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Participação do sistema endocanabinóide nas respostas comportamentais, hormonais e neuronais induzidas pela sobrecarga salina / Participation of the endocannabinoid system in behavioral, hormonal and neural responses induced by salt loadVechiato, Fernanda Maria Veanholi 10 April 2014 (has links)
O sistema endocanabinóide (eCB) tem sido reconhecido como um importante modulador da homeostase energética e recentemente estudos o apontam como um possível integrador da homeostase hidroeletrolítica. Estudos recentes do nosso laboratório demonstraram a participação do receptor canabinóide do tipo 1 (CB1R) no controle da secreção neurohipofisária em resposta a expansão hipertônica do volume extracelular. Dessa forma, o presente trabalho visou esclarecer a participação do sistema eCB, particularmente do CB1R, nas respostas neuronais, neuroendócrinas e comportamentais induzidas pela sobrecarga salina de 4 dias (SS). Uma vez que os animais em SS apresentam hipofagia induzida pela hiperosmolalidade, buscou-se avaliar as vias de integração do controle da homeostase energética e do balanço hidroeletrolítico por meio da introdução de um grupo em dieta pareada (pair fed, PF). De forma a investigar a hipótese acima, utilizou-se como ferramenta farmacológica o agonista seletivo CB1R, araquidonil-2-cloroetilamida (ACEA - 0,1g/5L), administrado por via intracerebroventricular (icv). Inicialmente, nosso trabalho mostrou que a SS promoveu aumento da expressão de CB1R tanto nos núcleos supra-óptico (NSO) e paraventricular (NPV) do hipotálamo quanto em estruturas da lâmina terminal [órgão subfornicial (SFO), o órgão vasculoso da lâmina terminal (OVLT) e o núcleo pré-óptico mediano (MnPO)]. Tais observações foram reforçadas pela análise microscópica destas regiões cerebrais por imunofluorescência, que evidenciou aumento da imunomarcação para CB1R no NPV, NSO e SFO em animais submetidos a SS. Estes resultados também mostraram que a maioria dos terminais pré-sinápticos CB1R-positivos estão localizados predominantemente na porção ventral do NSO, na qual predominam neurônios vasopressinérgicos. Os dados mostram ainda que todas as respostas induzidas pela SS foram revertidas após a reintrodução dos líquidos (RL, água e NaCl 0,3M). Já no grupo PF, não foram observadas alterações na expressão de CB1R em nenhuma das áreas avaliadas. No entanto, após a RL, os animais PF apresentaram hipoosmolalidade plasmática e aumento da expressão de CB1R na LT, sendo este último efeito aparentemente mediado por um aumento da expressão deste receptor no SFO. Em animais normoidratados, a administração central de ACEA produziu um aumento significativo na ingestão alimentar, sendo esta resposta ausente nos animais submetidos a SS, apesar do aumento da expressão de CB1R no hipotálamo verificada neste grupo. Entretanto, o pré-tratamento com ACEA foi capaz de potencializar a ingestão de água induzida pela SS, não produzindo efeitos significativos sobre este parâmetro no grupo PF. Este estudo demonstrou ainda que a SS não alterou as concentrações plasmáticas de angiotensina II (ANGII), porém promoveu aumento signficativo nas concentrações plasmáticas de corticosterona, vasopressina (AVP) e ocitocina (OT), além de diminuir a secreção de peptídeo natriurético atrial (ANP). Em animais submetidos a SS, o prétratamento com ACEA potencializou a secreção de corticosterona e preveniu o aumento da secreção de AVP e OT. Por outro lado, não foram observados efeitos da administração de ACEA sobre a secreção de ANP e ANGII induzida pela SS. Após a RL, o grupo SS apresentou normalização das concentrações plasmáticas hormonais, não sendo observados quaisquer efeitos da administração de ACEA nestas condições experimentais. No grupo PF, por sua vez, após a RL foi observada diminuição na secreção de OT e aumento nas concentrações plasmáticas de ANGII, efeitos estes não alterados pelo pré-tratamento com ACEA. Em conjunto, nossos dados sugerem que o CB1R participa ativamente das respostas homeostáticas comportamentais e neuroendócrinas desencadeadas pela SS, sendo estas respostas especificamente relacionadas ao controle da homeostase hidrossalina e não secundárias à hipofagia induzida pela hiperosmolalidade. Desta forma, conclui-se que a participação do CB1R na homeostase hidroeletrolítica ocorre em paralelo e independentemente da modulação exercida por este receptor sobre a homeostase energética. / The endocannabinoid system (eCB) has been recognized as an important modulator of energy homeostasis and recent studies suggest that this system may play a possible integrator role