Introdução: A vulnerabilidade dos profissionais de enfermagem ao estresse está associada à exposição crônica aos estressores cotidianos de trabalho e, consequentemente, aos efeitos cumulativos dos mediadores primários e secundários do estresse. Embora vários estudos tenham relatado o elevado nível de estresse dos profissionais de enfermagem, pouco se sabe a respeito das implicações biológicas do estresse no trabalho, expressas na carga alostática e no ritmo de secreção dos hormônios de cortisol um dos principais hormônios do estresse. Isto particularmente é importante visto que a carga alostática aumenta o risco do indivíduo desenvolver transtornos relacionados ao estresse como síndromes cardiovasculares, metabólicas, endócrinas, emocionais e cognitivas. Neste sentido, questiona-se se os profissionais de enfermagem apresentam sobrecarga do sistema adaptativo de reação do estresse (carga alostática), bem como alterações no ritmo de secreção de cortisol (hiper ou hipocortisolemia) ao longo do dia e o risco para o desenvolvimento de doenças relacionadas ao estresse. Objetivo: Descrever a frequência de profissionais de enfermagem com carga alostática elevada e ritmo atípico de secreção de cortisol. Analisar se a carga alostática elevada está associada ao ritmo atípico de secreção de cortisol. Método: Foram incluídos 142 profissionais de enfermagem do turno diurno randomicamente selecionados, alocados nas unidades ambulatório, clínica médica, clínica cirúrgica, centro cirúrgico, pronto socorro infantil e adulto, unidade de terapia intensiva adulto e pediátrica de um hospital universitário. Para avaliação do padrão diurno de secreção de cortisol foram coletadas amostras de saliva em dois dias úteis consecutivos de trabalho e, para a análise dos biomarcadores foram coletadas, em um único dia, amostras de sangue de todos os participantes, bem como, verificada sua pressão arterial e medidas antropométricas. A carga alostática foi analisada por mediadores neuroendócrinos, metabólicos, cardiovasculares e imunológicos. Os dados foram armazenados e analisados utilizando o programa estatístico SPSS versão 14.0 e o nível de significância adotado foi de 5%. Resultados: 31% dos profissionais de enfermagem apresentaram padrão atípico (inconsistente ou flat) de secreção de cortisol e 47,2% carga alostática elevada. Não houve associação entre o ritmo de secreção de cortisol e a carga alostática. Conclusão: Quase metade dos profissionais de enfermagem apresentaram sinais de desgaste do sistema biológico regulador da resposta de estresse, sugerindo que o trabalho possa estar associado a esta sobrecarga e destacando a vulnerabilidade destes trabalhadores ao desenvolvimento de doenças relacionadas ao estresse / Background: The vulnerability of nursing professionals to stress is associated with chronic exposure to everyday stressors and, therefore, with the cumulative effects of primary and secondary stress mediators. Despite the fact that several studies have reported the high stress level of nursing professionals, little is known about the biological implications of stress at work, expressed in the allostatic load and in the rhythm of cortisol secretion, one of the main hormones of stress. This is especially important since the allostatic load increases the risk of an individual to develop stress-related disorders like cardiovascular syndromes, metabolic, endocrine, cognitive and emotional. In this aspect, there are questions whether the nursing professionals present overload on the stress adaptive reaction system (allostatic load), as well as, changes in the rhythm of cortisol secretion (hyper or hypocortisolemia) throughout the day and the risk of developing stress-related diseases. Objective: To describe the frequency of nursing professionals with high allostatic load and atypical rhythm of cortisol secretion. To analyze whether the high allostatic load is associated with atypical rhythm of cortisol secretion. Methods: We included 142 nursing professionals day shift randomly selected, allocated in the outpatient units, medical clinic, surgical clinic, surgery, children and adults emergency room and adult intensive care unit in a pediatric teaching hospital. To evaluate the daytime pattern of cortisol secretion, saliva samples were collected in two work day and, for the analysis of biomarkers, were collected in a single day, blood samples from all participants, as well as, checked his blood pressure and anthropometric measurements. Allostatic load was analized by neuroendocrine, metabolic, cardiovascular and immune mediators. The data was stored and analyzed using the program SPSS version 14.0 and the statistical significance level adopted was 5%. Results: 31% of nursing professionals showed atypical pattern (inconsistent or \"flat\") of secretion of cortisol and 47.2% showed high allostatic load. There was no association between the rate of secretion of cortisol and the allostatic load. Conclusion: Nearly half of nursing professionals showed signs of wear in the biological system stress response regulator, suggesting that the job can be associated with this overload and highlighting the vulnerability of these workers to the development of stress-related diseases.

