Respostas adaptativas ao estresse podem ser acompanhadas por alterações nos comportamentos emocionais, em particular relacionados com medo e ansiedade, bem como alterações na sensibilidade dolorosa. Ainda, tem sido investigado o papel do óxido nítrico em áreas encefálicas relacionadas ao comportamento defensivo. Embora várias evidências têm demonstrado que o enriquecimento ambiental promove melhora nos processos de memória, no aprendizado e em respostas nociceptivas, a relação entre o estresse crônico e as vantagens da utilização do enriquecimento ambiental ainda são pouco investigadas. O presente estudo teve como objetivo investigar se o enriquecimento ambiental promove alteração do comportamento emocional, da sensibilidade nociceptiva, bem como na imunorreatividade à nNOS no núcleo central da amígdala, na formação hipocampal e na região dorsolateral da substância cinzenta periaquedutal, em ratos submetidos ao estresse por isolamento social ou estresse crônico variado e mantidos em ambiente enriquecido ou sem enriquecimento. Ratos machos Wistar (~70g) foram divididos aleatoriamente em dois grandes grupos experimentais: Ambiente Padrão (Padrão) ou Ambiente Enriquecido (EE), mantidos por 38 dias. Cada grupo foi subdividido dependendo do tipo de estresse crônico: Controle (sem estresse), Isolamento Social (por 38 dias) e Estresse Crônico Variado (do dia 28 ao dia 37). Ao fim do tempo experimental (dia 38) os ratos foram avaliados quanto ao comportamento emocional pelos testes de labirinto em cruz elevado (LCE) e claro/escuro (TCE) e sensibilidade nociceptiva pelo teste da placa quente (a qual foi realizada em duas etapas, sendo a primeira medida no dia 0 e outra no dia 38). A eutanásia dos ratos ocorreu no dia 39, para coleta do encéfalo para análise da imunorreatividade à óxido nítrico sintase neuronal (nNOS). Levando-se em consideração o comportamento emocional e a sensibilidade nociceptiva, os diferentes tipos de estresse crônico diminuíram a porcentagem de tempo, a frequência de entrada e a exploração da extremidade dos braços abertos e na frequência de mergulho de cabeça no teste do LCE, apesar de não alterar a sensibilidade nociceptiva. Por outro lado, o enriquecimento ambiental aumentou a porcentagem de tempo, a frequência de entrada e a exploração da extremidade dos braços abertos no teste do LCE, apesar de não alterar a sensibilidade nociceptiva. Foi observado aumento da imunorreatividade à nNOS na formação hipocampal em diferentes tipos de estresse crônico. Em particular, na região de CA3 houve interação significante entre os fatores estresse por isolamento social e ambiente de manutenção. Deste modo, os resultados obtidos neste trabalho sugerem que a formação hipocampal desempenha importante função no efeito ansiogênico exercido pelos diferentes tipos de estressores crônicos (aqui representados pelo isolamento social e pelo estresse crônico variado) provavelmente pela ativação do sistema nitrérgico e sugere-se que o enriquecimento possa prevenir o comportamento do tipo ansioso. / Adaptive responses to stress may be accompanied by changes in emotional behaviors, in particular related to fear and anxiety, as well as changes in pain sensitivity. Furthermore, the role of nitric oxide in brain areas related to defensive behavior has been investigated. Although several evidences have shown that environmental enrichment improves memory processes, learning and nociceptive responses, the relationship between chronic stress and the advantages of using environmental enrichment is still poorly investigated. The present study aimed to investigate whether environmental enrichment promotes alteration of the emotional behavior, nociceptive sensitivity, as well as immunoreactivity to neuronal nitric oxide synthase (nNOS) in the central nucleus of the amygdala, hippocampal formation and dorsolateral periaqueductal gray matter in rats submitted to social isolation stress or chronic unpredictable stress and reared in enriched environment or standard environment. Male Wistar rats (~ 70g) were randomly divided into two major experimental groups: Standard Environment (Standard) or Enriched Environment (EE), maintained for 38 days. Each group was subdivided according to the type of chronic stress: Control (without stress), Social Isolation (for 38 days) and Chronic Unpredictable Stress (from day 28 to day 37). At the end of the experimental time (day 38), the rats were evaluated for emotional behavior by elevated plus maze (EPM) and light/dark box (LDBT) tests and nociceptive sensitivity by the hot plate test (which was performed in two steps , the first being measured on day 0 and the other on day 38). Euthanasia of rats occurred on day 39, to collect the brain for nNOS immunoreactivity analysis. Taking into account emotional behavior and nociceptive sensitivity, the different types of chronic stress decreased the percentage of time, the frequency of entry of the open arms, end-arm exploration and the head dipping frequency in the EPM, despite of not altering the nociceptive sensitivity. On the other hand, environmental enrichment increased the percentage of time, the frequency of entry of the open arms and the end arm-exploration in the EPM test, although it did not alter the nociceptive sensitivity. Increased immunoreactivity to nNOS in hippocampal formation was observed in different types of chronic stress. In particular, in the CA3 region there was a significant interaction between stress factors due to social isolation and maintenance environment. Thus, the results obtained in this study suggest that hippocampal formation plays an important role in the anxiogenic effect exerted by the different types of chronic stressors (represented here by social isolation and by chronic chronic stress) probably due to the activation of the nitrergic system and it is suggested that environmental enrichment can prevent of anxiety-like behavior.