on hydromineral homeostasis. Recent studies from our laboratory demonstrated the involvement of the type 1 cannabinoid receptor (CB1R) in the control of neurohypophyseal secretion in response to hypertonic extracellular volume expansion. Therefore, the present study aimed to clarify the involvement of the ECB system, particularly of CB1Rs, in neuronal, neuroendocrine and behavioral responses induced by 4 days of salt load (SS). Since the animals submitted to SS exhibit a well known state of hyperosmolality-induced hypophagia, we attempted to evaluate the integrated control of energy homeostasis and hydroelectrolytic balance through the introduction of a paired diet group (pair fed, PF). In order to achieve these goals, this study employed as a pharmacological tool the CB1R selective agonist, arachidonoyl-2\'-chloroethylamide (ACEA-0.1g/5L), administered intracerebroventricularly (icv). Initially, our work showed that SS increased the expression of CB1R in both supraoptic (SON) and paraventricular (PVN) nuclei of the hypothalamus, as well as in the structures of the lamina terminalis [subfornical organ (SFO), organum vasculosum of the lamina terminalis (OVLT) and median preoptic nucleus (MnPO)]. These observations were reinforced by the microscopic analysis of these brain regions by immunofluorescence, which showed increased immunostaining for CB1R in the PVN, SON and SFO in animals submitted to SS. These results also showed that most of the presynaptic CB1R-positive terminals are located predominantly in the ventral part of the SON, which is characterized by the presence of vasopressinergic neurons. The data also showed that all SS-induced responses were reversed after reintroduction of fluids (RF, water and 0,3M NaCl). On the other hand, no changes in the expression of CB1R in any of the evaluated areas were observed in the PF group. However, after RF, PF animals showed hypoosmolality and increased expression of CB1R in the LT, being the latter effect apparently mediated by increased expression of this receptor in SFO. In euhydrated animals, the central administration of ACEA produced a significant increase in food intake, being this response absent in animals submitted to SS, despite the increased expression of CB1R in the hypothalamus observed in this group. However, pretreatment with ACEA was able to potentiate SS-induced water intake, producing no significant effect on this parameter in the PF group. This study also demonstrated that SS did not alter plasma concentrations of angiotensin II (ANG II), but significantly increased plasma concentrations of corticosterone, vasopressin (AVP) and oxytocin (OT), and decreased the secretion of atrial natriuretic peptide (ANP). In animals submitted to SS, pretreatment with ACEA enhanced the secretion of corticosterone and prevented the increased secretion of AVP and OT. Moreover, no effect of ACEA was observed on the SS-induced ANG II and ANP secretion. After RF, the SS group showed normalization of hormonal plasma concentrations, and no effects of ACEA administration were verified under these experimental conditions. After RF, the PF group exhibited a decrease in OT secretion and increased plasma concentrations of ANG II, effects that were not altered by pretreatment with ACEA. Taken together, our data suggest that CB1Rs actively participate in behavioral and neuroendocrine homeostatic responses triggered by SS, and that these responses were specifically related to the control of hydromineral homeostasis and not secondary to the hyperosmolality-induced hypophagia. Therefore, we conclude that the involvement of CB1R in electrolyte homeostasis occurs in parallel and independently of the modulation exerted by this receptor on energy homeostasis.
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Influência das condições obstétricas ao nascimento sobre padrões de vitalidade e bioquímica neonatal na espécie canina / Canine neonatal vitality and biochemistry profile under distinct obstetric conditionsLúcio, Cristina de Fátima 29 May 2008 (has links)
