Insulin-like growth factor 1 (IGF-1) was considered as a factor potentially involved in arterial hypertension because of its effects on vascular tone. Several studies have suggested that IGF-1 might play an important role in the cardiovascular system for regulation of blood pressure. Previously, microinjection of insulin into the NTS of rats preceded prominent depressor and bradycardic and activates the PI3K downstream Akt. The aims of this study was to compare the cardiovascular responses induced by IGF-1 and to investigate the mechanisms of IGF-1induced signaling pathway in the nucleus tractus solitarius (NTS) between spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto rat (WKY) at 8/16 weeks old. The results indicate that microinjection of IGF-1 into the NTS of WKY and SHR produced dramatically depressor and bradycardic effects. The cardiovascular effects evoked by IGF-1 are less in SHR than WKY rats. The defect in IGF-1 vascular action is also present in young spontaneously hypertensive rats (age 8 weeks). Pretreatment with the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 significantly attenuated the responses evoked by microinjection of IGF-1 in both SHR and WKY at 8/16 weeks old. Moreover, mitogen-activated protein kinase kinase (p44/p42MAPK) inhibitor PD98059 administration attenuated the cardiovascular effects of IGF-1 in WKY at 8/16 weeks old but had no effect in SHR at age matched. In conclusion, both IGF-1/PI3K and p44/p42MAPK signal transduction pathways are involved in controlling central cardiovascular effects in WKY, whereas PI3K but not p44/p42MAPK signaling pathway is involved in SHR. This different condition suggests that such insensitive pathway may play a causative role in the development of hypertension.

Chronic Intermittent Hypoxia (CIH) is a model used to study obstructive sleep apnea (OSA). Previously, we showed that baroreflex control of heart rate (HR) (baroreflex sensitivity) is reduced in CIH rats. While afferent function and HR in response to vagal efferent stimulation are enhanced, the effect of CIH on the central components, in particular NTS, is still not completely understood. F344 rats (3-4 mo) were exposed either to CIH or room air (RA) for 35-50 days. Following CIH exposure, rats were anaesthetized with Ket/Ace. Using single-unit extracellular recording technique, we recorded NTS barosensitive neurons in response to arterial pressure (AP) changes induced by descending aorta occlusion. Our data indicated that 1) the mean arterial pressure and HR were similar in RA control and CIH groups. 2) The majority of neurons from RA and CIH NTS neurons increased firing rate, whereas other neurons decreased firing upon AP elevation. 3) In 27 RA and 31 CIH NTS neurons with increased firing rate, 15 RA and 15 CIH neurons were activated at a low ?MAP at the early phase of AP increase (early neurons); whereas 12 RA neurons and 16 CIH neurons were activated at a late phase of AP increase (late neurons). The early neurons rapidly increased their firing during the rising phase of MAP, whereas late neurons did not increase their firing until the ?MAP reached its peak. 4) Early neuron activity-?MAP relationship was further characterized by the logistic sigmoid function curve. CIH significantly increased the maximal gain of the neuron activity-?MAP curve and the range of the response. In addition, CIH early neurons had a significantly higher firing rate than RA early neurons, whereas CIH did not change the firing rate in late neurons. 5) For late neurons, HR reduction correlated with neuronal activity. HR reduction-neuronal activity increase curve was shifted to the right in CIH neurons, indicating that CIH decreased HR control in response to NTS firing increase. Collectively, our data suggest that NTS barosensitive neurons have both early and late neurons, CIH selectively enhances neuron activity in response to AP changes in NTS early neurons and attenuate the baroreflex bradycardia. Along our previous work that CIH-induced the cell loss in the nucleus ambiguus (NA), we conclude that CIH attenuates the functions of NA, whereas enhances the NTS functions to compensate for the loss of function in NA