O estresse crônico ou agudo pode alterar diversas funções relacionadas ao sistema cardiovascular, ocasionando doenças cardíacas. O sistema renina-angiotensina (SRA), importante participante do controle dessas funções, é profundamente afetado em resposta ao estresse. A angiotensina II (Ang II) é reconhecida como hormônio multifuncional que influencia diversos processos celulares importantes para a regulação da função vascular, incluindo regulação do tônus vascular, crescimento celular, dentre outros. Outro componente do SRA é a angiotensina 1-7 (Ang 1-7), suas ações vasculares envolvem aumento na produção de prostanóides vasodilatadores, óxido nítrico e fator hiperpolarizante derivado do endotélio. O objetivo do presente trabalho foi avaliar as conseqüências do estresse, agudo ou crônico, sobre as atividades vasomotoras da Ang II e da Ang 1-7, os mecanismos envolvidos na contração e relaxamento induzidos, respectivamente, por estes peptídeos e as modificações na expressão dos receptores AT1, AT2 e Mas, em carótida de ratos. O estresse crônico levou à diminuição do ganho de peso corpóreo dos animais, promoveu remodelamento das artérias carótidas, com significativo aumento da camada média acompanhada de redução da resposta de relaxamento da Ang 1-7, embora a expressão de seus receptores, do tipo Mas, estivesse aumentada. A maior expressão de receptores de Ang II, AT1 e AT2, desencadeada pelo estresse agudo não alterou a resposta contrátil deste peptídeo. Em carótidas de animais submetidos ao estresse crônico observa-se redução do Emax da Ang II e da Ang 1-7 após incubação com indometacina, sugerindo que prostanóides estão envolvidos na resposta vascular tanto da Ang II quanto da Ang 1-7 em situações de exposição prolongada ao estresse. A maior expressão de nitrotirosina em carótidas de animais expostos tanto ao estresse agudo quanto crônico, demonstra que o óxido nítrico e estresse oxidativo parecem estar relacionados às alterações vasomotoras, em resposta aos peptídeos Ang II e Ang 1-7. Foi evidenciado que o estresse agudo eleva significativamente os níveis plasmáticos de corticosterona e a produção de espécies reativas de oxigênio (EROs). Estes dados sugerem que os estresses agudo e crônico, por imobilização, alteram a expressão de receptores do SRA e a vasoatividade de carótidas em resposta à Ang II e Ang 1-7 em função de diferentes mecanismos celulares. / The chronic or acute stress can alter various functions of the cardiovascular system, causing heart disease. The renin-angiotensin system (RAS), a major participant in control of these functions, is profoundly affected in response to stress. Angiotensin II (Ang II) is recognized as a multifunctional hormone that influences many cellular processes important for the regulation of vascular function, including regulation of vascular tone, cell growth, among others. Another component of the RAS is angiotensin 1-7 (Ang 1-7), their actions involve an increase in vascular production of prostanoid vasodilators, nitric oxide and endothelium-derived hyperpolarizing factor. The aim of this study was to evaluate the consequences of chronic or acute stress on vasomotor activity of Ang II and Ang 1-7, the mechanisms involved in contraction and relaxation induced, respectively, by these peptides and the changes in the expression of AT1, AT2 and Mas in rat carotid artery. Chronic stress has led to decreased body weight gain of animals, promoted remodeling of carotid arteries with a significant increase in the medial layer accompanied by a reduction of the relaxation response to Ang 1-7, although the expression of their receptors (Mas) was increased. The highest expression of Ang II receptors, AT1 and AT2, triggered by acute stress did not alter the contractile response of this peptide. In carotid arteries of animals subjected to chronic stress is observed reduction of Emax of Ang II and Ang 1-7 after incubation with indomethacin, suggesting that prostanoids are involved in the vascular response of both Ang II and Ang 1-7 in exposed situations prolonged stress. The greater expression of nitrotyrosine in carotids from animals exposed to both acute or chronic stress, demonstrates that nitric oxide and oxidative stress appear to be related to vasomotor changes in response to peptides Ang II and Ang 1-7. It was shown that acute stress increases plasma levels of corticosterone and the production of reactive oxygen species (ROS). These data suggest that acute and chronic stress by immobilization, alter the expression of receptors of RAS and vasomotor activity in carotid artery in response to Ang II and Ang 1-7 by different cellular mechanisms.