Orientadores: Felix Guillermo Reyes Reyes, Claudio Antonio Barbosa de Toledo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-17T12:09:40Z (GMT). No. of bitstreams: 1 Freitas_ThaisFernandaPintodeAlmeida_M.pdf: 1160984 bytes, checksum: b9379e4fd16f451c0710b2ca37537085 (MD5) Previous issue date: 2011 / Resumo: Alimentar-se faz parte da cultura do ser humano nao estando unicamente associado a necessidades fisiologicas. Um alimento e constituido de diversas moleculas dentre elas os aminoacidos. O glutamato (GLU) e o anion de um dos principais aminoacidos encontrados nos alimentos que, alem de fazer parte da composicao dos alimentos, e uma molecula essencial para a fisiologia do ser humano. Pode tambem ser ingerido devido ao uso do aditivo alimentar glutamato monossodico (MSG). O GLU desempenha inumeras funcoes no organismo, dentre elas podemos citar: neurotransmissor excitatorio do sistema nervoso central, precursor de GABA e de aminoacidos como prolina e glutamina. Como neurotransmissor o GLU atua sobre quatro tipos de receptores: ionotropicos (AMPA, Kainato e NMDA) e metabotropicos (mGluR1-mGluR8) divididos em tres grupos de acordo com a sua homologia genetica e mecanismos de acao. Esses receptores estao presentes em praticamente todo o sistema nervoso central (SNC) e em outros orgaos como coracao, pulmao e intestino. O MSG e utilizado como realcador de sabor em todo o mundo, sendo que o descobrimento do gosto basico conferido pelo glutamato propiciou a producao industrial do seu sal, glutamato monossodico. O gosto basico conferido pelo glutamato e denominado de Umami, que traduzido do japones significa gosto bom, delicioso. Existem inumeros estudos sobre o uso do MSG como aditivo alimentar (funcao tecnologica), assim como sobre sua funcao fisiologica e seus efeitos no organismo de mamiferos. Organizacoes internacionais e agencias de regulamentacao de muitos paises tem reportado e/ou avaliado que o uso do MSG como aditivo alimentar e seguro. Todavia, alguns autores tem relatado efeitos adversos no sistema nervoso central (SNC) associados a exposicao ao MSG. Assim, o presente estudo teve como objetivo exibir dado morfologico sobre a localizacao do receptor mGluR8 no nucleo arqueado do hipotalamo (NARC) de ratos Wistar e avaliar o efeito da ingestao de dietas adicionadas de diferentes concentracoes de MSG (0% (controle), 1%, 2,5% e 5%) sobre o mGluR8. Tambem foi avaliado o ganho de peso corporeo entre os grupos de animais alimentados com as dietas adicionadas de diferentes concentracoes de MSG. Para evidenciar a presenca do receptor mGluR8 foi utilizada a tecnica de imunohistoquimica. Para avaliar o ganho de peso corporeo os animais foram pesados semanalmente. Todos os dados, tanto da contagem celular da tecnica de imunohistoquimica quanto da pesagem, foram analisados por analise de variancia. Os resultados obtidos indicam nao haver diferenca significativa (p <0,05) entre os ratos que ingeriram as dietas adicionadas das diferentes concentracoes de MSG, tanto para o ganho de peso corporeo como para a presenca de receptores mGluR8 no nucleo arqueado do hipotalamo (NARC) / Abstract: Food is part of human culture not only associated to physiological needs. Food is composed of several molecules among them amino acids. Glutamate (GLU) is the anion of one of the main amino acids found in foods that, besides being part of the food composition, is a molecule essential for human physiology. It can also be ingested due to the use of the food additive monosodium glutamate (MSG). The GLU performs many functions in the body, among them we could mention: excitatory neurotransmitter in the central nervous system, precursor of GABA and other amino acids such as proline and glutamine. As a neurotransmitter GLU acts on four types of receptors: ionotropic (AMPA, NMDA and kainate) and metabotropic (mGluR1-mGluR8) divided into three groups according to their genetic homology. These receptors are present in nearly all central nervous system (CNS) and other organs such as heart, lung and intestine. MSG is used as a flavor enhancer all over the world. The discovery of the basic taste due to glutamate, led to the industrial production of its salt, monosodium glutamate. The basic taste induced by glutamate is called Umami, which translated from Japanese, means good taste, delicious. There are numerous studies on the use of MSG as a food additive (technological function), as well as its physiological functions and its effects in the organism. International organizations and regulatory agencies of many countries have reported and / or evaluated that the use of MSG as a food additive is safe. However, some authors have reported adverse effects associated with exposure to MSG. Thus, this study aimed to assess the presences of the metabotropic receptor mGluR8 in the arcuate nucleus of the hypothalamus (ARH) of Wistar rats, and to evaluate the effects in the mGluR8 receptor resulting from the dietary intake of different concentrations of MSG (0% [control], 1%, 2 , 5% and 5%) during 90 days. Also, it was evaluated the body weight gain of the rats fed with the diets containing MSG in the different concentrations. To demonstrate the presence of the mGluR8 receptor immunohistochemistry technique was employed, and in order to elucidate the weight gain, the animals were weighed weekly. All the data, cell counts from the immunohistochemistry technique and from the rats weighing, were evaluated by analysis of variance. The results showed no significant difference (p<0.05) for both: body weight gain and the presence of mGluR8 receptors among the animals that were fed with the diets containing the different MSG levels / Mestrado / Engenharia de Alimentos / Mestre em Ciência de Alimentos

