Elevated circulating Ang II activates neurons in the forebrain cardiovascular regulatory areas to cause sympatho-excitation and hypertension. We hypothesized that circulating Ang II causes neuronal activation in the SFO and thereby activates efferent pathways to the PVN, and chronically causes activation of aldosterone production in magnocellular neurons in PVN and SON, which amplifies neuronal activation in the PVN and central sympatho-excitatory pathways. The aim of the present study was to determine the pattern of neuronal activation in forebrain nuclei by circulating Ang II and to elucidate where in the hypothalamus Ang II may stimulate aldosterone biosynthesis. Dose related effects of circulating Ang II on BP were first assessed. Wistar rats instrumented with telemetry probes were infused subcutaneously with Ang II 150 and 500 ng/kg/min for 14 days. The subcutaneous infusion of Ang II at 150 ng/kg/min increased blood pressure gradually up to 20 mmHg and at 500 ng/kg/min up to 60 mmHg. Ang II at 500 ng/kg/min increased plasma Ang II by 4-fold. To assess effects of circulating Ang II on CNS pathways, Wistar rats were implanted subcutaneously with minipumps infusing 150 and 500 ng/kg/min Ang II for 1, 4 and 14 days. Three patterns of neuronal activation were observed by sc infusion of Ang II. The SFO was activated during the first day and remained activated for 4 days, but at 14 days showed diminished activation. MnPO did not show significant activation during the first day but, after several days the activation was high and then less by 14 days. Parvocellular PVN (pPVN), magnocellular PVN (mPVN) and SON showed an initial activation that increased over time. Chronic intracerebroventricular infusion of an aldosterone synthase inhibitor or a mineralocorticoid receptor (MR) blocker attenuated the increase in Fra expression in PVN but not SON, and prevented the decrease in SFO after 14 days infusion of Ang II. A significant increase in mRNA expression of steroidogenic acute regulatory protein (StAR), a rate limiting enzyme in aldosterone production was found in glia cells of PVN and SFO assessed by rt-PCR after 3 days subcutaneous infusion of Ang II at 500 ng/kg/min. Total expression of aldosterone synthase (CYP11B2) mRNA was increased in SFO, MnPO, SON and PVN after 3 days of infusion of Ang II. After 14 days no significant changes were observed in the expression of StAR or CYP11B2 mRNA. In comparison, in adrenal StAR mRNA expression increased after 3 days but no longer after 14 days. In contrast, CYP11B2 mRNA expression in adrenal increased after both 3 and 14 days of infusion. These findings may support our hypothesis that chronic elevation of circulating Ang II increases neuronal activity in CVOs, presumably leading to activation of the PVN and SON to induce an increase in aldosterone production in magnocelular PVN and SON. In the second phase activation of CVOs appears to diminish, but an aldosterone-dependent amplifying mechanisms, causes sustained activation of the PVN and thereby hypertension.

If one can come out as queer, how does one come out as queer in the Chinese context? More importantly, how exactly does one come out as “Chinese,” especially given the increasingly complex construction and remaking of “Chineseness” across the Taiwan Strait? Building on Hongwei Bao’s concept of the “queer comrade” as an analytical framework that acknowledges the temporal coevality of its circulation across postsocialist China and Taiwan, this comparative study of Zhang Yuan’s East Palace, West Palace and Ang Lee’s Eat Drink Man Woman explores archives of Chineseness and queerness in a transnational context. At the same time, through examining representations of cruising, traditional opera form, tables, kitchens, and food -- I argue that queer identities are not only about private sexual practices, but also about new family formations, political tensions, and intercultural exchanges. I take cues from archival studies to see them as alternative archival practices and subjectivities which channel new pathways to reimagine Queer Sinophone futurities. / Thesis / Master of Arts (MA)