Abstract The phospholipid PI(3,4,5)P3 works as a second messenger in PI3K signaling pathway. The PI3K signaling pathway is involved in insulin stimulated nitric oxide (NO) production in vascular endothelium, leading to vasodilation and increased blood flow. However, the production of NO also has been reported in neurons as a neurotransmitter and in nucleus tractus solitarii (NTS), NO plays a role in central cardiovascular regulation. Previously, microinjection of insulin into the NTS of rats produces prominent depressor and bradycardic and activates the PI3K downstream Akt. Therefore, to investigate the detail downstream signaling of insulin stimulated NO production in NTS, the effects of PI(3,4,5)P3 on NO production were determined in neuronal cell lines PC12 and GH3 and in NTS of SD rats. The GH3 and differentiated PC12 exposed to 10

Vagal afferents form the primary gut-to-brain neural axis and are thought to communicate negative feedback signals to the central nervous system to attenuate consummatory behaviors by promoting satiation and possibly satiety. The expansive and fluid nature of the gastrointestinal organs has made it methodologically challenging to decipher the negative feedback signals, and how the signals are disseminated or converged within the central feeding systems. We sought to understand the anatomical relationship and organization between the terminal fields of the peripheral axonal projections and the central axonal projections of gastrointestinal (GI) vagal afferents for clues about what and how information is communicated along the gut-brain axis. Here, we quantified the density and distribution of peripheral and central GI vagal axonal projections in neurotrophin-4 deficient (KO) and control mice. KO mice exhibited a 75 and 55% reduction in small intestinal vagal mucosal afferents, proximally distally, and no significant reduction of mucosal vagal afferents in the stomach, compared to controls. Previous characterization, similarly, reported a >70% reduction in small intestinal vagal muscle afferents and no loss of muscle afferents in the stomach. Centrally, KO mice exhibited an increase in central terminal axonal projections in the medial nucleus tractus solitarius. Our findings support previous hypotheses that neurotrophin-4 exerts an organ-specific regulation of development of gastrointestinal vagal afferents innervation. Furthermore, our findings highlight the dynamic relationship between the peripheral and central axonal projections of vagal afferents.

No description available.

Orientador: Luciana Bolsoni Lourenço Morandini / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-20T20:53:49Z (GMT). No. of bitstreams: 1 Rodrigues_DeboraSilva_M.pdf: 3296545 bytes, checksum: 2a2ccc454f9a1df9f09173c2127af330 (MD5) Previous issue date: 2012 / Resumo: O gênero Engystomops apresenta ampla distribuição geográfica e constitui um interessante grupo de anuros para estudos cariotípicos. As populações de Engystomops encontradas na Amazônia têm sua identificação taxonômica ainda controversa. Análises genéticas e citogenéticas apoiam hipóteses que sugerem a existência de um complexo de espécies crípticas e especiação incipiente. Muitas vezes a variação citogenética observada entre diferentes populações estudadas dificultou o reconhecimento de homeologias cromossômicas entre os cariótipos. Uma caracterização cromossômica mais detalhada poderia auxiliar no possível reconhecimento de homeologias cromossômicas e, dessa forma, contribuir para o estudo dos processos envolvidos na divergência desses anuros. Já que o gene do DNAr 5S tem sido importante marcador genético e citogenético para estudos evolutivos e para a identificação e comparação de espécies em diversos grupos, no presente trabalho o DNAr 5S de Engystomops freibergi e de exemplares de Engystomops petersi de duas localidades Equatorianas (Puyo e Yasuní) foi estudado. Em todos os casos, dois tipos de DNAr 5S, facilmente diferenciados pelo tamanho e composição da sequência do seu espaçador não transcrito, foram isolados. A provável região promotora do gene do RNAr 5S (ICR) foi localizada nos dois tipos de sequências de DNAr 5S e a presença de possíveis sequências regulatórias adicionais foi discutida. No cariótipo de E. freibergi, sonda contendo a unidade repetitiva do DNAr 5S tipo I hibridou na região pericentromérica do braço curto dos cromossomos do par 3, e o DNAr 5S tipo II foi mapeado na região distal do braço longo dos cromossomos do par 6. A sonda formada somente pela região de NTS do DNAr 5S tipo I claramente detectou a região pericentromérica de 3p nos cariótipos de E. freibergi e E. petersi (Puyo) e de 5p no cariótipo de E. petersi (Yasuní), porém nenhum sinal distal ou intersticial foi observado. A sonda formada pela região de NTS do DNAr 