Au sein du laboratoire, deux mécanismes neurovasculaires indispensables à l’intégrité fonctionnelle de la peau sont étudiés. La PIV (Pressure-Induced vasodilation) est un mécanisme protecteur qui permet de retarder l'ischémie tissulaire. Des études antérieures ont suggéré l’implication du système nerveux central dans ce mécanisme. La première partie de ma thèse était de préciser le contrôle spinal dans la PIV et de regarder si la perte de ce mécanisme protecteur augmente le risque d’escarres. Nous avons montré l’implication de la voie sensorielle spinale dans la PIV ainsi que la corrélation directe entre la perte de ce mécanisme et l’augmentation du risque d’escarres chez des animaux sains. La CIV (current-induced vasodilation) a été décrite comme étant un mécanisme neurovasculaire de type « réflexe d'axone ». Exclusivement étudiée chez l’homme, les mécanismes impliqués restent limités. La seconde partie de ma thèse était de développer un modèle animal et approfondir la compréhension des mécanismes sous-jacents de la CIV cathodale. Après avoir développé un modèle animal, nous avons prouvé l’implication de la voie COX1/PGIS/PGI2/IP, des TRPV1 et des ASIC cutanés présents sur les fibres capsaïcino-sensibles ainsi que celles des récepteurs aux CGRP et à la substance P dans la CIV cathodale chez le rat sain. Pour conclure, la PIV est un outil diagnostique intéressant pour évaluer les capacités protectrices de la peau contre les lésions ischémiques de pression en conditions physiologiques. La CIV reflète de la libération endogène de PGI2 dans la peau, offrant un outil complémentaire à la réponse à l’acétylcholine afin d’évaluer les capacités globales de l’endothélium / In our lab, two neurovascular mechanisms required for functional integrity of the skin are studied. The pressure-Induced vasodilation (PIV) is a protective mechanism, which delays the occurrence of tissue ischemia likely protecting the skin against pressure. Previous studies suggested the contribution of the central nervous system in this mechanism. In the first part of my PhD, we studied the spinal sensory transduction involvement in PIV and verify whether the lack of PIV increased incidence of pressure-induced ischemic lesions in healthy rats. We showed that spinal sensory disruption led to the loss of cutaneous PIV directly associated with increased incidence and severity of cutaneous lesions in response to prolonged ischemic compression in healthy animals. The current-induced vasodilation (CIV) is a neurovascular mechanism decribed as axon reflex mechanism. Exclusively studied in humans, the understanding of involved mechanisms remains limited. In the second part of my PhD, we aimed to develop an animal model and precise the underlying mechanisms involved in cathodal CIV. That we developed, we proved the involvement of the COX1/PGIS/PGI2/IP pathway, the cutaneous TRPV1 and ASIC channels present on capsaicin-sensitive fibres and the cutaneous CGRP and NK1 receptors in cathodal CIV in healthy rats. To conclude, PIV is an interesting tool to evaluate the protective capacities of the skin to withstand pressure in healthy conditions. CIV by reflecting the endogenous release of PGI2 in healthy skin offers a novel tool in complement to acetylcholine response in order to assess global capacities of the endothelium

<p>In birds like the Zebra finch (Taeniopygia guttata) the female, but not the male develop a brood patch upon incubation of eggs. The brood patch functions to increase heat exchange between the bird and the eggs. Development of the brood patch includes de-feathering, increased vascularization and edema formation. The increased vascularization is due to the development of arteriovenous anastomoses, AVA. The AVA are thermoregulatory vessels involved in cold induced vasodilation, CIVD, demonstrated to occur in the brood patch. Nitric oxide, NO, which is a well known vasodilator is a candidate substance for involvement in CIVD. In this study a NO-generating gel was applied to the brood patch of male and female zebra finches. Vasodilation was found to be markedly larger in females than in males. The larger vasodilation in the female brood patch is probably because NO vasodilate AVA selectively more than any other vessels. The study also investigated whether vasodilation would cause an increase in brood patch temperature. No definite changes in brood patch temperature could be observed and no conclusions could be drawn in the matter.</p>