<p>The G protein-coupled receptors (GPCRs) are important targets in drug discovery. In several cases, the endogenous ligands that activate the GPCRs of pharmaceutical interest are peptides. Unfortunately, peptides are in general not suitable as drugs, since the peptide structure is associated with several disadvantages, such as low oral bioavailability, rapid degradation and low receptor subtype selectivity. Thus, there is a strong need for drug-like nonpeptide ligands to peptide-activated GPCRs. However, to discover nonpeptide ligands that mimic the effect of the endogenous peptide, i.e. peptidomimetics, is a tremendous challenge. In fact, morphine and the related opioids were the only known examples of peptidomimetics before 1995 and these ligands were known long before the native endogenous peptide ligands were discovered. </p><p>The main objective of the work described in this thesis was to design, synthesize and biologically evaluate selective nonpeptide agonists to the peptide-activated GPCR AT₂. The AT₂ receptor belongs to the renin–angiotensin system, where the octapeptide angiotensin II (Ang II) is the major effector peptide. Ang II mediates its effects through the two GPCRs AT₁ and AT₂. The AT₁ receptor is already an established target in the treatment of hypertension. The physiological role of the AT₂ receptor, which is up-regulated in certain pathological conditions, is not fully understood but it seems to include positive effects such as vasodilatation, tissue repair, tissue regeneration and neuronal differentiation. </p><p>In the current investigation we started from the nonpeptide and nonselective (AT₁/ AT₂) compound L-162,313. This ligand is a known AT₁ receptor agonist but its effect on the AT₂ receptor was unknown at the start of this project. We were able to show that it acts as an agonist also at the AT₂ receptor. Furthermore, stepwise synthetic modifications of L-162,313 led to the identification of the first selective nonpeptide AT₂ receptor agonist. Following the discovery of this compound several selective nonpeptide AT₂ receptor agonists were identified. It was also revealed that a minor structural alteration of one of these compounds interconverted the functional activity from agonism to antagonism. The structural requirement for agonism vs antagonism was therefore studied. The functionality switch was suggested, at least partly, to be due to the spatial relationship between the methyleneimidazole group and the isobutyl side chain of the compounds. To further investigate the bioactive conformation(s) of this series of compounds enantiomerically pure analogues with conformationally constrained isobutyl chains were prepared. This study revealed that the direction of the isobutyl side chain determine whether the compounds act as agonists or antagonists at the AT₂ receptor. Further investigations are required to fully elucidate the bioactive conformation(s) of these nonpeptide AT₂ receptor agonists.</p><p>We believe that the selective nonpeptide AT₂ receptor agonists and antagonists identified in this thesis will serve as important research tools in the continuing investigation of the physiological role of the AT₂ receptor. We also believe that these drug-like compounds might provide potential leads in drug discovery processes.</p>

No description available.

Ziel der vorliegenden Arbeit war es, die Interaktion von ANP und Ang II im Bereich der blutdruckbestimmenden Widerstandsgefäße zu untersuchen. Ein besonderer Augenmerk wurde hierbei auch auf die Bedeutung von RGS2 gerichtet. Durch das Zusammenspiel der beiden funktionellen Antagonisten ANP und Ang II wird der Blutdruck reguliert. ANP und Ang II üben hierbei jeweils gegenteilige Effekte aus. Ang II hat vasokonstriktorische Effekte auf die Blutgefäße, vermindert die Natriurese und Diurese und erhöht den Sympathikustonus. ANP hingegen besitzt blutdruckmindernde Effekte, hervorgerufen durch Vasodilatation, gesteigerte Diurese, die Erhöhung der endothelialen