5S tipo II detectou apenas a região distal de 6q nos três cariótipos estudados, corroborando a distribuição diferencial dos dois tipos de DNAr 5S nesses cariótipos. Tais sítios de DNAr 5S constituem novos marcadores cromossômicos, os quais permitem sugerir a homeologia entre o cromossomo 6 dos cariótipos de E. freibergi e de E. petersi, e entre o cromossomo 5 do cariótipo de E. petersi de Yasuní e o cromossomo 3 dos cariótipos de E freibergi e de E. petersi de Puyo. Já que os dois tipos de DNAr 5S encontrados em Engystomops são relacionados àqueles de Physalaemus tanto quanto à composição nucleotídica quanto à localização cromossômica, é ainda possível inferir que a origem desses dois tipos de sequências tenha antecedido a divergência evolutiva desses gêneros / Abstract: The Engystomops genus is widely distributed geographically and constitutes an interesting group for karyotypic studies. The taxonomic identifications of Amazonian populations of Engystomops is still controversial. Genetic and cytogenetic analyses suggest the existence of a complex of cryptic species and incipient speciation. The cytogenetic variations found among some populations prevent the recognition of chromosomal homeologies between the described karyotypes. A more detailed chromosomal characterization could help in the recognition of chromosome homeologies and, therefore, could contribute to the study of the processes involved in the divergence of these anurans. Since the 5S rDNA gene has been an important genetic and cytogenetic marker for evolutionary studies and even for the identification and comparison of species in diverse groups, in the present work the 5S rDNA of Engystomops freibergi and exemplars of Engystomops petersi from two Ecuadorian locations (Puyo and Yasuní) was studied. In all cases, two types of 5S rDNA, easily differed by size and compositon of their non-transcribed spacer, were isolated. A putative promoting region of the 5S rRNA gene (ICR) was recognized in the two types of 5S rDNA sequences and the presence of possible additional regulatory sequences was discussed. In the E. freibergi karyotypes, the entire type I 5S rDNA repeating unit hybridized to the pericentromeric region of 3p, whereas the entire type II 5S rDNA repeating unit mapped to the distal region of 6q, suggesting a differential localization of these sequences. The type I NTS probe clearly detected the 3p pericentromeric region in the karyotypes of E. freibergi and E. petersi from Puyo and the 5p pericentromeric region in the karyotype of E. petersi from Yasuní, but no distal or interstitial signals were observed. Interestingly, this probe also detected many centromeric regions in the three karyotypes, suggesting the presence of a satellite DNA family derived from 5S rDNA. The type II NTS probe detected only distal 6q regions in the three karyotypes, corroborating the differential distribution of the two types of 5S rDNA. Because the 5S rDNA types found in Engystomops are related to those of Physalaemus with respect to their nucleotide sequences and chromosomal locations, their origin likely preceded the evolutionary divergence of these genera. In addition, our data indicated homeology between chromosome 5 in E. petersi from Yasuní and chromosomes 3 in E. freibergi and E. petersi from Puyo. In addition, the chromosomal location of the type II 5S rDNA corroborates the hypothesis that the chromosomes 6 of E. petersi and E. freibergi are homeologous despite the great differences observed between the karyotypes of the Yasuní specimens and the others / Mestrado / Biologia Celular / Mestre em Biologia Celular e Estrutural

Ce travail s'inscrit dans le cadre général de l'étude des mécanismes d'intégration des informations viscérales. Nous avons étudié la dépression synaptique à long terme (DLT) dans le noyau du tractus solitaire et sa modulation par le statut nutritionnel Dans la première étude, nous avons caractérisé une DLT au niveau du NTS. Cette DLT, déclenchée par la stimulation des afférences viscérales à basse fréquence, est exprimée au niveau de l’élément présynaptique. Elle met en jeu une libération d'endocannabinoïdes qui en agissant au niveau de l’élément présynaptique réduisent la probabilité de libération de glutamate. De manière surprenante l’élément postsynaptique ne semble jouer aucun rôle dans cette DLT. Elle nécessite une activation séquentielle des récepteurs NMDA, la libération d'anandamide et l'activation des récepteurs aux cannabinoïdes de type 1 (CB1) et l’activité de l’élément présynaptique. Nos résultats suggèrent que cette DLT pourrait être entièrement organisée dans le compartiment présynaptique des afférences viscérales. Dans une deuxième partie du travail, nous nous sommes intéressés à la modulation de cette DLT dépendante des endocannabinoïdes (DLT-eCBs) par le statut nutritionnel. La privation de nourriture pendant 24 h empêche l'induction de la DLT-eCBs par la stimulation des afférences viscérales. Ces effets sont mimés par l'activation des récepteurs à la ghréline au niveau du NTS. Une re-nutrition pendant 3h restaure la DLT-eCBs via l'action périphérique de la Cholécystokinine (CCK) et l'activation de la voie ERK. Au total ces travaux soulignent la forte plasticité des afférences viscérales en fonction du statut nutritionnel. / This work joins within the framework of studies about the mechanisms of integration of the visceral informations. We studied long term synaptic depression in the nucleus of tractus solitarii (NTS) and it's modulation during changes in the nutritional status. In the first study, we characterized a long-term synaptic depression (LTD) in the NTS. This LTD, triggered by low frequency stimulation of visceral afferents is expressed at the presynaptic level. It involves release of endocannabinoids that would eventually reduce glutamate release probability. Surprisingly the postsynaptic element seems to play no role in this LTD. It requires sequential activation of NMDA receptors, the release of anandamide and activation of the cannabinoids type 1 receptors (CB1) and presynaptic activation. Our results suggest that this LTD could be entirely organized at the presynaptic compartment of visceral afferents. In the second part of this work, we were interested on the modulation of this endocannabinoïds dependent long-term depression (eCBs-LTD) by the nutritional status. Food deprivation during 24 h prevents the induction of eCBs-LTD by the stimulation of visceral afferents. These effects are mimicked by the activation of ghrelin receptors in the NTS. 3 h refeeding restores the eCBs-LTD via peripheral action of cholecystokinin (CCK) and the activation of the ERK pathway. Altogether, this work emphasizes the high plasticity of visceral afferents and its regulation by the nutritional status.

Epilepsy is a neurological disorder that is characterized by aberrant electrical activity in the brain resulting in at least two unprovoked seizures over a period longer than 24 hours. Approximately 60% of individuals with epilepsy are diagnosed with temporal lobe epilepsy (TLE) and about one third of those individuals do not respond well to anti-seizure medications. This places those individuals at high risk for sudden unexpected death in epilepsy (SUDEP). SUDEP is defined as when an individual with epilepsy, who is otherwise healthy, dies suddenly and unexpectedly for unknown reasons. SUDEP is one of the leading causes of death in individuals with acquired epilepsies (i.e. not due to genetic mutations), such as TLE. Previous studies utilizing genetic models of epilepsy have suggested that circuitry within the vagal complex of the brainstem may play a role in SUDEP risk. Gamma-aminobutyric acid (GABA) neurons of the nucleus tractus solitarius (NTS) within the vagal complex receive, filter, and modulate cardiorespiratory information from the vagus nerve. GABAergic NTS neurons then project to cardiac vagal motor neurons, eventually effecting parasympathetic output to the periphery. In this study, a mouse model of TLE was used to assess the effect of epileptogenesis on GABAergic NTS neuron function and determine if functional alterations in these neurons impact SUDEP risk. It was discovered that mice with TLE (i.e. TLE mice) have significantly increased mortality rates compared to control animals, suggesting that SUDEP occurs in this model. Using whole cell electrophysiology synaptic and intrinsic properties of GABAergic NTS neurons were investigated in TLE and control mice. Results suggest that during epileptogenesis, GABAergic NTS neurons become hyperexcitable, potentially due to a reduction in A-type potassium channel current and increased excitatory synaptic input. Increases in hyperexcitability have been shown to be associated with an increased risk of spreading depolarization and action potential inactivation leading to neuronal quiescence. This may lead to a decreased inhibition of parasympathetic tone, causing cardiorespiratory collapse and SUDEP in TLE.