Em Medicina Veterinária, os avanços em Neonatologia são escassos quando comparados aos da Medicina Humana. Dentre as possíveis causas para esta situação atual destacam-se as particularidades fisiológicas deste período. Os objetivos do presente estudo foram: estabelecer os valores normais de algumas variáveis laboratoriais de neonatos nascidos de parto eutócico, identificar eventuais alterações metabólicas maternas e dos neonatos nascidos em diferentes condições obstétricas, verificar os efeitos da administração de ocitocina sob variáveis neonatais e maternas e mensurar os níveis de cortisol materno e neonatal como forma de estudar as diferentes situações de estresse no momento do parto. Vinte e nove fêmeas caninas foram alocadas em 3 grupos, de acordo com o tipo de parto: eutocia (grupo 1), distocia corrigida por manobras obstétricas ou cesariana (grupo 2) e indução de contrações uterinas com ocitocina (grupo 3). Cinqüenta e um neonatos foram avaliados por meio do sistema Apgar e temperatura corpórea ao nascimento, 5 minutos e 1 hora após o nascimento, bem como por avaliação hemogasométrica, dosagem de cortisol e glicemia ao nascimento e após 1 hora. A avaliação materna constituiu no controle da pressão arterial, monitorização cardíaca, glicemia e dosagem de cortisol em momentos pontuais no pré, intra e pós-parto. Os neonatos dos distintos grupos apresentaram acidose mista associada à hipóxia ao nascimento, com maior comprometimento metabólico nos filhotes do grupo 3. Após 1 hora, recuperaram-se do componente respiratório, mantendo apenas o quadro de acidose metabólica por maior comprometimento da hipóxia. A avaliação neonatal pelo escore Apgar demonstrou que filhotes do grupo 2 nascem em maior depressão que neonatos dos grupos 1 e 3, porém todos apresentam adequada recuperação após 1 hora. Nas parturientes, a administração de ocitocina favoreceu a elevação da pressão arterial para níveis normais durante o trabalho de parto, bem como o aumento da glicemia. Neonatos nascidos por manobra obstétrica ou cesariana apresentaram maior concentração de cortisol plasmático ao nascimento, em comparação aos grupos 1 e 3. Contudo, todos os neonatos apresentaram redução significativa dos níveis de cortisol após 1 hora do nascimento. Por outro lado, foi possível verificar maior concentração sérica deste hormônio após o término do parto nas fêmeas submetidas à infusão de ocitocina. Em conclusão, a administração de ocitocina é responsável por maiores alterações metabólicas em neonatos; na parturiente, a administração de ocitocina promove alterações na pressão arterial, glicemia e aumento da liberação de cortisol; a manobra obstétrica ou cesariana promove maior estresse neonatal ao nascimento. / Studies accomplishing canine neonatology are scarce in Veterinary Medicine comparing to Human Neonatology due to the particularity of this refered period. The aims of the present study were to establish standard laboratorial values of the canine neonate, identify metabolic changes of bitches and neonates born under different obstetric conditionsl, verify the consequences of dystocia treated medically by oxytocin administration on maternal and neonatal variables and to measure maternal and neonatal cortisol levels on distinc stress situations during parturition. Twenty nine canine females were allocated into 3 groups according to the obstetric conditions: eutocia (group 1; n=10), manipulative obstetric assistance or cesarean section (group 2; n=10) and maternal dystocia treated with oxytocin (group 3; n=9). Fifty one neonates were submitted to a clinical evaluation by Apgar scoring and body temperature measurement immediately after birth, at 5 and 60 minutes postnatal; and hemogasometric evaluation, blood glucose and cortisol assay immediately after birth and 60 minutes postnatal. Maternal noninvasive arterial blood pressure, blood glucose and cardiac monitoring were peformed during the first stage of labor, intra-partum, immediately after the last puppy was born and 1 hour later. Neonates from distinct groups showed mixed acidosis in addition to hypoxemia at birth. Neonates remained under metabolic acidosis even after 1 hour of birth due to a detrimental effect on hypoxia. Comparing the results among groups, puppies from group 2 showed significantly lower Apgar score at birth. However, 1 hour later all neonates showed full recovery. Dams subjected to oxytocin infusion showed an increase in blood pressure, hence switching to a normotension status and also presented higher glucose level during parturition. Manipulative obstetric assistance or cesarean section arised neonatal cortisol levels at birth. However, all neonates exhibited significantly lower cortisol concentration after 1 hour of birth. Bitches of group 3 showed significantly higher cortisol level immediatly after whelping. In conclusion, dystocia treated medically by oxytocin infusion resulted in more intense metabolic alterations compared to neonates born under eutocia; oxytocin administration promotes blood pressure enhance, glucose alterations and increase in maternal stress; manipulative obstetric assistance or cesarean section increased neonatal cortisol release at birth.