Durchlässigkeit und der Hemmung des Sympathikustonus. Da nichts über die Interaktion dieser beiden Hormone in der Mikrozirkulation bekannt ist, wurden im Rahmen der Dissertation intravitalmikroskopische Studien der Mikrozirkulation des Musculus cremaster der Maus, in Anlehnung an der von Baez (1973) publizierten Methode, durchgeführt. Darüber hinaus wurden auch die Effekte von Ang II und ANP auf den Blutdruck durch invasive Blutdruckmessung untersucht. Der Durchmesser von präkapillären Arteriolen des M. cremaster wurde vor und während lokaler Superfusion von Ang II oder ANP gemessen. Ang II löste eine konzentrationsabhängige stabile Konstriktion aus. Bei der ausschließlichen Superfusion von ANP in verschiedenen Konzentrationen hingegen, zeigte sich kein Effekt auf den basalen Vasotonus. ANP war jedoch in der Lage, an Ang II vorkontrahierten Arteriolen, den konstriktorischen Effekt von Ang II aufzuheben und sogar darüber hinaus eine ausgeprägte Vasodilatation zu bewirken. Dieser Effekt konnte auch bei der invasiven Messung des mittleren arteriellen Blutdrucks nachgewiesen werden. Der durch Ang II ausgelöste Blutdruckanstieg wurde durch die zusätzliche Infusion von ANP gemindert. Ang II aktiviert die Kontraktion von glatten Gefäßmuskelzellen durch den Gαq-gekoppelten AT1-Rezeptor. RGS2 hingegen ist ein negativer Regulator von Gαq. Da von RGS2 bekannt ist, dass er von cGKI phosphoryliert und stimuliert wird (Osei-Owusu et al., 2007), stellte sich die Frage, ob ANP über RGS2 dem vasokonstriktiven Effekt von Ang II entgegenwirkt. Bei den Versuchen an RGS2-KO Mäusen zeigt sich hierbei, dass ANP nicht mehr in der Lage ist, den vasokonstriktiven Effekt von Ang II aufzuheben. Daraus ist nun der Schluss zu ziehen, dass RGS2 eine bedeutende Rolle für die Wechselwirkung zwischen ANP und Ang II in der Mikrozirkulation spielt und somit eine wichtige Aufgabe bei der Regulation des peripheren Widerstands und des Blutdrucks hat. / The aim of this dissertation was the investigation of the interactions between ANP and Ang II in the regulation of the tone of resistance vessels, with special focus on the role of RGS2. Arterial blood pressure is regulated by the interactions of ANP and Ang II, hormones which act as functional counterparts. Ang II leads to vasoconstriction, reduces natriuresis and diuresis, and enhances sympathetic tone. ANP on the contrary has hypotensive effects, mediated by vasodilatation, diuresis, increased endothelial permeability, and inhibition of sympathetic tone. Because nothing is known about the interaction of both hormones in resistance vessels, we performed intravital microscopy studies of the mouse cremaster microcirculation. The cremaster muscle was prepared as described by Baez (1973). Furthermore the effects of ANP and Ang II on arterial blood pressure were investigated by invasive blood pressure measurements. Arteriolar diameters were measured before and during local superfusion of Ang II or ANP. Ang II induced concentration dependent stable arteriolar constrictions. ANP did not affect diameters of unstimulated arterioles. However the peptide completely reversed the vasoconstrictory effect of Ang II. Moreover, in Ang II-preconstricted arterioles, ANP provoked a prominent dilatation. The interaction between ANP and Ang II was collaborated by invasive arterial blood pressure measurements. The hypertensive effect of Ang II was partly reversed by ANP. Ang II activates smooth muscle contraction through the the Gαq-coupled AT1 -receptor. The regulator of G protein signalling RGS2 is a negative regulator of Gαq. Because RGS2 is known to be phosphorylated and thereby stabilized by cGMP-dependent protein kinase (cGKI) (Osei-Owusu et al., 2007), we hypothesized that ANP counteracts the vasoconstrictory actions of Ang II by activation of RGS2. Indeed in RGS2-KO mice ANP failed to reverse the vasoconstrictory actions of Ang II. We conclude that RGS2 mediates the interplay between ANP and Ang II, which is critically involved in the regulation of peripheral resistance and arterial blood pressure.