O gás monóxido de carbono (CO) possui diversas funções no sistema nervoso central (SNC) funcionando como neuromodulador, como por exemplo da regulação da temperatura corporal, da nocicepção e mais recentemente, do comportamento emocional. Este neuromodulador gasoso é produzido pela ação da enzima heme oxigenase (HO), a qual é encontrada em diferentes áreas do SNC. Com destaque, esta enzima tem alta expressão no locus coeruleus (LC), o que sugere o envolvimento do CO na modulação de funções desempenhadas por esta estrutura. O LC localiza-se na ponte, sendo a maior origem da inervação noradrenérgica do SNC. Esta estrutura tem participação ativa na modulação das respostas relacionadas ao estresse, em particular, na modulação do comportamento emocional, desde que integra o Sistema de Inibição Comportamental (SIC), o qual inclui ainda o sistema septo-hipocampal e os núcleos da rafe. O SIC é responsável por comandar respostas defensivas de avaliação de risco, alerta e atenção, as quais podem ser eliciadas pela ansiedade. Dentro desta perspectiva, o presente estudo teve como objetivo avaliar se a ativação sistêmica da via HO-CO pode modular o comportamento emocional de ratos, e se há participação do LC. Assim, este trabalho avaliou se o tratamento sistêmico via intraperitoneal (i.p.) agudo (3 h antes) ou crônico (10 dias/2 vezes ao dia) com um liberador de monóxido de carbono (CORM-2), ou com indutor da enzima HO (CoPP), altera as respostas comportamentais no teste do labirinto em cruz elevado (LCE) e no teste claro-escuro (TCE) em ratos, bem como a expressão da enzima HO no LC. Em uma segunda etapa foi avaliado se a administração aguda de CORM-2 ou CoPP altera o comportamento avaliado no LCE e no TCE de ratos submetidos ao estresse crônico variado (ECV) por 10 dias. Os resultados mostraram que o CO induzido pela administração aguda ou crônica de CORM-2 ou CoPP possui efeito ansiolítico. Ainda, o tratamento com CORM-2 ou CoPP aumentou a expressão da enzima HO-1 em células localizadas no LC, sem alterar a imunorreatividade à enzima HO-2. Considerando os grupos submetidos ao estresse ECV, nem a ativação da via HO-CO ou o ECV apresentaram efeitos significativos nos comportamentos avaliados nos testes LCE e TCE. Os resultados do presente estudo sugerem que o tratamento sistêmico com drogas que modulam a liberação de CO possui claro efeito ansiolítico. Assim, é possível que o CO possa ser uma droga com potencial terapêutico para o tratamento de desordens neuropsiquiátricas. / The carbon monoxide gas (CO) has several functions in the central nervous system acting as a neuromodulator, such as in the body temperature regulation, nociception and more recently, in the emotional behavior modulation. This gas is produced by the action of the heme oxigenase enzyme (HO), which is found in different areas of the central nervous system (CNS). It is important to note that this enzyme has high expression in the locus coeruleus (LC), suggesting the involvement of CO in the modulation functions performed by this midbrain structure. LC is located in the pons, being the source of majority of the noradrenergic innervation of the CNS. This structure is intimately involved in the stress modulation responses, particularly in the emotional behavior regulation, since it integrates the Behavioral Inhibition System (BIS), which also includes septum-hippocampal system and raphe nucleus. The BIS is responsible for defensive responses like the risk assessment and alertness trigged by anxiety. Within this perspective, the present study was designed to evaluate whether the systemic HO-CO pathway can modulate emotional behavior of rats, and if the HO enzyme of the neurons located into LC is involved in this response. Thus, this study evaluated whether the acute systemic i.p. treatment (3 hours before) or chronic (10 days / 2 times a day) with a carbon monoxide releaser (CORM-2) or inducer of heme enzyme oxygenase (CoPP), is able to alter the behavioral responses in the elevated plus maze (EPM) and in the light-dark box test (LDB) in rats, and the HO enzyme expression in the LC. Furthermore, the effect of the acute administration of CORM-2 or CoPP was evaluated in the emotional behavior assessed in the EPM and LDB by rats submitted to unpredictable chronic stress (during 10 days). The results showed that the CO induced by acute or chronic administration of CORM-2 or CoPP has an anxiolytic-like effect. Furthermore, treatment with CORM-2 or CoPP promoted an increase of HO-1 enzyme expression in cells located in the LC without altering the immunoreactivity of HO-2 enzyme. Still, considering the rats subjected to stress UCS neither the activation of HO-CO pathway nor the UCS protocol altered the emotional behavior evaluated in the EPM and LDB tests. The results of this study suggest that systemic treatment with drugs that modulate the CO release has anxiolytic effect. Thus, it is possible that CO can be a potential drug therapeutic target for neuropsychiatric disorders.

Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2017-10-09T19:14:17Z No. of bitstreams: 1 MARIA EDUARDA DE LIMA.pdf: 3141919 bytes, checksum: f33f081cbf3931d572940d623c8c2074 (MD5) / Approved for entry into archive by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2017-10-09T19:14:51Z (GMT) No. of bitstreams: 1 MARIA EDUARDA DE LIMA.pdf: 3141919 bytes, checksum: f33f081cbf3931d572940d623c8c2074 (MD5) / Made available in DSpace on 2017-10-09T19:14:52Z (GMT). No. of bitstreams: 1 MARIA EDUARDA DE LIMA.pdf: 3141919 bytes, checksum: f33f081cbf3931d572940d623c8c2074 (MD5) Previous issue date: 2017-08-04 / A erva mate é o produto do processamento de folhas secas e moídas de uma espécie arbórea, conhecida como Ilex paraguariensis. A apresentação comercial da erva-mate é utilizada no preparo de uma bebida tradicional, muito consumida na América do Sul. Dados da literatura tem comprovado uma diversidade de efeitos benéficos da erva-mate, principalmente o antioxidante. Sabe-se que uma grande quantidade de patologias apresenta o estresse oxidativo como um dos seus mecanismos nocivos, desta maneira, a busca por compostos naturais que possam balancear tais situações foi intensificada nos últimos anos. Considerando os aspectos mencionados, o objetivo principal do presente estudo foi avaliar os possíveis efeitos protetores do extrato de Ilex paraguariensis em diferentes perspectivas com ênfase no estresse oxidativo. Inicialmente, foi realizada a caraterização do extrato por HPLC, seguido por uma comparação in vitro em sinaptossomas, do extrato (200 mg/mL) com o seu composto majoritário, ácido clorogênico CGA (2 mg/mL), quanto a produção de ROS, peroxidação de lipídios, função mitocondrial por MTT e a razão GSH/GSSG. Por conseguinte, foi realizada a avaliação in vivo, onde ratos Wistar machos (300-330 g) foram submetidos a estresse por restrição de movimentos, associado a outros estímulos estressantes, por 21 dias, 6h por dia (crônico) e tratados, por via oral, concomitantemente com extrato (200 mg/mL) ou CGA (2 mg/mL) e foram analisados parâmetros comportamentais de atividade locomotora e ansiedade, bem como, aspectos de dano celular, em córtex, hipocampo e estriado. Por fim, em um modelo de camundongos diabéticos, induzido com estreptozotocina (100 mg/kg), foram verificados os efeitos do extrato de erva mate (850 mg/kg), por via oral, sobre os níveis de glicose, neuropatia diabética e marcadores de estresse oxidativo, em rim, fígado e cérebro. O extrato de erva mate mostrou-se mais efetivo que o ácido clorogênico na proteção do dano oxidativo em sinaptossomas, reduzindo a formação de ROS, peroxidação de lipídios e depleção de glutationa, fatos que podem explicar o efeito do extrato em prevenir a disfunção mitocondrial avaliada. Da mesma maneira, no modelo de estresse por restrição de movimentos, o extrato de erva mate foi mais efetivo que o ácido clorogênico em prevenir as alterações comportamentais dos animais. O grupo que recebeu o extrato como tratamento, apresentou atividade locomotora igual ou superior a do grupo controle. Os animais tratados com extrato também se mostraram menos ansiosos que os do grupo estressado que não recebeu tratamento. Além disso, o extrato exibiu efeito de proteção do dano celular de córtex, hipocampo e estriado, pois os animais tratados apresentaram um maior número de células viáveis nesses tecidos. Com relação aos efeitos do extrato no modelo induzido de diabetes, verificou-se que a erva mate possui atividade de proteção ao estresse oxidativo envolvido na patogênese dessa patologia, além de reduzir de maneira significativa o nível glicêmico dos animais e apresentar efeito protetor à neuropatia diabética. Com base nos resultados encontrados, é possível dizer que, de modo geral, a erva mate atua na proteção de diferentes aspectos do estresse oxidativo devido ao sinergismo dos seus componentes, tendo em vista que o ácido clorogênico isolado não apresentou efeito protetor igual ou superior ao do extrato. Através do seu efeito antioxidante, apresenta benefícios à redução dos danos causados pela hiperglicemia crônica no diabetes mellitus e também, na modulação de efeitos neuroprotetores e função mitocondrial. / Yerba mate is the product of the processing of dried and ground leaves of a tree species, known as Ilex paraguariensis. The commercial presentation of yerba mate is used in the preparation of a traditional drink, widely consumed in South America. Data from the literature has proven a variety of beneficial effects of yerba mate, especially the antioxidant. It is known that a great number of pathologies present oxidative stress as one of its harmful mechanisms, in this way, the search for natural compounds that can balance such situations has intensified in recent years. Considering the mentioned aspects, the main objective of the present study was evaluate the possible protective effects of Ilex paraguariensis extract in different perspectives with emphasis on oxidative stress. Initially, was made the characterization of HPLC extract, followed by an in vitro comparison in synaptosomes, of the extract (200 mg / mL) with its major compound, chlorogenic acid CGA (2 mg / mL) in ROS formation, lipid peroxidation, mitochondrial function by MTT and the GSH / GSSG ratio. Therefore, in vivo evaluation was performed, where male Wistar rats (300-330 g) underwent movement restriction stress associated with other stress stimuli for 21 days, 6 hours per day (chronic) and treated with extract (200 mg / mL) or CGA (2 mg / mL) and behavioral parameters of locomotor activity and anxiety were analyzed, as well as aspects of cellular damage in the cortex, hippocampus and striatum. Finally, in a model of diabetic mice, induced with streptozotocin (100 mg / kg), were verified the effects of yerba mate extract (850 mg / kg) on glucose levels, diabetic neuropathy and markers Of oxidative stress, in kidney, liver and brain. The yerba mate extract was shown to be more effective than chlorogenic acid in the protection of oxidative damage in synaptosomes, by reducing ROS formation, lipid peroxidation and glutathione depletion, which may explain the effect of the extract in preventing mitochondrial dysfunction evaluated. Likewise, in the model of stress by restriction of movement, the extract of mate grass was more effective than the chlorogenic acid in preventing the behavioral alterations of the animals. The group that received extract as treatment had locomotor activity equal to or greater than the control group. The animals treated with extracts were also less anxious than those of the stressed group that did not receive treatment. In addition, the extract exhibited a protective effect on cell damage in cortex, hippocampal and striatum, as treated animals had a higher number of viable cells in these tissues. Regarding the effects of the extract in the induced model of diabetes, it was verified that the yerba mate has activity of protection to the oxidative stress involved in the pathogenesis of this pathology, in addition to significantly reduce the glycemic level of the animals and present protective effect to diabetic neuropathy. Based on the results found, it is possible to say that, in general, yerba mate acts in the protection of different aspects of oxidative stress due to the synergism of its components, considering that the isolated chlorogenic acid did not present a protective effect equal or greater than of the extract. Through its antioxidant effect, present benefits in reducing the damage caused by chronic hyperglycemia in diabetes mellitus, in the modulation of neuroprotective effects and mitochondrial function.