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Participação das vias intracelulares moduladas pelo monóxido de carbono na regulação do equilíbrio hidroeletrolítico / Participation of intracellular pathways modulated by carbon monoxide in the regulation of hydroeletrolitic balanceJuliana Bezerra Medeiros de Lima 04 December 2018 (has links)
O monóxido de carbono (CO) tem um importante papel na fisiologia animal incluindo plasticidade sináptica, processos de memória e aprendizagem, inflamação e liberação de neuropeptídios hipotalâmicos. Recentemente tem sido demonstrado que a liberação de vasopressina (AVP) e ocitocina (OT) em resposta a alterações no balanço hidromineral pode ser modulada por esse neuromodulador gasoso, contudo, os mecanismos pelos quais essa modulação ocorre ainda não foram elucidados. Nesse sentido, nós mapeamos possíveis alvos intracelulares do CO pelos quais esse gás poderia afetar as respostas neuroendócrinas tais como as propriedades passivas de membrana de neurônios magnocelulares do núcleo supraóptico (SON), via de sinalização da p38 MAPK, sistema óxido nítrico (NO)/óxido nítrico sintase (NOS), participação de astrócitos hipotalâmicos e a resposta antioxidante à diferentes condições de hidratação: euhidratação, 24 e 48 horas de privação hídrica. Nós observamos que a inibição da formação central de CO reduziu o aumento das concentrações plasmáticas de AVP e OT induzido pela privação hídrica, bem como inibiu a atividade NOS nos grupos hidratado e desidratado por 48 horas (PH 48); enquanto a razãoe p-p38 MAPK/p38 MAPK ratio foi aumentada pela doação central de CO em todas as condições de hidratação analisadas. Além do mais, nós demonstramos a expressão de HO-1, p38 MAPK e p-p38 MAPK em astrócitos hipotalâmicos. Em relação à resposta antioxidade, observamos que camundongos silenciados para Nrf2 no SON tem a resposta à desidratação prejudicada. Esses dados indicam o papel do CO como uma molécula neuromodulatória nas respostas neuroendócrinas à desidratação onde pode exercer sua função via resposta antioxidante em tempo mais curto de restrição hídrica e via sistema do NO em tempo mais prolongado / Carbon monoxide plays important roles in animal physiology including synaptic plasticity, learning and memory processes, inflammation and hypothalamic neuropeptide release. Recently it has been demonstrated that the AVP and OT release in response to changes in hydromineral balance can be modulated by this gaseous neuromodulator; however, the mechanisms by which this modulation occurs need to be elucidated. In order to answer this questioning, we evaluated the CO effect on neuroendocrine responses, SON magnocellular neurons passive membrane properties, p38 MAPK signaling, NO/NOS system and astrocytes participation in rats during control or 24/48 WD conditions. We observed that CO formation inhibition reduced the water deprivation-induced increase in plasma AVP and OT concentration and NOS activity in basal and 48 WD groups; while p-p38 MAPK/p38 MAPK ratio was increased by central CO donation in both euhydrated and dehydrated conditions. Furthermore, we demonstrated HO-1, p38 MAPK and p-p38 MAPK expression in MBH astrocytes. These data indicate the CO role as neuromodulatory molecule in neuroendocrine responses to dehydration where it might play its biological functions through p38 MAPK phosphorylation and NOS activity in a water restriction longer period
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Physiopathologie et développement de stratégies thérapeutiques dans le cadre de pathologies neurodéveloppementales : investigation des fonctions sensori-motrices à la naissance dans des modèles murins pour les syndromes de Prader Willi et Schaaf Yang / Physiopathology and developement of therapeutical strategies in neurodevelopmental pathologies : investigation of neonatal sensori motor functions in mouse models for Prader Willi and Schaaf Yang syndromesCaccialupi Da Prato, Laura 29 May 2019 (has links)
Le Syndrome de Prader Willi (SPW) est une pathologie neurodéveloppementale d’origine génétique présentant un tableau clinique complexe et évoluant avec l’âge.Elle est caractérisée par des déficits sensori-moteurs présents dès la naissance se manifestant par une hypotonie, une absence du réflexe de succion et des troubles respiratoires incluant des apnées obstructives et centrales constituant la première cause de mortalité. Les patients présentent un certain degré d’altération cognitive et un déficit de comportement associé aux troubles du spectre autistique (TSA). Des déficits sensoriels, se manifestent dès la naissance et sont caractérisés par un seuil élevé à la douleur, une altération de la thermosensibilité et de la thermorégulation se manifestant par des épisodes d’hyper- ou d’hypothermie pouvant être fatals chez le nourrisson. Ces déficits sont une caractéristique fondamentale du diagnostic des TSA et sont retrouvées chez 90% des patients autistes. Mon travail de thèse a consisté à étudier la physiopathologie de la fonction respiratoire et la thermosensibilité néonatales et leur altération dans la pathologie neurodéveloppementale. Ces études ont été rendues possibles grâce à l’utilisation de deux modèles murins:les Ndn-/- et Ml2+/-p.Ndn est impliqué dans le SPW et l’étude des souris Ndn-/-,a permis de décrypter l’origine des déficits sérotoninergiques responsables des troubles respiratoires.Ml2,est impliqué dans le SPW et le syndrome de Schaaf Yang (SSY) et l’investigation des souris Ml2+/-p a mis en évidence l’existence d’un déficit de thermosensibilité néonatale et démontré l’implication du système ocytocinergique dans la modulation de cette fonction sensorielle. / Prader Willi Syndrome (PWS) is a neurodevelopemental genetic disease with a symptomatology which evolves with age. This pathology is mainly characterized by sensory motor defects at birth such as severe infantile hypotonia with poor suck and failure to thrive and respiratory disturbances including both obstructive and central sleep apnea which represent the most common cause of death. PWS patients also have some cognitive impairment and behavioral disturbances, overlapping with autism spectrum disorder (ASD). Sensory deficits, are already present at birth and are characterized by high pain threshold and a defect in thermosensibility and thermoregulation manifested by episode of hypo- or hyperthermia which can be fatal in newborns. Moreover, these deficits are a core aspect of ASD affecting 90 % of children. My thesis work consisted in studying the pathophysiology of respiratory function during the early postnatal stages as well as neonatal thermosensitivity and its alteration in neurodevelopmental pathology. These studies were made possible by the use of two mouse models: Ndn-/- and Magel2+/-p mice. Ndn is involved in PWS and summarizing the respiratory disorders found in patients. Ml2 is involved in both SPW and Schaaf Yang syndrome (SYS), a recently discovered pathology overlapping with ASD. Ndn-/-mice allowed me to decipher the underlying mechanism behind the serotonin deficits responsible for respiratory disorders, thus allowing me to develop an effective therapeutic strategy. The investigation of Ml2+/-p mice revealed neonatal cool sensitivity deficit and demonstrated the involvement of the oxytocinergic system in the modulation of this sensory function.