The G protein-coupled receptors (GPCRs) are important targets in drug discovery. In several cases, the endogenous ligands that activate the GPCRs of pharmaceutical interest are peptides. Unfortunately, peptides are in general not suitable as drugs, since the peptide structure is associated with several disadvantages, such as low oral bioavailability, rapid degradation and low receptor subtype selectivity. Thus, there is a strong need for drug-like nonpeptide ligands to peptide-activated GPCRs. However, to discover nonpeptide ligands that mimic the effect of the endogenous peptide, i.e. peptidomimetics, is a tremendous challenge. In fact, morphine and the related opioids were the only known examples of peptidomimetics before 1995 and these ligands were known long before the native endogenous peptide ligands were discovered. The main objective of the work described in this thesis was to design, synthesize and biologically evaluate selective nonpeptide agonists to the peptide-activated GPCR AT2. The AT2 receptor belongs to the renin–angiotensin system, where the octapeptide angiotensin II (Ang II) is the major effector peptide. Ang II mediates its effects through the two GPCRs AT1 and AT2. The AT1 receptor is already an established target in the treatment of hypertension. The physiological role of the AT2 receptor, which is up-regulated in certain pathological conditions, is not fully understood but it seems to include positive effects such as vasodilatation, tissue repair, tissue regeneration and neuronal differentiation. In the current investigation we started from the nonpeptide and nonselective (AT1/ AT2) compound L-162,313. This ligand is a known AT1 receptor agonist but its effect on the AT2 receptor was unknown at the start of this project. We were able to show that it acts as an agonist also at the AT2 receptor. Furthermore, stepwise synthetic modifications of L-162,313 led to the identification of the first selective nonpeptide AT2 receptor agonist. Following the discovery of this compound several selective nonpeptide AT2 receptor agonists were identified. It was also revealed that a minor structural alteration of one of these compounds interconverted the functional activity from agonism to antagonism. The structural requirement for agonism vs antagonism was therefore studied. The functionality switch was suggested, at least partly, to be due to the spatial relationship between the methyleneimidazole group and the isobutyl side chain of the compounds. To further investigate the bioactive conformation(s) of this series of compounds enantiomerically pure analogues with conformationally constrained isobutyl chains were prepared. This study revealed that the direction of the isobutyl side chain determine whether the compounds act as agonists or antagonists at the AT2 receptor. Further investigations are required to fully elucidate the bioactive conformation(s) of these nonpeptide AT2 receptor agonists. We believe that the selective nonpeptide AT2 receptor agonists and antagonists identified in this thesis will serve as important research tools in the continuing investigation of the physiological role of the AT2 receptor. We also believe that these drug-like compounds might provide potential leads in drug discovery processes.

No description available.

Made available in DSpace on 2018-08-01T22:35:42Z (GMT). No. of bitstreams: 1 tese_10374_DISSERTAÇÃO CLAILSON - versão final completa.pdf: 1902806 bytes, checksum: 726c2abbd6e3c9c813489c17cf2eb970 (MD5) Previous issue date: 2016-10-27 / O objetivo desse trabalho foi analisar o efeito das condições de crescimento de árvores de eucalipto na grã, determinar a sua variabilidade no fuste e sua relação com as variáveis dendrométricas e as propriedades físico-mecânicas da madeira. Utilizaram-se duas populações de materiais genéticos distintos: i) 16 clones de Eucalyptus grandis x E. urophylla, com sete anos de idade, provenientes de teste clonal estabelecidos em Montezuma, Minas Gerais e Nova Almeida, Espírito Santo e ii) sete clones de E. grandis x E. urophylla, com 13 anos de idade, proveniente de plantios comerciais estabelecidos em Alcobaça, Bahia. Os efeitos das condições de crescimento e variáveis dendrométricas das árvores nos desvios da grã da madeira foram avaliados nos clones da primeira população, tendo