A disfunção endotelial atua tanto na aterogênese como na precipitação das síndromes coronárias agudas. A redução da biodisponibilidadedo óxido nítrico é expressão de endotélio disfuncional. O mecanismo desta redução não está elucidado. A presença de disfunção endotelialfoi correlacionada com fatores de risco (FR), nitrato sanguíneo e fatores genéticos (polimorfismo da óxido nítrico sintase endotelial, fibrinogênio e PAI-1) em um grupo de 128 pacientes com infarto do miocárdio (IAM) e idade = 40 anos, submetidos a ultra-som de artéria braquial. Os resultados foram comparados com um grupo jovens saudáveis. Verificou-se que pacientes jovens com IAM apresentavam disfunção endotelial em associação com FR, alterações bioquímicas e níveis aumentados de nitrato, porém sem alterações genéticas / The endothelial dysfunction plays an important roll in the atherogenesis and precipitation of acute coronary syndromes. The reduction of bioavailability of the nitric oxide is the expression of endothelial dysfunction. The exact mechanism of this reduction is not yet well explained. In order to evaluate the presence of endothelial dysfunction and correlation with risk factors (FR), nitrate blood levels and genetic factors (endothelial nitric oxide synthease polymorphism, fibrinogen and PAI-1) a 128 myocardial infarction patients group with age = 40 year was studied, and underwent a brachial artery ultra-sound. The results were compared with a group of young health individuals. The study found that the young patients with myocardial infarctions showed endothelial dysfunction with associated risks factors, biochemical changes and higher levels of nitrate, although without any significant genetic changes

Master of Science / Department of Kinesiology / Timothy I. Musch / Both cardiac and peripheral vasculature dysfunction likely contribute, in part, to elevations in TNF-[alpha] and exercise intolerance in chronic heart failure (CHF). The pharmaceutical TNF-[alpha] synthesis suppressor pentoxifylline (PTX) reduces plasma [TNF-[alpha]] and improves left ventricular (LV) function in CHF rats, but the effects of PTX on skeletal muscle blood flow (BF) and vascular conductance (VC) during exercise are unknown. We tested the hypothesis that PTX would elevate skeletal muscle BF and VC at rest and during submaximal treadmill exercise in CHF rats (coronary artery ligation). CHF rats received i.p. injections of 30 mg·kg[superscript]-[superscript]1·day[superscript]-[superscript]1 of PTX (CHF+PTX, n=13) or saline (CHF, n=8) for 21 days. Mean arterial pressure (MAP) and BF (radiolabeled microsphere infusions) were measured at rest and during treadmill exercise (20 m/min, 5% grade). Myocardial infarct (MI) size was not different between groups (CHF: 37±4, CHF+PTX: 37±3% of LV wall; p>0.05). Resting and exercising MAP was greater in CHF+PTX compared to CHF (p<0.05 for both). At rest, total hindlimb skeletal muscle BF and VC were not different between groups (p>0.05). However, during exercise PTX increased total hindlimb BF (CHF: 83±9, CHF+PTX: 114±8 ml·min[superscript]-[superscript]1·100g[superscript]-[superscript]1, p<0.05) and VC (CHF: 0.75±0.08, CHF+PTX: 0.88±0.06 ml·min[superscript]-[superscript]1·100g[superscript]-[superscript]1·mmHg[superscript]-[superscript]1, p<0.05). Furthermore, exercising BF was increased in 21, and VC in 11, of the 28 individual hindlimb muscles or muscle parts with no apparent fiber-type specificity. Thus, PTX administration augments skeletal muscle BF and VC during locomotory exercise in CHF rats, which carries important therapeutic implications for CHF patients.

Master of Science / Department of Kinesiology / B.J. Wong / Recent data suggests nNOS mediates the NO-component of reflex cutaneous vasodilation with passive heat stress. Our hypothesis was nNOS, but not eNOS, inhibition would attenuate reflex cutaneous vasodilation during dynamic exercise. Protocol 1: subjects performed a VO[subscript]2 peak test on a supine cycle ergometer. Protocol 2: with experimental arm at heart level subjects cycled in supine posture at 60% VO[subscript]2 peak to raise core temperature (Tc) 0.8-1.0°C (35-45 min). In protocol 2 subjects were equipped with 4 microdialysis fibers on the forearm and each randomly assigned as: 1) lactated Ringer’s (control); 2) 5mM NPLA (nNOS inhibition); 3) 10mM L-NIO (eNOS inhibition); and 4) 20mM L-NAME (non- selective NOS inhibition). At the end of protocol 2 all sites were locally heated to 43°C and infused with SNP to elicit maximal dilation. Mean arterial pressure (MAP), skin blood flow via laser- Doppler flowmetry (LDF), and Tc via ingestible telemetric pill were measured; cutaneous vascular conductance (CVC) was calculated as LDF/MAP and normalized to maximum. In protocol 2 there was no significant difference between control (62±5 %CVCmax) and NPLA (61±6 %CVCmax). L-NIO (38±4 %CVCmax) and L-NAME (41±7 %CVCmax) significantly attenuated CVC compared to control and NPLA (p<0.001 all conditions). There was no difference between L-NIO and L- NAME. We conclude eNOS, not nNOS, contributes to reflex cutaneous vasodilation during dynamic exercise.