O córtex pré-frontal (PFC) participa do controle do comportamento de busca por droga e se projeta para a coluna rostrolateral da substância cinzenta periaquedutal (PAGrl) que por sua vez se projeta para o sistema orexinérgico da área hipotalâmica lateral (LHA) que controla comportamentos que oferecem recompensa através de projeções para o sistema dopaminérgico mesolímbico. O objetivo do trabalho é investigar a participação da PAGrl e a sua relação com o PFC e com o sistema orexinérgico da LHA na expressão do comportamento de busca por droga. Submetemos ratos Wistar ao condicionamento de preferência por lugar para sulfato de morfina e notamos que o PFC, a PAGrl e a LHA estão ativados em animais que expressaram tal comportamento. Após, realizamos lesões neuroquímicas bilaterais no PFC e notamos a ausência da busca pela droga nestes animais e da diminuição da ativação da PAGrl e do sistema orexinérgico da LHA. Posteriormente realizarmos lesões neuroquímicas por NMDA na PAGrl e notamos a ausência do comportamento e diminuição de duplas marcações para Fos e orexina na LHA. Os resultados indicam que a PAGrl exerceria um papel crítico para o comportamento de busca por droga, integrando aferências provenientes do PFC para modular os neurônios orexinérgicos da LHA. / The prefrontal cortex (PFC) is involved with planning of the drug seeking behavior and projects itself to the rostrolateral periaqueductal gray (PAGrl) that through projections for the orexin neurons in the lateral hypothalamic area (LHA), participates in the control of behavior that offer rewards. The LHA controls drug reward through projections for the mesolimbic dopaminergic system. This study aims to investigate the relationship between the PFC, PAGrl and orexin neurons in the LHA in drug seeking behavior. We did a morphine conditioned place preference (CPP) procedure in intact, bilateral PAGrl-lesioned and bilateral PFC-lesioned Wistar rats and investigated the pattern of Fos expression. The intact animals displayed such behavior and presented an increase in Fos activation in the PFC, rlPAG and LHA orexinergic neurons. Conversely, PAGrl-lesioned and PFC-lesioned animals did not display this behavior and reduced the activation of orexin neurons in the LHA. PFC-lesioned animals presented a reduction of the Fos activation in the rlPAG. The results suggest a pathway involving the PFC, PAGrl and LHA orexinergic cell group underlying the CCP, where the rlPAG would integrate inputs from the PFC to control the LHA orexinergic cell group.

Estudos apontam a substância cinzenta periaquedutal (PAG) como um sítio crítico para a expressão de vários comportamentos motivados. A porção rostrolateral da PAG (PAGrl), tem um papel chave na regulação da motivação na caça predatória, e modularia mecanismos de recompensa associados ao comportamento alimentar e busca por droga, a partir de projeções para área tegmental ventral e núcleo acumbens; o que dependeria da ligação com neurônios orexinérgicos da área hipotalâmica lateral (LHA). A PAGrl, está mobilizada nos comportamentos de busca por droga assim como na caça predatória. As principais regiões que aferentam a PAGrl são áreas do córtex pré-frontal medial (mPFC) onde a PAGrl integraria tais aferencias e modularia a LHA. Os resultados corroboram com a hipótese, pois lesões no mPFC diminuíram a busca por droga e vimos que neurônios da PAGrl mobilizados no comportamento, que recebem aferências do mPFC, seriam os mesmos que se projetam para LHA e que a PAGrl teria papel crítico na promoção do comportamento de busca por droga no CPP para sulfato de morfina. / Studies show a periaqueductal gray (PAG) as a critical place for an expression of motivated behaviors. The rostrolateral portion of PAG (PAGrl), is a key role in the regulation of motivation in predatory hunting, and modulates, reward mechanisms associated with drug and food seeking, through projections to ventral tegmental area and the nucleus accumbens; what would depend on the connection with orexin neurons of the lateral hypothalamic area (LHA). The PAGrl, is mobilized in predatory hunting as drug seeking. The main region that sends projections to PAGrl is the medial prefrontal cortex (mPFC), where PAGrl integrate such afferent and modulates the LHA. Our results corroborate the hypothesis, because mPFC injuries, decreased drug seeking and we observed that PAGrl neurons mobilized in behavior, and also receive afferents from mPFC, would be the same as projecting to LHA, thus PAGrl had critical role in promotion of drug seeking behavior during the CPP for morphine sulfate.