previamente mensurados o diâmetro altura do peito (DAP), a altura comercial, o volume com casca e o fator de forma. A variação da grã no sentido medula-casca e base-topo foram determinadas nos materiais clonais da segunda população. Para ambas populações foi determinado o máximo desvio angular (MAD) pelo método de divisão radial, com posterior análise de imagens; a velocidade de propagação de ondas e o módulo de elasticidade dinâmico, obtidos por técnica não destrutiva de ultrassom, stress wave e vibração transversal; a resistência à compressão e cisalhamento paralelo as fibras, o módulo de ruptura e módulo de elasticidade por flexão estática, a densidade básica, o fator anisotrópico e a contração volumétrica do lenho. Observou-se que não houve diferença significativa dos valores de MAD entre as duas condições de crescimento, porém, com tendência de maiores desvios da grã na madeira de clones que cresceram em Nova Almeida. Para alguns clones na idade de 7 anos, houve correlações significativas positivas entre o MAD e as propriedades físicas e mecânicas. A velocidade de propagação das ondas ultrassônicas correlacionaram-se de forma negativa com os desvios da grã, para 12,5% dos clones da idade de 7 anos. Observou-se um decréscimo de 8,99% dos desvios da grã da base para o topo e acréscimo de 31,28% no sentido medula casca das árvores, e correlações significativas, com a velocidade de propagação de ondas de tensão e contração volumétrica da madeira, para os materiais genéticos da idade de 13 anos. Para a DB, CV, resistência à compressão paralela às fibras, MOR e MOE na flexão estática, MOEd por stress waver, ultrassom e vibração transversal, e velocidade de propagação de ondas ultrassônicas da madeira dos clones aos 13 anos, não houve correlações com os desvios da grã. Palavras-chave: Máximo desvio angular, Métodos não destrutivos, Ambientes contrastantes, Qualidade da madeira. trabalho foi analisar o efeito de dois locais de crescimento de clones de eucalipto na grã da madeira, bem como determinar a sua variação no sentido medula-casca e base-topo da árvore, e a sua relação com as variáveis dendrométricas, propriedades físico-mecânicas e velocidade de propagação de ondas acústicas e de tensão. Utilizaram-se duas populações de materiais genéticos distintos: i) 17 clones de Eucalyptus grandis x Eucalyptus urophylla, com sete anos de idade, provenientes de teste clonal estabelecidos em Montezuma, MG e Nova Almeida, ES, e ii) sete clones de E. grandis x E. urophylla, com 13 anos de idade, proveniente de plantios comerciais provinientes do sul da Bahia. Para avaliação do efeito do local de crescimento e variáveis dendrométricas das árvores na grã da madeira utilizou-se os clones da primeira população, tendo previamente mensurados o DAP, a altura comercial, o volume com casca e o fator de forma. Já para determinar a variação da grã no sentido medula-casca e base-topo, utilizaram-se os materiais clonais da segunda população. Para ambas populações, foi determinado o máximo desvio angular (MAD) pelo método de divisão radial, com posterior analise de imagens; a velocidade de propagação de ondas e o módulo de elasticidade dinâmico, obtidos por técnica não destrutiva de ultrassom, stress wave e vibração transversal; a resistência à compressão, flexão estática e cisalhamento paralelo as fibras, a densidade básica, o fator anisotrópico e a contração volumétrica do lenho. Não houve diferença significativa dos valores de MAD entre os locais de crescimento. Observou-se um decréscimo dos desvios de grã da base para o topo e acréscimo no sentido medula a casca das árvores, e correlações significativas, com a velocidade de propagação das ondas de tensão e contração volumétrica da madeira, para os materiais genéticos de 13 anos de idade. Para as demais propriedades físicas e mecânicas da madeira dos clones de 13 anos, não houve correlações com os desvios de grã. Para alguns clones da idade de 7 anos, houve correlações altamente significativas positivas entre o MAD e as propriedades físicas e mecânicas. A velocidade de propagação das ondas acústicas e de tensão correlacionaram de forma negativa com a grã, para alguns clones da idade de 7 e 13 anos. Palavras-chave: Máximo Desvio Angular; Métodos Não Destrutivos; Ambientes Contrastantes; Qualidade da Madeira.

No description available.