Respostas adaptativas ao estresse podem ser acompanhadas por alterações nos comportamentos emocionais, em particular relacionados com medo e ansiedade, bem como alterações na sensibilidade dolorosa. Ainda, tem sido investigado o papel do óxido nítrico em áreas encefálicas relacionadas ao comportamento defensivo. Embora várias evidências têm demonstrado que o enriquecimento ambiental promove melhora nos processos de memória, no aprendizado e em respostas nociceptivas, a relação entre o estresse crônico e as vantagens da utilização do enriquecimento ambiental ainda são pouco investigadas. O presente estudo teve como objetivo investigar se o enriquecimento ambiental promove alteração do comportamento emocional, da sensibilidade nociceptiva, bem como na imunorreatividade à nNOS no núcleo central da amígdala, na formação hipocampal e na região dorsolateral da substância cinzenta periaquedutal, em ratos submetidos ao estresse por isolamento social ou estresse crônico variado e mantidos em ambiente enriquecido ou sem enriquecimento. Ratos machos Wistar (~70g) foram divididos aleatoriamente em dois grandes grupos experimentais: Ambiente Padrão (Padrão) ou Ambiente Enriquecido (EE), mantidos por 38 dias. Cada grupo foi subdividido dependendo do tipo de estresse crônico: Controle (sem estresse), Isolamento Social (por 38 dias) e Estresse Crônico Variado (do dia 28 ao dia 37). Ao fim do tempo experimental (dia 38) os ratos foram avaliados quanto ao comportamento emocional pelos testes de labirinto em cruz elevado (LCE) e claro/escuro (TCE) e sensibilidade nociceptiva pelo teste da placa quente (a qual foi realizada em duas etapas, sendo a primeira medida no dia 0 e outra no dia 38). A eutanásia dos ratos ocorreu no dia 39, para coleta do encéfalo para análise da imunorreatividade à óxido nítrico sintase neuronal (nNOS). Levando-se em consideração o comportamento emocional e a sensibilidade nociceptiva, os diferentes tipos de estresse crônico diminuíram a porcentagem de tempo, a frequência de entrada e a exploração da extremidade dos braços abertos e na frequência de mergulho de cabeça no teste do LCE, apesar de não alterar a sensibilidade nociceptiva. Por outro lado, o enriquecimento ambiental aumentou a porcentagem de tempo, a frequência de entrada e a exploração da extremidade dos braços abertos no teste do LCE, apesar de não alterar a sensibilidade nociceptiva. Foi observado aumento da imunorreatividade à nNOS na formação hipocampal em diferentes tipos de estresse crônico. Em particular, na região de CA3 houve interação significante entre os fatores estresse por isolamento social e ambiente de manutenção. Deste modo, os resultados obtidos neste trabalho sugerem que a formação hipocampal desempenha importante função no efeito ansiogênico exercido pelos diferentes tipos de estressores crônicos (aqui representados pelo isolamento social e pelo estresse crônico variado) provavelmente pela ativação do sistema nitrérgico e sugere-se que o enriquecimento possa prevenir o comportamento do tipo ansioso. / Adaptive responses to stress may be accompanied by changes in emotional behaviors, in particular related to fear and anxiety, as well as changes in pain sensitivity. Furthermore, the role of nitric oxide in brain areas related to defensive behavior has been investigated. Although several evidences have shown that environmental enrichment improves memory processes, learning and nociceptive responses, the relationship between chronic stress and the advantages of using environmental enrichment is still poorly investigated. The present study aimed to investigate whether environmental enrichment promotes alteration of the emotional behavior, nociceptive sensitivity, as well as immunoreactivity to neuronal nitric oxide synthase (nNOS) in the central nucleus of the amygdala, hippocampal formation and dorsolateral periaqueductal gray matter in rats submitted to social isolation stress or chronic unpredictable stress and reared in enriched environment or standard environment. Male Wistar rats (~ 70g) were randomly divided into two major experimental groups: Standard Environment (Standard) or Enriched Environment (EE), maintained for 38 days. Each group was subdivided according to the type of chronic stress: Control (without stress), Social Isolation (for 38 days) and Chronic Unpredictable Stress (from day 28 to day 37). At the end of the experimental time (day 38), the rats were evaluated for emotional behavior by elevated plus maze (EPM) and light/dark box (LDBT) tests and nociceptive sensitivity by the hot plate test (which was performed in two steps , the first being measured on day 0 and the other on day 38). Euthanasia of rats occurred on day 39, to collect the brain for nNOS immunoreactivity analysis. Taking into account emotional behavior and nociceptive sensitivity, the different types of chronic stress decreased the percentage of time, the frequency of entry of the open arms, end-arm exploration and the head dipping frequency in the EPM, despite of not altering the nociceptive sensitivity. On the other hand, environmental enrichment increased the percentage of time, the frequency of entry of the open arms and the end arm-exploration in the EPM test, although it did not alter the nociceptive sensitivity. Increased immunoreactivity to nNOS in hippocampal formation was observed in different types of chronic stress. In particular, in the CA3 region there was a significant interaction between stress factors due to social isolation and maintenance environment. Thus, the results obtained in this study suggest that hippocampal formation plays an important role in the anxiogenic effect exerted by the different types of chronic stressors (represented here by social isolation and by chronic chronic stress) probably due to the activation of the nitrergic system and it is suggested that environmental enrichment can prevent of anxiety-like behavior.

