Made available in DSpace on 2015-05-14T12:59:30Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3470014 bytes, checksum: ec4369a3d6de32a48a92ee347d505698 (MD5) Previous issue date: 2011-11-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Several epidemiological studies indicated that regular intake of red wine is associated with a decrease global mortality. The protective effect has been attributable, at least in part, to polyphenols. The cardiovascular effects induced by lyophilized red wine from Vale do São Francisco (LVTVSF) were evaluated in this study using in vivo and in vitro assays. The lyophilized red wine from Vale do São Francisco (LVTVSF) contains a series of flavonols, such, quercetin, myricetin and kaempferol. The red wine lyophilized was able to reduce mean arterial pressure (MAP) in L-NAME hypertensive rats compared to controls (143.7 ± 4.7 versus 172.5 ± 4.7 mmHg). In normotensive rats the administration of LVTVSF (10, 30, 90 mg/kg i.v.) randomly, induced hypotension (-24.0 ± 1.2; -32.4 ± 1.3; -51.4 ± 1.5%) and tachycardic effects (14.5 ± 2.3; 19.5 ± 1.7; 28.4 ± 2.1%). The pre-treatment with L-NAME (20 mg / kg i.v.), inhibitor of endothelial nitric oxide synthase, attenuated the hypotensive effect induced by LVTVSF. In isolated normotensive rat mesenteric artery rings LVTVSF elicited concentration-dependent relaxation of PHE-induced contraction (MR = 87.22 ± 3.59%). After removal of the vascular endothelial the vasorelaxant effect was significantly attenuated (MR = 32.07 ± 2.07%, p < 0.05), suggesting the involvement of endothelium-derived relaxing factor. After incubation with L-NAME (100 μM) and ODQ (10 mM), inhibitor of soluble guanylyl cyclase, the relaxation response was significantly attenuated (MR= 22.64 ± 3.74%, p < 0.05; MR = 37.08 ± 4.60%, p < 0.05, respectively). Similar results was also obtained rings incubed with KCl (20 mM), a modulator of potassium efflux; TEA (1 mM), nonselective blocker for potassium channels; (MR = 46.04 ± 9.87%, p < 0,05; MR = 44.40 ± 5.80%, p < 0,05; respectively). The LVTVSF was able to increase the NO levels in endothelial cells of the rabbit aorta. In the presence of charybdotoxin and apamin the relaxant response was not attenuated. Incubation with inhibitors of reactive oxygen species, N-acetylcysteine (NAC) (10 mM), tempol (100 μM) and apocynin (10 μM), reduces the vasorelaxation. After pre-treatment with atropine and indometacin, the vasorelaxant effect induced by LVTVSF was no attenuated. In endothelial cells of the rabbit aorta LVTVSF was able to increase production of ROS. These results together suggest that the hypotensive effect induced by LVTVSF in normotensive rats is probably due to a decrease in total peripheral resistance as a result of activation of the eNOS-NO-cGMP, involving the redox sensitive mechanism. These effects may be due to flavonoids found in LVTVSF. / Estudos epidemiológicos demonstram que o consumo regular de vinho está associado a um decréscimo da mortalidade global. Acredita-se que o efeito protetor seja decorrente, pelo menos em parte, da presença de polifenóis. A atividade biológica do Liofilizado do vinho tinto do Vale do São Francisco (LVTVSF) foi estudada no sistema cardiovascular usando técnicas combinadas in vivo e in vitro. A análise química do LVTVSF revelou a presença de vários polifenóis, como a quercetina, miricetina e caempferol. Em ratos com hipertensão induzida pelo L-NAME, o LVTVSF foi capaz de reduzir a pressão arterial média (PAM) quando comparado ao grupo controle (143,7 ± 4,7 versus 172,5 ± 4,7 mmHg), sem alterar a frequência cardíaca (FC). Ratos normotensos no qual foi administrado LVTVSF (10, 30, 90 mg/Kg i.v) aleatoriamente promoveu efeitos hipotensor (-24,0 ± 1,2; -32,4 ± 1,3; -51,4 ± 1,5 %),) e taquicárdico (14,5 ± 2,3; 19,5 ± 1,7; 28,4 ± 2,1%). A resposta hipotensora foi significantemente atenuada após a administração de NG-nitro- L-arginina-metil-éster (L-NAME) (20 mg/Kg i.v.), um inibidor da enzima sintase de óxido nítrico. Em preparações com anéis de artéria mesentérica superior isolada de ratos normotensos pré-contraídos com fenilefrina, o LVTVSF promoveu um efeito vasorelaxante (Emax= 87,22 ± 3,59%). Após a remoção do endotélio vascular o vasorelaxamento foi significativamente atenuado (Emax= 32,07 ± 2,07%, p < 0,05), sugerindo a participação de fatores relaxantes derivados do endotélio. Após a incubação com L-NAME (100 μM) e ODQ (10 μM), um inibidor da ciclase de guanilil solúvel, a resposta relaxante do composto foi significantemente atenuada (Emax.= 22,64 ± 3,74%, p < 0,05 e Emax= 37,08 ± 4,60%, p < 0,05, respectivamente). Resultados similares também foram obtidos em anéis com endotélio, na presença de KCl (20 mM), modulador do efluxo de K+; ou TEA ( 1mM), bloqueador não seletivo dos canais de K+; (Emax= 46,04 ± 9,87%, p < 0,05) e (Emax= 44,40 ± 5,80% p < 0,05). O LVTVSF aumentou os níveis de óxido nítrico em células endoteliais de aorta de coelho. Na presença de caribdotoxina (0,2 μM) e apamina (0,2 μM), bloqueadores dos canais de K+ sensiveis ao cálcio, o efeito relaxante induzido por LVTVSF não foi alterado. A incubação com os inibidores de espécies reativas de oxigênio, n-acetilcisteína (10 mM), tempol (100 μM) e apocinina (10 μM), diminuíram o vasorelaxamento. O efeito vasorelaxante não foi alterado na presença de atropina e indometacina, sugerindo que receptores muscarínicos, bem como metabólitos da via do ácido araquidônico não estão envolvidos neste efeito. Em células endoteliais de aorta de coelho o LVTVSF foi capaz de aumentar a produção de espécies reativas de oxigênio (ROS). Esses resultados em conjunto sugerem que o efeito hipotensor induzido por LVTVSF provavelmente ocorre devido à redução na resistência periférica total, resultado da ativação da via eNOS-NO-GMPc, envolvendo um mecanismo sensível a sinalização redox. Esses efeitos podem ser atribuídos aos flavonóides encontrados no LVTVSF.

