHR group insulin injected into the VL did not promote changes in HGP in the times studied. The MAP and HR did not change after the central injection of insulin in both strains of animals. To evaluate the role of ANS on the baseline HGP independent of central action of insulin in both strains we performed the peripheral antagonism of adrenergic and muscarinic receptors and HGP was monitored at 2, 5, 10, 20, 30, 40, 50 and 60 min. The results showed that the adrenergic blockade reduced the HGP with a greater decrease at 40 min. both in Wistar (79 mg / dL, -25%) and in SHR (93 mg / dL, -22%) compared to baseline (Wistar: 106 mg / dL and SHR: 118 mg / dL). The blockade of peripheral muscarinic receptors did not alter the PHG in both strains. The set of results leads us to conclude that during starvation, the handle of the parasympathetic ANS is primarily responsible for the rapid drop in HGP caused by central action of insulin in Wistar. On the other hand, the autonomic sympathetic system plays a greater influence on the tonic baseline control of HGP than the parasympathetic system, independent of the central action of insulin in both SHR and Wistar.
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Sistema glutamatérgico e nitrérgico do hipocampo dorsal de ratos e a modulação da atividade autonômica durante situações de estresse / The glutamatergic system and nitrérgico of hippocampus of rats and the modulation of autonomic activity during stress situations

Moraes Neto, Teophanes Barbosa 23 August 2011 (has links)
O hipocampo dorsal (HD) é uma estrutura do sistema límbico que está envolvida em processos emocionais, de memória e aprendizado. Alem disso, o HD também exerce influência sobre a atividade autonômica. Durante situações aversivas pode se observar tanto respostas autonômicas (aumento da pressão arterial, frequência cardíaca e queda da temperatura cutânea) quanto comportamentais. O HD está envolvido com diversas alterações associadas a reações defensivas e apresenta conexões com diversas estruturas que modulam essas respostas, fazendo parte de uma via responsável por modular as respostas durante situações aversivas. São observadas aumentos nas respostas autonômicas durante o estresse por restrição (ER). Durante a atividade do HD está aumentada. Além disso, é possível observar aumento dos níveis de glutamato no HD. A ativação de receptores glutamatérgicos do tipo NMDA no sistema nervoso central aumenta a síntese de óxido nítrico (NO) por ativação da isoforma neuronial da óxido nítrico sintase (nNOS). Além disso, esta interação, NMDA/NO, no HD parece ser importante nas reações defensivas. Portanto, no presente estudo nós observamos que a administração de glutamato no HD promove aumentos do sistema cardiovascular, similares a aqueles observados durante situações de estresse. Estas respostas cardiovasculares são associadas com um aumento da atividade simpática. Além disso, os efeitos do glutamato foram inibidos pela administração do AP7, um antagonista NMDA, do N?-Propyl-L-Arginine, um inibidor da nNOS ou do Carboxy-PTIO(S)-3-carboxy-4- hydroxyphenylglicine, um sequestrador de NO. Finalmente, a administração destas drogas foi capaz de reduzir as respostas autonômicas causadas pelo ER. Portanto, nossos achados mostram que o sistema glutamatérgico presente no HD esta envolvido com a modulação autonômica através de receptores do tipo NMDA e a ativação de nNOS. Além disso, esta via NMDA/NO está envolvida na modulação autonômica durante situações de estresse. / The dorsal hippocampus (DH) is a structure of limbic system that is involved in emotional, leaning and memories process. Moreover, the DH also exerts influence on autonomic activity. During aversive situations it is possible observes autonomic responses (increase in blood pressure, heart rate and decrease in cutaneous temperature) associated to defensive behavioral. The DH is involved with alterations associated to defensive reactions and presents connections with several structures which modulate that responses, making part of a pathway involved with behavior and autonomic responses associated with aversive situations. Increase of autonomics responses are observed during restraint stress (RS). During RS the DH activity is increased. Moreover, it is possible observe increases in glutamate levels in DH. In central nervous system the activation of NMDA glutamatergic receptors increases the nitric oxide (NO) synthesis by activate the neuronal isoform of nitric oxide syntase (nNOS). Moreover, this interaction, NMDA/ NO, in the DH appears to important in the defensive reactions. Therefore, in the present work we observed that administration of glutamate in the DH promotes increases of cardiovascular system, similar those observed during stress situation. These cardiovascular responses were associate with an increase of sympathetic activity. Also, the glutamate effects were inhibited by administration of AP7, a NMDA antagonist, N?-Propyl-L-Arginine, a nNOS inhibitor, or Carboxy-PTIO(S)-3- carboxy-4-hydroxyphenylglicine, a NO scavenger. Finally, the administration of these drugs were able to reduces the autonomic responses evoked by RS. Therefore, our findings showed that glutamatergic system present in DH are involved with autonomic modulation through NMDA receptors and nNOS activation. Moreover, this NMDA/ NO is involved with autonomic modulation during stress situation.

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