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在大白鼠的脊髓層次上由催產素以及血管收縮素IV所個別誘導的抗疼痛敏化之間可能的關聯性 / A possible correlation between the oxytocin-induced and angiotensin IV-induced anti-hyperalgesia at the spinal level in rats張恩沛 Unknown Date (has links)
在本實驗室之前的研究中顯示在發炎狀態的大白鼠上以intrathecal (i.t.) 方式給予angiotensin IV (Ang IV) ,Ang IV 是insulin-regulated aminopeptidase (IRAP) inhibitor,可以減少腳掌發炎之大白鼠的疼痛過敏化。然而,這個由Ang IV所產生之效果背後的機制還未被完全釐清。
在這次的實驗中,我們利用由carrageenan引起腳掌腫脹之大鼠進行plantar test來研究Ang IV所產生之抗疼痛過敏化其中可能機制。由於有文獻指出,在發炎狀態的大白鼠上以intrathecal (i.t.) 方式給予oxytocin可產生一劑量相關性的抗疼痛過敏化作用,因此我們推測在大白鼠的脊髓層次上由oxytocin以及Ang IV所個別誘導的抗疼痛過敏化之間可能有關聯性。利用 i.t.單獨給予atosiban (selective oxytocin receptor antagonist) 可以觀察到一個較強烈的疼痛過敏化現象,然而合併給予atosiban,可使Ang IV所產生的抗疼痛過敏化完全被阻斷掉。因此我們推測oxytocin在以intrathecal (i.t.) 方式給予Ang IV而阻斷IRAP的活性,進而產生抗疼痛過敏化作用的過程中是一個主要的IRAP受質。
當我們在carrageenan誘導疼痛過敏化的大白鼠上單獨給予低劑量之oxytocin並沒有產生統計上顯著之抗疼痛過敏作用。然而合併給予oxytocin和Ang IV後,則可以有觀察到Ang IV 能增加並且延長oxytocin所引起的抗疼痛過敏化作用。
就內生性oxytocin來看,電刺激paraventricular hypothalamic nucleus (PVN)已被證實可以增加內生性的oxytocin分泌到脊髓。而這樣的一個神經路徑被發現和疼痛的調節具有很密切的關聯性。從我們的結果中,我們發現在carrageenan誘導疼痛過敏化的大白鼠上,i.t.給予Ang IV可以延長PVN電刺激產生的抗疼痛過敏化作用,由此推測 Ang IV可能可以保護內生性oxytocin不被分解或失去活性。
除了oxytocin之外,IRAP在體外的實驗中被證實可以分解數種具生理活性之peptides 的N-terminal amino acid,其中包括vasopressin, bradykinin 以及 enkephalin等。在這些物質中,bradykinin已被證實在週邊發炎的過程中具有重要的調控效果,若IRAP在週邊組織扮演了一個分解促發炎物質的角色,利用Ang IV也許可以去阻斷IRAP之活性進而增加這些促發炎物質。因此,我們在由carrageenan誘導疼痛過敏化的動物模式上利用腳掌局部注射 Ang IV來探討在發炎部位Ang IV可能的作用。我們猜測Ang IV 可能可以調控不同物質(例如:bradykinin)而在發炎部位產生局部之作用, 但結果顯示在疼痛過敏化以及腫脹程度上,Ang IV並不具有調控週邊組織發炎過程的能力。所以推測Ang IV在週邊發炎位置可能並沒有扮演非常重要的角色。
總而言之,本實驗結果證實了Ang IV以及 oxytocin在發炎大白鼠的脊髓層次上所個別引起之抗疼痛過敏化作用之間具有相關性,其中的機制可能是Ang IV在發炎大白鼠的脊髓層次上藉由抑制IRAP降解oxytocin的活性,進而產生抗疼痛過敏化的效果。 / In our previous study, we showed that intrathecal (i.t.) administration of angiotensin IV (Ang IV), an insulin-regulated aminopeptidase (IRAP) inhibitor, could attenuate hyperalgesia in rats with inflammation. However, the underlying mechanism(s) for this effect of Ang IV was not clarified yet. Using the plantar test in rats with carrageenan-induced paw inflammation, we attempted to investigate the possible mechanism(s) of Ang IV in the present study. Because it has been reported that i.t. administration of oxytocin produced a dose-dependent anti-hyperalgesia effect in rats with inflammation, we speculate that there is a possible correlation between the oxytocin-induced and angiotensin IV-induced anti-hyperalgesia at the spinal level in rats. Using i.t. co-administered atosiban (a selective oxytocin receptor antagonist), the anti-hyperalgesia effect of Ang IV was completely abolished, although a severer hyperalgesia was observed in rats receiving atosiban alone. This indicates that oxytocin could be the major substrate of IRAP responsible for the anti-hyperalgesia caused by intrathecal administration of Ang IV, which blocked the activity of IRAP. Using i.t. administration of oxytocin in rats with carrageenan-induced hyperalgesia, the anti-hyperalgesia effect of oxytocin was potent and significant. When Ang IV was co-administered with the low dose of oxytocin, a significant enhancing effect of Ang IV on anti-hyperalgesia of oxytocin was observed. In view of the endogenous oxytocin, electrical stimulation of the paraventricular hypothalamic nucleus (PVN) has been proved to cause the increase of oxytocin release at the spinal cord. This neural pathway has been found to be highly related to the modulation of pain. In our results, we found that i.t. administration of Ang IV could prolong the anti-hyperalgesia induced by PVN stimulation. This suggests a possible protective effect of Ang IV on endogenous oxytocin degradation/dysfunctioning. In addition to oxytocin, it was well known that IRAP is able to cleave the N-terminal amino acid from several bioactive peptides in vitro, including vasopressin, bradykinin and enkephalin. Among these substrates, bradykinin has been demonstrated to be an important mediator in peripheral inflammation. It is a