Thesis (Ph.D. (Electronical Engineering))--North-West University, Potchefstroom Campus, 2008.

Summary: Salivary alpha-amylase: More than an enzyme - Investigating confounders of stress-induced and basal amylase activity (Dipl.-Psych. Jana Strahler) The hypothalamus-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) are two of the major systems playing a role in the adaptation of organisms to developmental changes that threaten homeostasis. The HPA system involves the secretion of glucocorticoids, including cortisol, into the circulatory system. Numerous studies have been published that introduced salivary cortisol to assess HPA axis activity and therefore strengthens its role as an easy obtainable biomarker in stress research that can be monitored easily and frequently. Recent findings suggest a possible surrogate marker of autonomic activity due to autonomic innervation of salivary glands: salivary alpha-amylase (sAA). Up to date, additional methodological research is needed for a better understanding of the advantages and disadvantages of sAA activity in comparison to already established markers of ANS activity. The aim of the present thesis is to further our knowledge of confounders of sAA activity under basal and acute stress conditions and to strengthen the validity of this enzyme as an easy obtainable alternative for ANS testing. After introducing classical and modern stress concepts and stress system physiology (chapter 2), the reader is acquainted with anatomical basics of salivary gland innervation and secretion of salivary proteins, including sAA, due to autonomic innervation (chapter 3 and 4). Afterwards, a more nuanced review of methodological considerations of sAA determination shows gaps of knowledge concerning its usefulness as a marker of ANS activity (chapter 5). Given the fact that the integration of sAA into developmental and aging research is a relative recent phenomenon, several issues have to be addressed before a final conclusion could be drawn. Therefore, we conducted a series of studies incorporating these considerations regarding behavioral correlates of inter- and intraindividual differences in sAA activity with a special emphasis on older adults. Chapter 7 deals with sAA activity under psychological stress conditions in different age groups. Since vulnerability to disease and disease prevalence patterns change with age, it is important to investigate stress reactivity of people in different age groups. We therefore investigated children between 6 and 10 years, because childhood is a sensitive period of growth and development, and thus plays an important role for later life health. Young adults were included to represent the most studied human age group as a reference. Older adults between 59 and 61 years were investigated, because at this age the course is set for the further development of a person’s health in later life, and because autonomic stress responses in older age might be important determinants of cardiovascular and inflammatory aging. Our goal is to test for associations of sAA with more established stress system markers, i.e., salivary cortisol as outcome measurement of HPA reactivity, heart rate (HR) and heart rate variability (HRV) as markers for autonomic reactivity, and to directly compare these responses between different age groups across the life span. Secretion of sAA and cortisol was repeatedly assessed in 62 children, 78 young adults, and 74 older adults after exposure to a standardized psychosocial stressor, the Trier Social Stress Test. In addition, cardiovascular activity was measured in both adult groups. Older adults showed attenuated sAA, HR, and HRV responses. Furthermore, we found higher sAA but lower cortisol at baseline as well as lower sAA and cortisol responses in children. Age by sex interactions were observed only for cortisol with higher responses in older male participants. No associations between the parameters were found. Results in children and young adults confirm previous results. Overall, findings implicate sAA as an alternative or additional autonomic stress marker throughout the life span, with marked and rapid responsiveness to stress in three relevant age groups. The impact of age and chronic stress on basal sAA activity is the center of interest in chapter 8. We therefore assessed diurnal profiles of sAA and salivary cortisol in 27 younger and 31 older competitive ballroom dancers as well as 26 younger and 33 older age- and sex-matched controls. According to the Allostatic Load concept, repeated, non-habituating responses to social-evaluative conditions, which characterize the lives of competitive ballroom dancers, should be associated with stress system dysregulations. Furthermore, we expect to see an increased sympathetic drive associated higher overall alpha-amylase activity in older adults. Analyses revealed an elevated daily overall output of sAA in older adults while there was no effect of age on mean cortisol levels. Alterations of diurnal rhythms were only seen in younger male dancers showing a flattened diurnal profile of sAA and younger dancers and female older dancers showing a blunted diurnal rhythmicity of cortisol. Furthermore, we found a negative correlation between summary indices of basal sAA and the amount of physical activity. In conclusion, higher overall output of sAA in older adults was in line with the phenomenon of a “sympathetic overdrive” with increasing age. Furthermore, a lower output of sAA in people who are more physical active was in line with the hypothesis of an exercise-induced decrease of sympathetic activity. Taken together, results of chapter 7 and 8 show a clear impact of age on sAA activity, either under acute stress or basal conditions. One problem when integrating sAA into developmental and aging research is the use of adrenergic agonists and antagonists what is very common in older adults, i.e. antihypertensive drugs (AD). As well, the previously shown sympathetic overactivity that occurs with normal aging is associated with higher blood pressure (BP). Therefore, chapter 9 deals with a possible impact of high BP and AD on diurnal sAA activity in 79 older adults (33 normotensive adults, 16 medicated vs. 45 hypertensive adults, 34 medicated). Results showed a pronounced rhythm of sAA in all groups. Diurnal profiles differed significantly between men and women with men lacking the typical decrease of sAA in the morning and showing more pronounced alterations throughout the day. An effect of AD on sAA profiles and area under the curve values indicates that subjects not using AD´s show a heightened diurnal profile and a higher total output of sAA. Descriptively, this was also true for hypertensive older adults. Hypertensive subjects and those not using AD showed the highest diurnal output of sAA and the steepest slope. In sum, our results show an impact of antihypertensive medication and a difference between normotensive and hypertensive subjects on characteristics of diurnal sAA activity. Hence, findings are of particular interest in research using sAA as a prognostic indicator of pathological states and processes. Given the fact that hypertension was also shown to be associated