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No. of bitstreams: 2 Dissertação - Stéfanne Madalena Marques - 2017.pdf: 2931392 bytes, checksum: 0d7549b7390188445fbcb19cb5e18723 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-17 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Several studies have determined the importance of intravenous infusion of sodium chloride (NaCl) solution in the cardiovascular recovery of hypovolemic hemorrhage (HH). Studies show the increased activity of the noradrenergic groups A1 and A2 in response to increased osmolarity in normovolemic rats. However, the participation of these neurons in the integration of the reflexive responses that lead to hemodynamic recovery and to the cardiovascular improvement induced by the infusion of hypertonic saline (HSI) solution during hypovolemia remain to be clarified. The present study sought to elucidate the participation of the noradrenergic groups A1 and A2 in cardiovascular recovery by HSI after HH in anesthetized rats. For this, mice should receive nanoinjections of 100 nL saporin (0.022 ng ∙ nl-1) or saporin-anti-DβH (0.105 ng ∙ nl-1) in the NTS region and/or bilaterally in the CVLM. After 20 days, the animals were instrumented to record the cardiovascular parameters: mean arterial pressure (MAP), heart rate (HR), renal vascular conductance (RVC), and aortic vascular conductance (AVC). HH was induced for 20 min by withdrawal of blood until a MAP reached about 60 mm Hg. Then, HIS (NaCl, 3M, 1.8 ml ∙ kg-1) / Diversos estudos determinaram a importância da infusão intravenosa de solução de cloreto de sódio (NaCl) hipertônica na recuperação cardiovascular da hemorragia hipovolêmica (HH). Estudos mostraram o aumento de atividade dos grupamentos noradrenérgicos bulbares A1 e A2 em resposta ao aumento da osmolaridade em ratos normovolêmicos. No entanto, a participação destes neurônios na integração das respostas reflexas que conduzem ao restabelecimento hemodinâmico e à melhora cardiovascular induzida pela infusão de solução salina hipertônica (SH) durante a hipovolemia ainda permanecem por ser esclarecidas. O presente estudo procurou elucidar a participação dos grupamentos noradrenérgicos bulbares A1 e A2 na recuperação cardiovascular por infusão de SH após HH em ratos anestesiados. Para isto, ratos Wistar receberam nanoinjeções de 100 nL de saporina (0,022 ng ∙ nl-1) ou saporina-anti-DβH (0,105 ng ∙ nl-1) na região NTS e/ou bilateralmente no CVLM. Após 15 dias, os animais foram instrumentalizados para registro dos parâmetros cardiovasculares: pressão arterial média (PAM), frequência cardíaca (FC), condutância vascular renal (CVR) e condutância vascular aórtica (CVA). A HH foi induzida durante 20 min pela retirada de sangue até que a PAM atingisse aproximadamente 60 mmHg. Em seguida, foi realizada a administração de solução SH (NaCl; 3M; 1,8 ml ∙ kg-1), e os parâmetros cardiovasculares foram registrados por mais 60 min. Os resultados mostraram que, nos animais com lesão do grupamento A2, após a infusão de SH a PAM retornou aos valores basais de maneira similar ao que ocorreu nos animais controle (sham A2: 109,4 ± 3,7 mmHg vs. Lesão A2: 108,6 ± 5,1 mmHg, 60 min após a infusão de SH); a FC reduziu significativamente em ratos controle e com lesão de A2 durante a HH e retornou aos níveis basais 10 min após infusão de SH (controle A2: 406,0 ± 10,6 bpm vs. Lesão A2: 368.8.1 ± 17,9 bpm); a HH e a infusão de solução SH não promoveu alterações nos valores basais de CVR em ambos os grupos (sham A2: Δ 3,0 ± 22,3%; Lesão A2: Δ -23,5 ± 16,6%, 20 min após a HH) e (sham A2: Δ 2,3 ± 18,8 vs. Lesão A2: Δ 7,3 ± 8,3%; 30 min após a infusão de SH). A CVA não foi alterada pela HH (sham A2: Δ -11,1 ± 6,6% vs Lesão A2: Δ 7,8 ± 11,6%; 20 min após