Des modèles de dysfonction érectile (DE) ont été développés et étudiés chez le rat. Cependant, peu de choses sont connues dans certains modèles présentant des facteurs de risque de la DE, en l’occurrence le rat soumis à une diète riche en glucose, le rat avec une restriction de croissance intra-utérine (RCIU) et le rat avec l’infusion continue de l’angiotensine (Ang) II en ce qui concerne l’évaluation de la fonction érectile in vivo. C’est ainsi que nous nous sommes proposés cette étude. La fonction érectile a été mesurée par la stimulation électrique du nerf caverneux à des cohortes de rats mâles Sprague-Dawley de différents âges comme suit: 1) des rats jeunes de 12 semaines d’âge, adultes reproducteurs à la retraite d’environ 30 semaines d’âge et des rats de 27 et 29 semaines soumis à une diète riche en glucose par l’eau de breuvage (10%) à court (1 semaine), moyen (6 semaines) et long (12 ou 13 semaines) termes; 2) des rats jeunes âgés de 12 semaines recevant une infusion soit de l’Ang II (200ng/kg/min) soit de la saline par mini-pompes osmotiques sous-cutanées pendant 1 et 2 semaines; et 3) des rats adultes âgés de 36 semaines avec une RCIU. La fonction érectile a été représentée par des courbes de variations de pression intracaverneuse (PIC) et d’aire sous la courbe (ASC) normalisées avec la pression artérielle moyenne (PAM) en réponse à la stimulation nerveuse à différents volts. À la fin des expériences, les animaux ont été sacrifiés, le sang recueilli pour le dosage de la glycémie et de l’insulinémie; le pénis, l’aorte thoracique et le cœur prélevés à des fins d’analyses protéique et histologique. La diète riche en glucose à court terme a eu un effet néfaste sur la fonction érectile chez le jeune rat mais bénéfique chez le rat adulte reproducteur; de même que pour les études à long terme, la diète riche en glucose a amélioré ou renversé la DE associée au vieillissement. Les rats avec RCIU ont exhibé une baisse très significative de la fonction érectile. Ces détériorations ou améliorations de la fonction érectile avec le glucose ou dans la RCIU ont été principalement associées à des modifications de l’expression de l’Akt, en plus d’une augmentation de l’insuline sérique dans les groupes avec le glucose. L’Ang II a entraîné une baisse de la fonction érectile, statistiquement très significative après 1 semaine et maintenue après 2 semaines de traitement, sans causer des changements morphologiques au cœur et à l’aorte thoracique. En conclusion : l’atteinte du système érectile se fait précocement dans les complications cardiovasculaires liées à l’activation du SRA, l’implication de l’Akt dans la modulation de la fonction érectile dépend de type de vieillissement et de la diète, le RCIU est un facteur de risque pour la DE. / Rat is a most rodent used for erectile function studies, and many erectile dysfunction (ED) rat models have been developed and studied. However, according to our knowledge, erectile function has never been studied in high-glucose fed rat model, intrauterine growth restriction rat model (IUGR) and continuous angiotensin (Ang) II infusion rat model. In this context, we set up this study. We mesured simultaneously mean arterial pression (MAP), intracavernosal pression (ICP), aire under the curve (AUC); and erectile function was obtained by variations of the ratio ICP/MAP and AUC/MAP in response to electrical stimulation of cavernosal nerve (0.89 – 6.50 Volts) in male Sprague-Dawley rats in different protocols as follow: 1) young (12 week old), procreator adult (~30 week old) and adult (27 and 29 week old) rats randomized and fed with high-glucose diet in water (10%) or simple water for a short (1 week), middle (6 weeks) and long (12 and 13 weeks) terms; 2) adult (36 week old) IUGR rats; 3) young (12 week old) rats randomized and received a chronic infusion of AngII (200 ng/kg/min) or saline by osmotic minipumps for 1 and 2 weeks. At the end of procedures, blood for measuring serum glucose and insulin in rats with chronic high-glucose diet was obtained, the heart was excised and left ventricle was weighed. Aorta and penis were excised, cleaned and a section of each was formalin fixed for histological studies and the rest snap frozen for protein studies. The short term high-glucose diet impacted negatively in young rats but positively in procreator adult rats; also, the erectile function was improved or reversed by chronic high-glucose diet in adult rats. We also observed a diminished erectile function in RCIU. The improvement or deterioration of erectile function was associated with changes in Akt expression, besides an increased insulin serum in rats with high-glucose diet. A diminished erectile function was observed after 1 week continuous Ang II infusion and was maintained after 2 week infusion without detectable structural changes on heart and aorta. In conclusion: this study suggests that erectile system is a precoce cible of cardiovascular complications of renin-angiotensin system. High-glucose diet deteriores erectile function but maskes the ageing induced-ED, RCIU is associated with ED in later life. Akt involvement in erectile function modulation depends on aging type and the diet.