Vários estudos têm sugerido que o estresse pode ser um dos fatores relacionados com à grande variabilidade cognitiva observada em idosos. Esta associação se explica porque o cortisol, principal classe de hormônios do estresse em humanos, apresenta alta afinidade por receptores específicos localizados no hipocampo, amígdala e região pré-frontal, estruturas associadas ao aprendizado e à memória. Concentrações cronicamente elevadas de cortisol estão associadas à atrofia hipocampal e baixo desempenho cognitivo. Entretanto, o efeito do estresse agudo no desempenho da memória ainda se encontra inconclusivo em idosos. Isto é particularmente relevante, uma vez que, idosos com comprometimento cognitivo patológico apresentam concentração elevada de cortisol, que por sua vez, está associada com rápida progressão da doença. Assim, o objetivo do estudo foi analisar a relação entre desempenho da memória e resposta neuroendócrina e cardiovascular de estresse em idosos saudáveis. Foram selecionados aleatoriamente 100 idosos alfabetizados, predominantemente do sexo feminino, sem prejuízo cognitivo e funcional, moradores da cidade de São Paulo. A resposta neuroendócrina de estresse foi avaliada a partir concentração de cortisol salivar enquanto que a reação cardiovascular a partir da pressão arterial e frequência cardíaca antes, durante e após a exposição do participante a um estressor psicossocial agudo (Trier Social Stress Test TSST). O TSST envolve duas tarefas: falar em público e realizar cálculos aritméticos mentalmente diante de uma banca examinadora. O desempenho da memória foi avaliado mediante aplicação do teste Pares de Palavras (PP) 20 minutos antes do TSST para evocação imediata e aprendizado e 15 minutos após o fim do TSST para evocação tardia. Foi observado aumento de 96% na concentração de cortisol 15 minutos após o TSST, bem como elevação da pressão arterial em relação à situação basal. Ademais, observamos redução significativa do escore do teste PP após o TSST e correlação negativa entre concentração de cortisol, evocação imediata e tardia dos PP. Os resultados revelam influência do estresse agudo no desempenho da memória, particularmente da evocação tardia, de idosos, destacando a vulnerabilidade destes indivíduos aos efeitos neurotóxicos do cortisol na memória e, consequentemente ao desenvolvimento de transtornos cognitivos. / Several studies have suggested that stress may be a factor related to cognitive variability observed in the elderly. This association exists because cortisol, the main class of stress hormones in humans, has a high affinity to specific receptors located in the hippocampus, amygdala and prefrontal regions, structures associated with learning and memory. Chronically elevated cortisol concentrations are associated with hippocampal atrophy and low cognitive performance. However, the effect of acute stress on memory performance is still inconclusive in the elderly. This is particularly relevant, since elderly patients with pathological cognitive impairment present high cortisol level, which in turn is associated with rapid disease progression. The objective of the study was to analyze the relationship between memory performance and neuroendocrine as well as cardiovascular response stress in healthy elderly. One hundred elderly randomly selected, literate, predominantly female, with no cognitive impairment and functional, residents of the city of São Paulo were included. The neuroendocrine response to stress was evaluated using salivary cortisol while the cardiovascular reactivity was assessed through blood pressure and heart rate measured before, during and after exposure to a participant\'s acute psychosocial stressor (\"Trier Social Stress Test\" - TSST). The TSST involves two tasks: public speaking and performing mental arithmetic in front of an examining board. The memory performance was evaluated by the Pairs of Words test (PW) 20 minutes before the TSST for immediate recall and learning and 15 minutes after the end of TSST for delayed recall. It was observed an increase of 96% in the cortisol concentration 15 minutes after the TSST, as well as increased blood pressure compared to baseline. Furthermore, we observed significant reduction in the PP score after TSST and negative correlation between cortisol concentration, immediate and delayed recall of PP. The results revealed influence of acute stress on memory performance, particularly to delayed recall, of older adults, highlighting the vulnerability of older adults to the neurotoxic effects of cortisol on memory and, therefore, to the development of cognitive disorders.