a HH) ou infusão de SH (Sham: Δ -20,6 ± 7,8% vs. Lesão A2: Δ -4,4 ± 5,1%, 30 min após a infusão de SH). Nos animais com lesão combinada dos grupamentos A1 e A2, a infusão de SH não reestabeleceu os níveis de PAM (controle A1+A2: 104,9 ± 5,7 vs Lesão A1+A2: 64,2 ± 4,5 mmHg; p <0,05; 30 min após a infusão SH), permanecendo estes em níveis hemorrágicos até o final dos experimentos (controle A1+A2: 107,1 ± 3,3 vs Lesão A1+A2: 68,4 ± 4,2 mmHg; p <0,05; 60 min após infusão SH). A HH não alterou os valores basais de CVR (Sham A1+A2: Δ 4,7 ± 20,2% vs. Lesão A1+A2: Δ 2,9 ± 16,7%; 20 min após a HH); a solução SH, também, não foi capaz de alterar esse parâmetro nos grupos de animais controle e lesado (sham A1+A2: Δ: 0,1 ± 12,1% vs. Lesão A1+A2: Δ 29,4 ± 25,9%; 30 min após a infusão de SH). No grupo submetido a lesão A1+A2, a CVA não foi alterada pela HH em ambos os grupos (sham A1+A2: Δ -1,5 ± 16.3% vs. Lesão A1+A2: Δ -18,6 ± 6,3%; 20 min após a HH) ou pela infusão de solução de SH (sham A1+A2: Δ 20 ± 117% vs. Lesão A1+A2: Δ 9,5 ± 7,7%; 30 min após a infusão de SH). Os resultados indicam que o grupamento neuronal A2 não parece estar diretamente envolvido na recuperação cardiovascular por infusão de SH em ratos submetidos a HH e que a lesão simultânea dos grupamentos A1 e A2 foi capaz de suprimir a restauração da PAM em resposta à SH após a HH, indicando que a integridade desses grupamentos é essencial para a recuperação cardiovascular mediante hipernatremia aguda após a hipovolemia. Nosso estudo indica ainda que esses grupamentos não parecem estar diretamente envolvidos na regulação da reatividade vascular dos leitos analisados.

Tunnel safety – an inventory of accidents in four road tunnels in Stockholm This report investigates traffic accidents in four road tunnels in Stockholm. The tunnels investigated are Klaratunneln, Söderledstunneln, Törnskogstunneln and Häggvikstunneln. The main purpose of this project was to work with a delimited part of the project TUFS (Tunnel Framkomlighet och Säkerhet, Tunnel practicability and safety, my translation) that is going to build a knowledge bank for Swedish road tunnel accidents. The goal of this project was to investigate if the forecasts for accident rates in the tunnels calculated from empirical data differ from the forecasts of the road network made by the forecast program used by Trafikverket, Lill-EVA, for the observed tunnels. Another goal was to determine where accidents occur in the tunnels. In addition, two different tunnel types were compared in terms of accident rates. The tunnel types are located in: countryside (high speed, low traffic flows, no on- and off ramps) or urban center (low speed, high traffic flows, on- and off ramps). Accident data has been collected from the data bases STRADA and NTS and compiled in histograms displaying accident type, light conditions, the seriousness of the accident and number of accidents/year. The results showed that there are no differences in accident rates calculated by Lill-EVA and empirical data for accident rate, serious accident rate and death rate. However, there was a difference in the results concerning light injuries. No difference was found regarding the two tunnel types. Rear-end collision was the most common accident type in Söderledstunneln and serial vehicle crashes in Törnskogstunneln and Häggvikstunneln. Vehicles that got stuck in the tunnel entrance dominated the accident type in Klaratunneln. The majority of the accidents occurred in daylight. The coordinate positions for the accidents showed that there was a concentration of accidents near the tunnel entrance in Klaratunneln, Söderledstunneln and Häggvikstunneln. This is not the case for Törnskogstunneln where accidents have occurred in the tunnel center.