pro-inflammatory substance that can be enhanced by Ang IV, if the peripheral IRAP plays a role in its degradation. Therefore, we examined the possible local effect of intraplantarly injected Ang IV on the carrageenan-induced hyperalgesia in the same model. However, our results showed no effect of local Ang IV on hyperalgesia and paw edema, indicating that Ang IV may not be able to regulate the peripheral inflammatory process. Overall, the present study verified the possible interaction between the oxytocin-induced and angiotensin IV-induced anti-hyperalgesia at the spinal level in rats with inflammation. It suggests that Ang IV may act though the inhibition of the activity of IRAP to reduce the degradation of oxytocin, thereby lead to anti-hyperalgesia in rats with inflammation.
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Tactile touch in intensive care : Nurses' preparation, patients' experiences and the effect on stress parametersHenricson, Maria January 2008 (has links)
<p>Aim: The overall aim of this thesis was to acquire knowledge about whether tactile touch as a complementary method can (i) promote comfort and (ii) reduce stress reactions during care in an intensive care unit (ICU) Method: In Paper I, five nurses with a touch therapist training were interviewed about their experiences of preparation before giving tactile touch in an ICU. To analyse the meaning of preparation as a phenomenon, Giorgi’s descriptive phenomenological approach was used. In Paper II and III a randomised controlled trial was set up to investigate the effects of a five-day tactile touch intervention on patients’ oxytocin levels in arterial blood (II), on patients’ blood pressure, heart rate and blood glucose level, and on patients’ levels of anxiety, sedation and alertness (III). Forty-four patients were randomised to either an intervention group (n = 21) or a control group (n = 23). Data were analysed with non-parametric statistics. In Paper IV, six patients who had received the tactile touch intervention were interviewed to illuminate the experience of receiving tactile touch during intensive care. To gain a deeper understanding of the phenomenon and to illuminate the meaning, Ricoeur’s phenomenological hermeneutical method, developed by Lindseth and Norberg, was used. Findings: The nurses need four constituents (inner balance, unconditional respect for the patients’ integrity, a relationship with the patient characterized by reciprocal trust and a supportive environment) to be prepared and go through the transition from nurse to touch therapist (I). In the intervention study, no significant differences were shown for oxytocin levels between intervention and control group over time or within each day (II). There were significantly lower levels of anxiety for patients in the intervention group. There were no significant differences between the intervention and control groups for blood pressure, heart rate, the use of drugs, levels of sedation or blood glucose levels (III). The significance of receiving tactile touch during intensive care was described as the creation of an imagined room along with the touch therapist. In this imagined room, the patients enjoyed tactile touch and gained hope for the future (IV). Conclusion: Nurses needed internal and external balance to be prepared for providing tactile touch. Patients did not notice the surroundings as much as the nurses did. Patients enjoyed the tactile touch and experienced comfort. The impact on stress parameters were limited, except for levels of anxiety which declined significantly. The results gave some evidence for the benefit of tactile touch given to patients in intensive care.</p>
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An Investigation of the Effects of Pitocin for Labor Induction and Augmentation on Breastfeeding SuccessLewis, Megan J. 23 April 2012 (has links)