A redução na pressão parcial de O2 é detectada pelos quimiorreceptores periféricos que sinalizam ao sistema nervoso central para que haja uma correção na homeostasia. Estudos neuroanatômicos mostram que neurônios C1 enviam projeções para núcleo paraventricular do hipotálamo (PVH), mas, pouco descrevem a participação desta via em uma situação de hipóxia. Ademais, o envolvimento de mecanismos neuroimunes no controle neural cardiorrespiratório durante a hipóxia não está esclarecido. Neste estudo mostramos que neurônios catecolaminérgicos do BVLr/C1 ativados por hipóxia se projetam para o PVH, e que a integridade destes neurônios é essencial para que neurônios do PVH sejam ativados por hipóxia. Além disso, o tratamento com minociclina alterou a expressão de mediadores inflamatórios no BVLr e PVH, a expressão de Fos e as repostas respiratória e autônoma desencadeadas pela hipóxia. Estes resultados conferem uma importante caracterização sobre a distribuição dos neurônios catecolaminérgicos do BVLr/C1 que são ativados por hipóxia e se projetam para o PVH. Além de mostrar que a hipóxia pode desencadear mecanismos neuroimunes que possivelmente envolvem a participação da microglia e também recrutam a via neural C1- PVH. / The reduction in the O2 partial pressure is detected by the peripheral chemoreceptors that send information to central nervous system to correct the homeostasis. Neuroanatomical studies show that C1 neurons send projections to the paraventricular hypothalamic nucleus (PVH), but rather describe the involvement of this pathway in a hypoxic situation. Furthermore, the potential involvement of neuroimmune mechanisms in cardiorespiratory neural control during hypoxia is unclear. In this study we show that catecholaminergic neurons localized in rostral ventrolateral medulla (RVLM) / C1 cells activated by hypoxia send projections to the PVH, and the integrity of these neurons is essential for PVH neurons be activated by hypoxia. Moreover, treatment with Minocycline changed the expression of inflammatory mediators in RVLM and PVH, the expression of Fos in these nucleus, and respiratory and autonomic responses elicited by hypoxia. These findings provide an important characterization of the distribution of catecholaminergic RVLM / C1 neurons that are activated by hypoxia and project to the PVH. In addition to showing that hypoxia can trigger neuroimmune mechanisms that possibly involve the microglia activity and also recruit the C1/PVH neural pathway.

Orientador: Marcio Alberto Torsoni / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-19T01:35:33Z (GMT). No. of bitstreams: 1 Roman_ErikaAnnedeFreitasRobles_D.pdf: 2154456 bytes, checksum: 96e67ff457e13cf663c712d985a8be21 (MD5) Previous issue date: 2011 / Resumo: Sobrepeso e obesidade são caracterizados por um aumento de tecido adiposo corpóreo, que resulta da interação entre muitos fatores, incluindo genéticos, metabólicos, comportamentais e ambientais. A obesidade está relacionada ao desenvolvimento de diabetes mellitus do tipo 2 (DM2). O principal mecanismo envolvido na associação entre obesidade e DM2 é a indução de uma resposta inflamatória subclínica capaz de gerar resistência à insulina. Este fenômeno é caracterizado pela capacidade reduzida deste hormônio em promover a homeostase glicêmica. O músculo esquelético (SM) é considerado um dos principais tecidos para a homeostase da glicose, já que ele responde por cerca de 80 % da captação total de glicose estimulada pela insulina no corpo. Sendo assim, a resistência à insulina em músculo esquelético é o maior determinante da hiperglicemia e DM2. Por outro lado, a leptina apresenta função crucial na homeostase glicêmica por agir no cérebro e sua ação neste órgão requer a atividade da PI3K para modular a homeostase da glicose e o metabolismo periférico. Contudo, o mecanismo envolvido neste fenômeno não é completamente entendido. Neste estudo nós aventamos a hipótese que a atividade hipotalâmica da PI3K é importante para a modulação da via da quinase dependente de AMP (AMPK)/acetil-CoA carboxilase (ACC), PGC1? e AKT em músculo esquelético. Para investigar esta questão, injetamos leptina no ventrículo lateral do hipotálamo de ratos. A leptina (ICV) aumentou a fosforilação da JAK2 (80 %) e AKT (350 %) hipotalâmica, quando comparado ao grupo controle. A administração prévia de LY294002 (inibidor químico da PI3K) reduziu a fosforilação da AKT hipotalâmica, induzida por leptina ICV. Adicionalmente, a leptina (ICV) melhorou a tolerância à glicose no GTT (50 %), mas a administração prévia de propranolol (10 mg/kg IP) ou LY294002 (1nmol-ICV) reduziu este efeito. Em músculo soleus a fosforilação da AKT, estimulada pela insulina, foi maior no grupo leptina (200 %) do que no grupo controle, contudo a administração prévia de propranolol (IP) reduziu (50 %) este efeito. Como o propranolol a administração prévia de LY294002 (ICV) reduziu (45 %) o efeito da leptina (ICV) sobre a fosforilação da AKT em músculo esquelético. A fosforilação da JAK2, em músculo esquelético, foi maior no grupo leptina (ICV) do que no grupo controle, mas a administração prévia de LY294002 (ICV) bloqueou este efeito. Adicionalmente, a ação central da leptina aumentou a expressão de PGC1? e a fosforilação da AMPK e ACC em músculo soleus. A administração prévia de LY294002 bloqueou estes efeitos. Concluímos que a ativação da via da PI3K hipotalâmica, induzida pela leptina, é importante para a fosforilação da AKT, bem como para a ativação de vias catabólicas através da AMPK e PGC1? em músculo esquelético. Assim, um defeito na via de sinalização da PI3K no hipotálamo pode contribuir para a resistência periférica à insulina associada à obesidade induzida por dieta / Abstract: Overweight and obesity are characterized by an increased body fat and result from the interaction of many factors, which include genetic, metabolic, behavioral, and environmental ones. Obesity is a clinical condition highly associated with type 2 diabetes mellitus (DM2). The major reason for the link between obesity and DM2 is the induction of a subclinical inflammatory response which leads to insulin resistance. This phenomenon is characterized by the reduced ability of the pancreatic hormone insulin to promote glucose homeostasis. Skeletal muscle (SM) is considered as one of the most important tissues in glucose homeostasis, because it accounts for 80 % of whole body insulin-stimulated glucose uptake. Therefore, skeletal muscle insulin resistance is a major determinant of hyperglycemia and DM2. In addition, leptin plays a central role in glucose homeostasis acting in the brain and its action in this organ requires PI3K activity to modulate glucose homeostasis and peripheral metabolism. However, the mechanism behind this phenomenon is not clearly understood. We hypothesize that hypothalamic PI3K activity is important for the modulation of AMP-activated protein kinase (AMPK)/acetil-CoA carboxylase (ACC) pathway, PGC1?, and AKT in skeletal muscle. To address this issue, we injected leptin into the lateral ventricle of rats. ICV leptin increased the phosphorylation of hypothalamic JAK2 (80 %) and AKT (350 %) when compared to the control group. Previous ICV LY294002 (chemical inhibitior of PI3K) administration reduced hypothalamic AKT phosphorylation, induced by ICV leptin. In addition, ICV leptin improved the clearance of glucose in GTT (50%), but the previous administration of propranolol (10 mg/kg bw-IP) or ICV LY294002 (1nmol-ICV) reduced this effect. In the soleus muscle, the AKT phosphorylation, stimulated by insulin, was higher in leptin group (200 %) than the control group, but the previous administration of propranalol (IP) reduced (50 %) this effect. Like propranalol the previous administration of LY294002 (ICV) reduced (45 %) the effect of ICV leptin on AKT phosphorylation in the skeletal muscle. JAK2 phosphorylation, in skeletal muscle, was higher in leptin (ICV) group than the control group, but the previous ICV administration of LY294002 blocked this effect. Additionally, the central action of leptin increased PGC1? expression, AMPK and ACC phosphorylation in the soleus muscle. Previous ICV administration of LY294002 blocked these effects. We conclude that the activation of hypothalamic PI3K pathway is important for leptin-induced AKT phosphorylarion, as well as for an active catabolic pathway through AMPK and PGC1? in skeletal muscle. Thus, a defective leptin signaling PI3K pathway in the hypothalamus may contribute to peripheral resistance to insulin associated to diet-induced obesity / Doutorado / Fisiologia / Doutor em Biologia Funcional e Molecular

Le travail de cette thèse s’inscrit dans le cadre du projet ANR SUSoSTRESS qui a pour objectif la compréhension des mécanismes moléculaireset génétiques sous-jacents à la variabilité individuelle de réponses de stress et a collecté des données longitudinales à plusieurs niveaux biologiquessur une population d’étude porcine (race Large White). La thèse est organisé en deux partie. La première partie s’articule autour de l’analyse de données cliniques et transcriptomiques collectées à plusieurs pas de temps avant et après application de deux types de stress : injection d’ACTH et de LPS. Dans cettepartie, on cherche à développer d’un modèle fonctionnel permettant de décrire et d’intégrer au mieux l’ensemble des sources de variation génétique du fonctionnement de l’axe corticotrope et plus généralement des réponses de stress dans notre population d’étude. Plus précisément, il s’agit d’élaborer un modèle (au sens biologique du terme) décrivant les différentes réponses biologiques de stress et