O presente estudo avaliou o efeito do exercício físico aeróbico na função vasomotora dependente do endotélio em aorta de ratos bem como os mecanismos envolvidos na regulação da biodisponibilidade do NO. Para tanto, um grupo de animais foi submetido a uma sessão de exercício (EX, n=17) enquanto o outro grupo permaneceu em repouso (CT, n=18). Imediatamente após o exercício, os ratos de ambos os grupos foram eutanasiados para a retirada da aorta torácica para análises funcionais e bioquímicas. Resultados: observamos que o grupo exercitado apresentou uma melhora no relaxamento dependente do endotélio com um efeito máximo de 12%, sendo esse efeito relacionado a um aumento na ativação da eNOS. Apesar de aumentar o NO, os animais do grupo EX apresentaram níveis aumentados de superóxido (28%), efeito que foi associado à maior ativação do complexo enzimático NAD(P)H oxidase. Além do superóxido, o peróxido de hidrogênio também foi aumentado nos animais exercitados porém a maior produção de espécies reativas de oxigênio não foi suficiente para causar um estresse oxidativo vascular. Esses resultados demonstram que uma única sessão de exercício físico aeróbico é capaz de melhorar a vasodilatação dependente do endotélio por aumentar a biodisponibilidade de NO e que a produção de espécies reativas oxigênio também aumenta porém em níveis controlados . / The present study evaluated the effect of aerobic physical exercise on endothelium-dependent vasomotor function of rat aorta as well the mechanisms involved in nitric oxide bioavalability control. One group of rats was submitted to one bout of exercise (EX, n=17) while the other one was placed on the treadmill without running (CT, n=18). Immediately after exercise both group were sacrificed and the thoracic aorta was removed for functional and biochemical analysis. Results: we observed that EX group showed an improvement on endothelium-dependent relaxation (12%) and it was related to increase on eNOS activation. Despite increased nitric oxide levels, EX group demonstrated higher superoxide production (28%) that was associated to NAD(P)H oxidase activation. Additionally, hydrogen peroxide also increased in EX group but the increase in reactive oxygen species was not enough to cause oxidative stress. Theses results demonstrate that one bout of aerobic exercise can improve endothelium-dependent vasodilation by increasing NO bioavalability, and that reactive oxygen species also increases but in a controlled fashion

Made available in DSpace on 2017-07-21T14:13:13Z (GMT). No. of bitstreams: 1 Luiz Renato Olchanheski Junior.pdf: 1811415 bytes, checksum: 57ce362be4cfc124e9a1788156185688 (MD5) Previous issue date: 2014-02-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Periodontitis is defined as a disease characterized by the formation of a biofilm which promotes colonization of microorganisms responsible for the initiation of a local inflammatory process. Studies have shown that the inflammatory process is not restricted to the oral cavity, reaching the circulation and causing systemic effects, such as endothelial dysfunction. The dysfunction is mainly characterized by reduced nitric oxide production/ bioavailability which increased platelet aggregation, leukocyte adhesion and rolling, and result in a loss in the ability of vasodilation. Therefore predisposing to an increased risk of cardiovascular disease. According to research by our group, animals with experimental periodontitis showed a decrease in endothelium-dependent vasodilator response fourteen days after the induction of periodontitis, however, this reduced vasodilator response is not evident twenty one days. The purpose of this study was to evaluate a possible increase in compensatory mechanisms of vasodilation in animals with experimental periodontitis. For this, rats received ligatures for induction of periodontitis, or were sham. Twenty one days after the procedure, the animals were prepared for blood pressure recording. Two consecutive dose-response curves to acetylcholine and sodium nitroprusside were obtained before and 20 min after LNAME (NOS inhibitor) + indometacin (COX inhibitor) + TEA (selective inhibitor of potassium channels) or LNAME or indometacin, or TEA or indometacin + TEA or Apamin + TRAM-34 injection. Only the selective and simultaneous blockade of small and intermediate-conductance calcium-activated potassium channels by selective inhibitors (Apamin and TRAM-34, respectively) was able to reduce acethylcholine-induced reduction