Rates of labor induction and augmentation have been increasing in recent decades (Glantz, 2005). According to the Listening to Mothers II survey, half of all labors in the U.S. are induced or augmented with Pitocin or other synthetic form of the hormone oxytocin (Declercq et al., 2006). Oxytocin, a naturally occurring hormone released in the pituitary gland, is involved in the stimulation of uterine contractions during labor and in the milk ejection reflex during breastfeeding, and research suggests it also has various effects on the brain, such as eliciting maternal behavior. However, studies have shown that exogenous oxytocin can interfere with the natural production and regulation of oxytocin and can have adverse effects on the fetus and mother. Therefore, I predict that the induction or augmentation of labor with Pitocin will negatively affect breastfeeding following birth. The proposed study will compare LATCH scores, used in hospitals to measure postpartum breastfeeding success, of dyads exposed to intravenous Pitocin prior to birth with control dyads that had no exposure to Pitocin during labor. It is hypothesized that dyads exposed to Pitocin will have significantly lower LATCH scores than controls. Given the countless health benefits of breastfeeding for both mother and infant, the results of this study will have important implications for the evaluation of common practices during labor and birth.
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Protective signaling of oxytocin in an in vitro model of myocardial ischemia - reperfusionGonzalez Reyes, Araceli 12 1900 (has links)
Introduction : La prévention de la mort de cellules cardiaques contractiles suite à un épisode d'infarctus du myocarde représente le plus grand défi dans la récupération de la fonction cardiaque. On a démontré à maintes reprises que l'ocytocine (OT), l'hormone bien connue pour ses rôles dans le comportement social et reproductif et couramment utilisée dans l’induction de l’accouchement, diminue la taille de l'infarctus et améliore la récupération fonctionnelle du myocarde blessé. Les mécanismes de cette protection ne sont pas totalement compris.
Objectif : Étudier les effets d'un traitement avec de l'ocytocine sur des cardiomyocytes isolés en utilisant un modèle in vitro qui simule les conditions d'un infarctus du myocarde.
Méthodes : La lignée cellulaire myoblastique H9c2 a été utilisée comme modèle de cardiomyocyte. Pour simuler le dommage d'ischémie-reperfusion (IR), les cellules ont été placées dans un tampon ischémique et incubées dans une chambre anoxique pendant 2 heures. La reperfusion a été accomplie par la restauration du milieu de culture régulier dans des conditions normales d'oxygène. L'OT a été administrée en présence ou en absence d'inhibiteurs de kinases connues pour être impliquées dans la cardioprotection. La mortalité cellulaire a été évaluée par TUNEL et l'activité mitochondriale par la production de formazan pendant 1 à 4 heures de reperfusion. La microscopie confocale a servie pour localiser les structures cellulaires.
Résultats : Le modèle expérimental de l'IR dans les cellules H9c2 a été caractérisé par une diminution dans la production de formazan (aux alentours de 50 à 70 % du groupe témoin, p < 0.001) et par l'augmentation du nombre de noyaux TUNEL-positif (11.7 ± 4.5% contre 1.3 ± 0.7% pour le contrôle). L'addition de l'OT (10-7 a 10-9 M) au commencement de la reperfusion a inversé les effets de l'IR jusqu'aux niveaux du contrôle (p < 0.001). L'effet protecteur de l'OT a été abrogé par : i) un antagoniste de l'OT ; ii) le knockdown de l'expression du récepteur à l'OT induit par le siRNA ; iii) la wortmannin, l'inhibiteur de phosphatidylinositol 3-kinases ; iv) KT5823, l'inhibiteur de la protéine kinase dépendante du cGMP (PKG); v) l'ODQ, un inhibiteur du guanylate cyclase (GC) soluble, et A71915, un antagoniste du GC membranaire. L'analyse confocale des cellules traitées avec OT a révélé la translocation du récepteur à l'OT et la forme phosphorylée de l'Akt (Thr 308, p-Akt) dans le noyau et dans les mitochondries.