l’influence des variations génétiques (simples et en interaction), dans le but de prédire les leviers les plus efficaces en fonction de l’objectif de sélection. Ce travail a mis en évidence une liste de 65 gènes différentiellement exprimé au cours des réponses au stress, dont un ensemble de 8 gènes liés au au cortisol (l’hormone principale du stress) par NR3C1, le récepteur aux glucocorticoides. Ces gènes sont des biomarqueurs potentiels pouvant être fournis aux éleveurs en tant que leviers de sélection permettant un meilleur équilibre entre amélioration des caractères de production et des caractères de robustesse. La deuxième partie de ce travail s’articule autour du développement d’un outil d’analyse statistiques adapté à l’intégration de données ’omiques longitudinalesavec une variable cible d’intérêt.Nous proposons la «multiway-SIR », qui étend la méthode dual-STATIS, une méthode d’analyse de données cubiques non supervisée, au cadre de la SIR, une méthode de régression semi-paramétrique pouvant être utilisée à des fins exploratoires. Cette méthode est appliquée sur les données cliniques de l’expérience d’ACTHet permet d’y explorer l’influence de la variabilité de la réponse du cortisol à une injection d’ACTH. / This PhD thesis is part of the SUSoSTRESS project. This ANR funded project aims at improving the knowledge about molecular and genetic mechanisms underlying inter-individual variability in stress responses. Longitudinal data were collected at several biological levels on a porcine population (Large White). This work is structured in 2 parts. The first part is built around clinical and transcriptomic longitudinal data analyses collected before and after 2 types of stress factors : ACTH and LPS injection. The aim of this contribution is to develop a functional model describing all sources of genetic variation in the HPA axis activity and in stress responses in our study population.More precisely, it aims at defining a model describing the different biological stress responses and the influence of genetic variations in order to identify the most efficient selection levers according to selection goals. This work allowed for the identification of 65 differentially expressed genes during stress responses. Among them, 8 genes were highly linked to cortisol (the main stress hormone) through NR3C1 (glucocorticoid receptor (GR)). These genes are potential biomarkers and can be communicated to breeders as selection levers for a better trade-off between production and robustness traits in farmanimals. The second part is built around the development of a statistical tool suited for the data integration of repeated omicmeasurements with a real target variable.We introduce the "multiway-SIR" approach which extends the dual-STATIS (an approach to study 3-way datasets) method to the SIR framework (a semi-parametric regression model that can be used in an exploratory way). This method is illustrated on clinical data from the ACTH experiment. It allows for the exploration of the link between clinical variable response over time and inter-individual variability in the cortisol response to an ACTH injection.

BACKGROUND: Obesity is a leading health burden of the 21st century. Alterations of the individual endocrine stress response and the monoamine system may pathophysiologically contribute to the obesity pandemic and its metabolic and mental complications. OBJECTIVES: (i) to measure hypothalamic-pituitary-adrenal (HPA) axis responsiveness and its relation to serum concentrations of the arginine-vasopressin (AVP) surrogate copeptin in subjects with obesity (OB) compared to non-obesity controls (NOC), (ii) to test whether HPA axis responsiveness and copeptin are related to central noradrenaline (NA) transporter (NAT) availability, (iii) to assess brain serotonin transporter (SERT) binding potentials in OB compared to NOC. METHODS: 40 subjects with obesity (BMI > 35kg/m2) were compared to 25 non-obesity controls, matched for age and sex. (i) All individuals underwent the combined dexamethasone/corticotropin releasing hormone (dex/CRH) test. Plasma ACTH and cortisol curve parameters were derived, and copeptin was assessed in the 1500h sample. (ii) Positron emission tomography (PET) was applied in 10 OB and 10 NOC using the NAT-selective radiotracer S,S-[11C]O-methylreboxetine (MRB) and associated to curve indicators derived from the dex/CRH test as well as to copeptin. (iii) PET using the SERT selective radiotracer [11C] DASB was performed in 30 OB and 15 NOC for intergroup comparison. RESULTS: (i) OB subjects showed an increased HPA axis responsiveness as measured by cortisol concentrations after CRH stimulation. Correspondingly, the AVP surrogate copeptin was higher in OB along with being significantly associated to HPA axis reactivity. OB subjects had a