on blood pressure at periodontitis animals. The inhibition of NOS, COX and use of a non-selective inhibitor of potassium channels, did not change the endothelium-depended vasodilatation. Altogether, these results show that IKca and SKca may balance the endothelial function and therefore mask the impairment on NO production and endothelial dysfunction. / A periodontite é definida como uma doença caracterizada pela formação de um biofilme dental, que favorece a colonização de microrganismos que iniciam um processo inflamatório local. Este processo inflamatório não fica restrito a cavidade bucal, ele ganha a circulação causando efeitos sistêmicos, como a disfunção endotelial. A disfunção é caracterizada principalmente pela redução da produção e biodisponibilidade de óxido nítrico, predispondo o indivíduo a um aumento no risco de doenças cardiovasculares. Trabalhos recentes mostram que animais com periodontite experimental apresentam uma disfunção endotelial quatorze dias após a indução da periodontite, porém, esta redução da resposta vasodilatadora não é evidente vinte e um dias após o mesmo procedimento. A proposta do presente trabalho foi avaliar um possível aumento de mecanismos compensatórios de vasodilatação em animais com periodontite experimental. Para isso, os ratos receberam as ligaduras para indução da periodontite, ou passaram pela falsa-cirurgia. Vinte e um dias após o procedimento, todos os animais passaram pela administração intravenosa de três doses crescentes de acetilcolina e nitroprussiato de sódio. Em seguida, os animais receberam as seguintes administrações: LNAME (inibidor da NOS) + indometacina (inibidor da COX) + TEA (inibidor não seletivo dos canais de potássio), ou LNAME, ou indometacina, ou TEA, ou administração de indometacina + TEA ou Apamina (inibidor seletivo dos SKCa) + TRAM-34 (inibidor seletivo dos IKCa). Após um período de 20 minutos, todos os grupos passaram por uma nova administração dos dois agentes vasodilatadores. Vinte e um dias após a indução da periodontite, os animais, não apresentaram disfunção, e a inibição de NOS, COX e a utilização de um inibidor não seletivo dos canais de potássio, evidenciou uma alteração no tempo de vasodilatação do grupo ligadura. A combinação dos demais inibidores não resultou em alterações significativas. A administração de inibidores de SKCa e IK Ca resultou em uma diminuição do tempo da resposta vasodilatadora dependente de endotélio, demonstrando a importância destes canais no mecanismo de compensação vasodilatadora 21 dias após a indução da doença periodontal.

Ng Chau Wah Stephen. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 120-135). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.viii / Publications --- p.ix / Abbreviations --- p.x / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Traditional Chinese Medicine --- p.1 / Chapter 1.2 --- Danshen --- p.7 / Chapter 1.2.1 --- Chemical constituents of Danshen --- p.7 / Chapter 1.2.2 --- Pharmacology of Danshen --- p.10 / Chapter 1.3 --- Vascular system --- p.13 / Chapter 1.3.1 --- Physiology of blood vessels --- p.13 / Chapter 1.3.2 --- Vascular smooth muscle contraction --- p.14 / Chapter 1.3.3 --- Mechanism of vascular smooth muscle contraction --- p.15 / Chapter 1.3.3.1 --- Adrenoceptor in vascular system --- p.19 / Chapter 1.3.3.2 --- Muscarinic receptor in vascular system --- p.20 / Chapter 1.3.3.3 --- Synthesis and release of Nitric Oxide (NO)in vascular system --- p.22 / Chapter 1.3.3.4 --- Synthesis and release of postanoidsin vascular system --- p.25 / Chapter 1.3.3.5 --- Synthesis and release of histaminein vascular system --- p.28 / Chapter 1.3.3.6 --- Synthesis and release of Calcitonin gene-related peptide in vascular system --- p.29 / Chapter 1.4 --- Aims of the studies --- p.33 / Chapter Chapter 2 --- Materials and methods / Chapter 2.1 --- Materials --- p.35 / Chapter 2.2 --- Methods - General procedures --- p.35 / Chapter 2.2.1 --- Preparations of drug solutions --- p.35 / Chapter 2.2.2 --- Animals used and anaesthetization --- p.36 / Chapter 2.2.3 --- Cannulation of carotid artery and jugular vein --- p.37 / Chapter 2.2.4 --- Blood pressure measurement --- p.37 / Chapter 2.2.5 --- Knee joint denervation --- p.38 / Chapter 2.2.6 --- Knee joint blood flow measurement --- p.39 / Chapter 2.3 --- Methods - Specific procedures --- p.41 / Chapter 2.3.1 --- Validation of Laser Doppler Imaging (LDI) measurements --- p.41 / Chapter 2.3.2 --- Actions of topical administration of Danshen --- p.42 / Chapter 