Conclusions : L'OT protège directement la viabilité des cardiomyocytes, lorsqu'elle est administrée au début de la reperfusion, par le déclenchement de la signalisation du PI3K, la phosphorylation de l'Akt et son trafic cellulaire. La cytoprotection médiée par l'OT implique la production de cGMP par les deux formes de GC. / Introduction: The prevention of the death of contractile cardiac cells following an episode of myocardial infarction represents the largest challenge in the recovery of myocardial function. Oxytocin, the hormone best known for its roles in reproduction and social behaviour and used commonly for the induction of parturition, has been repeatedly demonstrated to decrease the infarct size and to ameliorate the functional recovery of the injured myocardium. The mechanisms for this protection are incompletely understood.
Objective: To study the effects of oxytocin treatment on isolated cardiomyocytes using an in vitro model simulating the conditions of a myocardial infarction.
Methods: The cardiomyoblastic cell line H9c2 was used as a model of cardiomyocyte. For IR injury, the cells were placed in ischemic buffer and incubated in an anoxic chamber for 2 hours. Reperfusion was achieved by restoring cell media under normoxic conditions. OT was administered in the presence or absence of enzyme inhibitors. Cell death was evaluated by TUNEL and mitochondrial activity by formazan production during 1-4 hours of reperfusion. Confocal microscopy served for localization of cell structures.
Results. The experimental model of IR in H9c2 cells was characterized by decreased formazan production (at the range of 50-70% of normoxic control, p < 0.001) and by the increased number of TUNEL-positive nuclei (11.7±4.5 vs. 1.3±0.7% in normoxic control). The addition of OT (10-7 to 10-9 M) at the onset of reperfusion reversed the effects of IR to the control levels (p < 0.001). The protective effect of OT was abrogated by: i) an OT antagonist, OTA and siRNA-mediated OT receptor knockout; ii) the phosphatidylinositol 3-kinases inhibitor wortmannin; iii) the cGMP-dependent protein kinase (PKG) inhibitor, KT5823. Soluble guanylate cyclase (GC) inhibitor ODQ and particulate GC antagonist A71915 only partially blocked the protective effects of OT. Confocal analysis of OT-treated cells revealed translocation of OT receptor and the phosphorylated form of Akt (Thr 308, p-Akt) into the nucleus and mitochondria.
Conclusions: OT directly protects cardiomyocyte viability if administered at the onset of reperfusion by triggering signaling of Pi3K, Akt phosphorylation and its cellular trafficking. OT-mediated cytoprotection involves cGMP production by both forms of GC.
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Rho-Kinase-Mediated Diphosphorylation of Myosin Regulatory Light Chain is a Unique Biochemical Mechanism in Human Uterine MyocytesAguilar, Hector N Unknown Date
No description available.
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Maternal Separation in the Rat : The Short- and Long-term effects of Early-life Experience on Neuropeptides, Monoamines and Voluntary Ethanol ConsumptionOreland, Sadia January 2009 (has links)
Early-life experience has profound effects on the individual’s neurobiology and behaviour later in life. The rodent animal experimental model maternal separation (MS) was used to study this more in detail. The MS model involves short and prolonged postnatal separations simulating an emotionally safe and stressful environment, respectively. The aims of the thesis were to examine the impact of individual MS on ethanol consumption and on brain dopamine and serotonin systems in adult male rats. Furthermore, the influence of separation conditions on the short- and long-term consequences of MS on several neurotransmitter systems was examined. Rat pups were assigned to either litter-wise MS for 15 or 360 minutes (MS15l or MS360l) or individual MS for 15 or 360 minutes (MS15i or MS360i). Control rats were subjected to conventional animal facility rearing (AFR). Ethanol intake was assessed in a two-bottle free-choice paradigm. Neuropeptides were analyzed with radioimmunoassay, monoamines and metabolites with electrochemical detection and gene expression with qPCR. Using the MSi paradigm, minor effects on voluntary ethanol consumption were observed. However, the monoaminergic responses elicited by ethanol were dependent on the early-life environment. Furthermore, short- and long-term consequences of MS on serotonin, opioid, oxytocin and vasopressin systems were studied. Multiple neurobiological measurements in one and the same rat offered a unique possibility to examine the effects of duration (MS15 versus MS360) and condition (l versus i) of MS. Time-, region-, sex- and transmitter-specific effects were observed. More pronounced differences were seen in serotonin measures and oxytocin in young rats. In adults these differences in basal levels were normalized. Opioid peptides differed in stress-related brain areas in young rats and in limbic areas in adults. Rats subjected to the MS15l environment that relates to natural conditions generally exhibited a different neurobiological profile than other groups. AFR rats, i.e. conventional control rats, were more similar to the putative most stressful condition MS360. Taken together, the networks examined in the present thesis are important for the establishment of normal social behaviour and derangements in these systems may result in neurobiological changes leading to the susceptibility for psychopathological conditions later in life.
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