higher adrenal sensitivity as measured by a lower ACTH/cortisol ratio. (ii) In NOC, the HPA response was related to NAT availability of the amygdala and the orbitofrontal cortex while in OB, this association was located in the hypothalamus. (iii) There were no differences in SERT availability between OB and NOC, but a higher inter-regional SERT connectivity was observed in OB. CONCLUSION: This work supports the notion of an increased endocrine stress response in human obesity, pointing to interacting alterations of the HPA and neurohypophyseal axes. Normally, these stress axes seem to be linked to prefrontal-limbic NA signaling, whereas a loss of this association in favor of a hypothalamic-centered relation is observed in OB. The SERT network pattern is more closely inter-related in OB, albeit central SERT concentrations per se do not differ between OB and NOC.:ABBREVIATIONS 4 LIST OF FIGURES 5 I. BIBLIOGRAPHIC DESCRIPTION 6 II. INTRODUCTION 7 2.1 Obesity as a global health burden 7 2.2 Neurobiology of stress 8 2.3 Stress and obesity 8 2.4 Neuroendocrine correlates of the stress response – The hypothalamic pituitary-adrenaland neurohypophyseal axes 9 2.4.1 Anatomy of the hypothalamic-pituitary-adrenal and neurohypophyseal axes 10 2.4.2 The role of CRH, ACTH and cortisol in the context of metabolism and obesity 11 2.4.3 The role of AVP in the context of metabolism and obesity 12 2.4.4 Measuring HPA axis responsiveness by means of the combined dexamethasonecorticotropin-releasing hormone (dex/CRH) test 12 2.4.5 Measuring AVP secretion by its equally-released surrogate copeptin 14 2.5 The noradrenergic system in the context of obesity and stress axis modulation 14 2.5.1 NA and its influence on feeding behavior16 2.5.2 The association of the noradrenergic system with the HPA and neurohypophyseal axes 16 2.5.3 Monoamine transporters as regulators of neurotransmitter signaling 17 2.5.4 Noradrenaline transporter imaging 18 2.6 The serotonergic system in obesity 19 2.6.1 Role of serotonin in the context of feeding behavior and metabolism 20 2.6.3 5-HTT imaging 21 2.7 Objectives and hypotheses 22 2.8 Study design 23 III. RESULTS 24 3. 1 Post-dexamethasone serum copeptin corresponds to HPA axis responsiveness in human obesity 24 3. 2 Central noradrenaline transporter availability is linked with HPA axis responsiveness and copeptin in human obesity and non-obese controls 34 3. 3 Central serotonin transporter availability in highly obese individuals compared with nonobese controls: A [11C] DASB positron emission tomography study 46 IV. SUMMARY 56 4.1 Subjects with obesity show an enhanced HPA axis responsiveness which correlates to serum concentrations of the AVP surrogate copeptin and abdominal fat distribution 56 4.2 HPA axis responsiveness and copeptin concentrations are differentially related to central NAT availability in subjects with obesity compared to non-obesity controls 58 4.3 Central serotonin transporter availability does not significantly differ in subjects with obesity compared to their non-obesity counterparts 59 4.4 Future direction 61 V. References 62 VI. APPENDICES 79 6.1 Curriculum vitae 79 6.2 Publications 81 6.3 Scientific contribution of the doctoral candidate to the publications 82 6.4 Declaration of the independent writing of this thesis 83 6.5 Acknowledgements 84

Posttraumatic stress disorder (PTSD) is a trauma-related disorder that may develop in response to traumatic or stressful events. Dysfunction of the Hypothalamic-Pituitary-Adrenal (HPA) axis has been implicated in the disorder. Studies support such dysfunction as being a consequence of PTSD, rather than a precursor. However, most studies of the HPA are either cross-sectional or have been carried out in adults. The aim of the present study was to identify whether HPA dysregulation interacts with stressful experiences to increase the likelihood of developing PTSD symptoms in a community-recruited sample of healthy adolescent girls. Adolescent girls (N = 550) and one of their parents participated. Adolescents’ clinical symptoms were assessed at baseline and at a nine month follow-up. Saliva samples were collected from all adolescent participants at waking, 30 minutes after waking, and 8 pm on 3 consecutive days. Flattened diurnal slope of cortisol at baseline was associated with increased PTSD symptoms nine months later. Baseline cortisol awakening response (CAR) per se was not prospectively related to developing PTSD symptoms, but its interactions with stressful experience was associated with elevated PTSD symptoms at follow-up. Effects were small and need to be replicated in samples with more severe stressors, as well as more clinical levels of PTSD. Nevertheless, findings suggest that dysregulated basal HPA functioning may be involved in the development of PTSD symptoms.