with substantial changes of transmitters within the suprachiasmatic nucleus (SCN) - the “biological clock” that receives photic input from retinal glands via the retinohypothalamic pathway - and an altered output from the SCN to the sympathetic nervous system, we broaden the idea of a possible effect of different lighting conditions on morning sAA profiles in chapter 10. In a counterbalanced within-subjects design six men and 16 women of different ages collected sAA morning profiles on two consecutive days with leaving their shutters closed on the one day (= dark) and open their shutters on the other day (= bright). We were able to replicate earlier findings of light-induced changes of salivary cortisol with higher responses during the bright condition. On either day, women showed larger cortisol increases than men. Despite multisynaptic autonomic connections arising from the SCN projecting to multiple organs of the body, we could not find an effect of sunlight on sAA morning profiles. Evidence for circadian clock gene expression in human oral mucosa might account for this result and indicates that peripheral oscillators may act more like integrators of multiple different time cues, e.g. light, food intake, instead of a “master” oscillator (SCN). Results of chapter 7 to 10 provide clear evidence that sAA is heightened in states of autonomic arousal, i.e. stress, aging and hypertension, and that its circadian rhythmicity seems to be regulated rather integrative than directly via efferent input from hypothalamic SCN neurons. In chapter 11 this thesis tries to approach one central question: What is the biological meaning of the findings made? According to this enzyme´s anti-bacterial and digestive action short term changes might not have a biological meaning itself but rather reflect just a small part of multiple coordinated body responses to stressful stimuli. While the sympathetic branch of the ANS mainly stimulates protein secretion, the parasympathetic branch stimulates saliva flow. Acute stress responses might therefore be interpreted as reflecting predominant sympathetic activity together with parasympathetic withdrawal. The same mechanism could also be suitable for the finding of higher diurnal levels of sAA in older adults or hypertensive subjects reflecting a higher peripheral sympathetic tone in these groups. Diurnal profiles of sAA itself may reflect circadian changes in autonomic balance. Circadian rhythms are of great advantage since they enable individuals to anticipate. This pre-adaptation enables the individual to cope with upcoming demands and challenges. Our finding of a relationship between sAA and salivary cortisol what strengthens the relevance of glucocorticoids that were previously shown to be able to phase shift circadian rhythms in cells and tissue. Within a food-related context there is evidence that decreasing levels of sAA in the morning could reflect increases of feeling hungry since sAA systematically increases during food consumption and with the subjective state of satiety. So far, much more research is needed to identify underlying physiological mechanisms of circadian sAA rhythmicity. Taking the next step, future studies will have to focus on the integration of sAA assessment into longitudinal studies and different disease states to prove its applicability as a marker of sympathetic neural functioning in the genesis and prognosis of disease.

The rapid growth of biotechnology has promoted industries to harness the market in the field of human energy systems. A growing literature of research has linked human energy systems to weight loss, major diseases or illnesses. In our modern society, the general public is exposed to everyday stress, which often results in the development of chronic stress. Therefore, stress becomes an important area of medicine. It has been postulated that suppressing these physiological responses may help in disease prevention. Consequently, there is an urge for defining a model integrating stress with the human energy model. Over the past decades, a large amount of research has been put forward in defining the physiological responses or changes when an individual experiences psychological or environmental changes such as interpersonal dysfunction, traumatic experiences and diseases. Interestingly, it reveals that blood glucose fluctuation tends to be the end product of most psychological or physiological stressors. The blood glucose system is one of the major subsystems of the complete metabolic fuel system in humans. In this study, an empirical model and procedure for the derivation of the model due to various psychological influences on the human energy system are presented. This study can be divided into two main sections. An overview of a previously developed unit (ets: equivalent teaspoon sugar) for blood glucose quantification is given in the first section. Stress quantification methods are derived in the second section and a link between these methods and ets is drawn. A verification study of the derived model is also presented in the second section. Stress can be divided into physiological stress and psychological stress. Between the two types of stress, a generalised model based on studies of physiological stress has been drawn and accepted by the public. However, the generalised model does not account for psychological stress. Evidence shows that depending on the specific nature of a stressful circumstance, it can cause different activations of central circuits leading to the release of different neurotransmitters. However, these neurotransmitters have a common effect of increasing blood glucose concentrations. A substantial amount of literature shows that, when stress involves mental effort, epinephrine (EPI) is the main endocrine response. However, stress that does not require mental effort mainly induces cortisol release. The response models for different types of stress were derived using these relations. Furthermore, it is known that prolonged stress may lead to the development of disease. Several studies have used this observation and associated chronic stress with the relative risk factor of cardiovascular disease (CVD). Previously, different quartiles of risk factors for CVD have been related to blood glucose energy and ets expenditure. This link was further utilised to quantify chronic stress in this study. Increases in either of the two endocrine concentrations have been shown to raise the blood glucose level. In order to demonstrate the benefits of applying the ets concept, the cortisol and epinephrine responses were further quantified using the new glucose quantification method, the equivalent teaspoon sugar (ets) concept. The models derived in this study were verified against measured data. The models reveal a strong agreement with the measured data and therefore support the feasibility of these quantification methods. In conclusion, a link does exist between blood glucose energy and stress, and the highly accurate models derived for this association may serve as an adjunct tool for glycaemic control and stress management. / Thesis (Ph.D. (Electronical Engineering))--North-West University, Potchefstroom Campus, 2008.