2.3.2.1 --- Studies of the mechanism(s) of action of Danshen --- p.43 / Chapter 2.3.2.2 --- Investigation for α-adrenoceptor antagonist activity --- p.44 / Chapter 2.3.2.3 --- Investigation for neural involvement --- p.44 / Chapter 2.3.3 --- Actions of intravenous administration of Danshen --- p.45 / Chapter 2.3.4 --- Data analysis --- p.45 / Chapter Chapter 3 --- Results / Chapter 3.1 --- Validation of LDI measurement --- p.47 / Chapter 3.2 --- Actions of intravenous administration of Danshen --- p.53 / Chapter 3.3 --- Actions of topical administration of Danshen --- p.53 / Chapter 3.4 --- Muscarinic receptor antagonist on Danshen --- p.61 / Chapter 3.5 --- β-adrenoceptor antagonist on Danshen --- p.67 / Chapter 3.6 --- Danshen on α-adrenoceptor agonist-induced vasoconstriction --- p.74 / Chapter 3.7 --- Nitric oxide synthase inhibitor on Danshen --- p.79 / Chapter 3.8 --- Cyclo-oxygenase (COX) inhibitor on Danshen --- p.83 / Chapter 3.9 --- Histamine receptor antagonists on Danshen --- p.87 / Chapter 3.10 --- CGRP receptor antagonist on Danshen --- p.92 / Chapter 3.11 --- Effect of denervation on Danshen --- p.92 / Chapter Chapter 4 --- Discussion --- p.100 / Reference --- p.120

"2+" in the title is superscript. / "December 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 179-204) / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Orientador: Carlos Alberto Hussni / Resumo: A venografia é um exame radiográfico contrastado utilizado para identificar ou avaliar a função venosa de membros, órgãos ou região anatômica. A lidocaína é um anestésico local que possui efeito vasodilatador. O objetivo do trabalho foi avaliar o efeito da lidocaína (2%), na venografia distal do membro torácico de equinos hígidos, por meio da descrição e contagem dos vasos contrastados distalmente ao membro, comparou-se a aplicação de 40 mL de contraste diatrizoato de meglumina 60% associado à lidocaína 2% com a associação de solução salina 0,9% e os volumes entre 40 e 60 mL de solução, questionando-se se a variação de volume ou a associação com a lidocaína pela vasodilatação podem diferir sobre no preenchimento venoso. Em cinco equinos adultos hígidos procedeu-se a venografia em ambos os membros torácicos com estase a partir de torniquete aplicado na região distal do rádio, aplicando-se para cada membro torácico os protocolos 40S (20 mL de meio de contraste + 20 mL de solução salina 0,9%), 40L (20 mL de meio de contraste + 20 mL de lidocaína 2%) e 60S (30 mL de meio de contraste + 30 mL de solução salina 0,9%) com intervalo de cinco dias entre cada exame. Os exames radiográficos foram realizados nas projeções dorso-palmar (DPa) e látero-medial (LM) (70 kV, 8 mAs e 70 cm distância foco-filme). As medianas foram calculadas a partir da contagem de vasos nas duas posições radiográficas e nas regiões distal de metacarpo e média das falanges proximal e média. Foi observado a distr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Venography is a contrasted radiographic examination used to identify or evaluate venous function in limbs, organs or other anatomic regions. Lidocaine is a local anesthetic that has a vasodilator effect. The aim of this study was to evaluate the effect of lidocaine (2%), in the distal venography of the distal forelimb of horses, through the description and counting of regional distal vessels, comparing the application of contrast solution associated with lidocaine and saline solution in total volumes of 40 or 60 mL, aiming to evaluate whether the volume variation or the association with lidocaine would interfere in the results. Venography was performed on both forelimbs of five adult horses, with stasis from a tourniquet applied to the distal radius, applying three different combinations of fluids: group 40S received 20 mL of contrast + 20 mL of saline solution 0,9%; group 40L received 20 mL of contrast + 20 mL of lidocaine 2% and group 60S received 30 mL de contrast + 30 mL of solution saline 0,9%. An interval of five days between every utilization was respected. The radiographs were made in the dorsopalmar and lateromedial projections (70kV, 8 mA and 70 cm of distance). The medians were calculated using the vessel count of both radiographic projections, in the distal metacarpal and middle regions of the proximal and middle phalanges. Axial distribution to the distal phalanx was observed in all protocols, with more evidence of the larger caliber of the vessels when lidocaine... (Complete abstract click electronic access below) / Mestre