The rapid growth of biotechnology has promoted industries to harness the market in the field of human energy systems. A growing literature of research has linked human energy systems to weight loss, major diseases or illnesses. In our modern society, the general public is exposed to everyday stress, which often results in the development of chronic stress. Therefore, stress becomes an important area of medicine. It has been postulated that suppressing these physiological responses may help in disease prevention. Consequently, there is an urge for defining a model integrating stress with the human energy model. Over the past decades, a large amount of research has been put forward in defining the physiological responses or changes when an individual experiences psychological or environmental changes such as interpersonal dysfunction, traumatic experiences and diseases. Interestingly, it reveals that blood glucose fluctuation tends to be the end product of most psychological or physiological stressors. The blood glucose system is one of the major subsystems of the complete metabolic fuel system in humans. In this study, an empirical model and procedure for the derivation of the model due to various psychological influences on the human energy system are presented. This study can be divided into two main sections. An overview of a previously developed unit (ets: equivalent teaspoon sugar) for blood glucose quantification is given in the first section. Stress quantification methods are derived in the second section and a link between these methods and ets is drawn. A verification study of the derived model is also presented in the second section. Stress can be divided into physiological stress and psychological stress. Between the two types of stress, a generalised model based on studies of physiological stress has been drawn and accepted by the public. However, the generalised model does not account for psychological stress. Evidence shows that depending on the specific nature of a stressful circumstance, it can cause different activations of central circuits leading to the release of different neurotransmitters. However, these neurotransmitters have a common effect of increasing blood glucose concentrations. A substantial amount of literature shows that, when stress involves mental effort, epinephrine (EPI) is the main endocrine response. However, stress that does not require mental effort mainly induces cortisol release. The response models for different types of stress were derived using these relations. Furthermore, it is known that prolonged stress may lead to the development of disease. Several studies have used this observation and associated chronic stress with the relative risk factor of cardiovascular disease (CVD). Previously, different quartiles of risk factors for CVD have been related to blood glucose energy and ets expenditure. This link was further utilised to quantify chronic stress in this study. Increases in either of the two endocrine concentrations have been shown to raise the blood glucose level. In order to demonstrate the benefits of applying the ets concept, the cortisol and epinephrine responses were further quantified using the new glucose quantification method, the equivalent teaspoon sugar (ets) concept. The models derived in this study were verified against measured data. The models reveal a strong agreement with the measured data and therefore support the feasibility of these quantification methods. In conclusion, a link does exist between blood glucose energy and stress, and the highly accurate models derived for this association may serve as an adjunct tool for glycaemic control and stress management. / Thesis (Ph.D. (Electronical Engineering))--North-West University, Potchefstroom Campus, 2008.

Premenstrual depressive symptoms and mood swings affect 3-8% of women in fertile age. The female hormones are believed to be the cause. Progesterone is well studied, but estrogen is not, and either are other causes such as intimate partner violence and chronic stress. The aim in this thesis was to investigate the influence of hormones as well as psychological aspects on the most common problems among women seeking care for premenstrual symptoms. In a cross-sectional study, four groups of women were included: ongoing users of oral contraceptives, with or without adverse mood symptoms and previous users, with or without experience of adverse mood. Depression and anxiety were significantly more common in both groups with reported adverse mood, in comparison with their control groups with no adverse mood. Self-reported PMS was significantly more common in those women who reported adverse mood, however, there was no difference in prospectively defined PMS or PMDD between the two groups of previous users. In a RCT with 25 women completing the study, GnRH treatment were tested in combination with two different HRT add-back doses of estradiol, in combination with progesterone and placebo. The higher dose of estrogen 1.5 mg in combination with progesterone induced significantly more pronounced symptoms than in combination with placebo. The lower dose, 0.5 mg gave less symptom recurrence in combination with progesterone. Exposure to violence was investigated among PMDD patients, healthy controls and gynecological patients. Among the participating women, gynecological patients, reported physical and/or emotional abuse significantly more often than did PMDD patients, as well as healthy controls. Chronic stress was investigated with diurnal cortisol, and low-dose dexamethasone test.  There was no difference in diurnal secretion of cortisol between PMDD patients and controls. No difference in the degree of dexamethasone suppression was found between PMDD patients and controls. According to the results from these studies, the main symptom provoking factor in women with PMDD appears to be the estradiol and progesterone fluctuations across the menstrual cycle, whereas chronic stress and intimate partner violence appears to be less relevant.