Made available in DSpace on 2015-05-14T12:59:37Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1885626 bytes, checksum: ba22595f4724b5f41ad1ed2a1d361360 (MD5) Previous issue date: 2012-02-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The aim of the present study was to evaluate the cardiovascular effects of Garziera red wine (Shiraz grape, vintage 2005) (GASH) of the Vale do São Francisco (Pernambuco Brazil) by using in vitro and in vivo approaches. Measurements of polyphenols levels in GASH revealed high levels of total phenolics compounds, quercetin and cis- and trans-resveratrol. Acute toxicity tests showed that GASH presented toxic effects only at doses 10-fold higher than the doses used in the in vivo experiments. Oral treatment with GASH at dose of 100 mg/kg/day for 7 days in normotensive rats did not promote significant differences in MAP and HR group treated with GASH (mmHg= 119.0 ± 2.02) compared to the control group (mmHg= 120.20 ± 2.04). In nonanesthetized SHR rats treated orally with GASH for 21 days at dose of 100 mg/kg/day, GASH decreased the MAP in the group treated (mmHg= 122.7 ± 1.52) compared to the control group (mmHg= 156.0 ± 5.39) and there was no change in HR. Similar results occurred with SHR rats and L-NAME hypertensive rats treated with GASH at dose of 100 mg/kg/day for 7 days, but the treatment for 21 days provides a greater reduction in the MAP. In non-anesthetized SHR rats, i.v administration of GASH promoted a biphasic effect, initially characterized by hypotension (ΔMAP= -39.40 ± 11.62) and bradycardia (ΔHR= -96.06 ± 44.34) followed by hypertension (ΔMAP= 69.4 ± 15.82) and tachycardia (ΔHR = 74.4 ± 35.95). Similar results occurred with LNAME hypertensive rats and normotensive rats. When comparing the results, the decrease in MAP is greater, and the bradycardia is smaller, in the L-NAME model and SHR model compared to normotensive rats. For the evaluation of hypotension and bradycardia in vivo, we performed the previous administration of L-NAME and atropine in normotensive rats and the hypotensive effect was attenuated and the bradycardia was abolished. Subsequently, experiments in rings of superior mesenteric artery isolated from normotensive rats showed that GASH-induced relaxation (Emax= 87.5 ± 6.5%) was significantly attenuated after removal of functional endothelium (Emax= 28.4 ± 4.9%), suggesting the involvement of endothelial-derived relaxing factors. Similar results were obtained with the previous incubation with L-NAME (Emax= 23.4 ± 5.1%) and ODQ (Emax= 11.8 ± 2.7%), suggesting the involvement of the NOS/NO/GMPc pathway in the relaxation. In rings of superior mesenteric artery isolated from normotensive rat, the previous incubation with indomethacin (Emax= 97 ± 4.1%) and atropine (Emax= 81 ± 3.9%) did not modify the relaxation induced by GASH, suggesting that arachidonic acid metabolites and M3 muscarinic receptor activation are not involved in this response. In endothelial cell line from rabbit aorta, GASH increased NO production (Δ= 82 ± 7.9%), which was reduced in the presence of L-NAME (Δ= 30.2 ± 12.1%), confirming the functional results. GASH promote the phosphorylation of eNOs and Akt in primary culture of endothelial cells from pig coronary by Western blot. Previous incubation with N-acetylcysteine in rings of superior mesenteric artery isolated from normotensive rats modified the relaxation induced by GASH (Emax= 32.5 ± 6.7%), suggesting the involvement of reactive oxygen species in the relaxation. GASH was able to increase levels of superoxide production in RAEC cell culture (Δ= 57 ± 4%). Using different methodological approaches in vivo and in vitro, this study suggests that GASH induces a antihypertensive effect in vivo in different models of hypertension, as well as an endothelium-dependent relaxing effect, probably secondary to an increase in the concentration of NO through the activation of the PI3k/Akt via, and suggest that these effects may be associated with the content of phenolic compounds found in GASH. / O objetivo do presente estudo foi avaliar os efeitos cardiovasculares do vinho tinto Garziera (Cepa Shiraz, safra 2005) (GASH) do Vale do São Francisco (PE Brasil), utilizando metodologias in vitro e in vivo. Níveis de polifenóis no GASH foram medidos e GASH apresentou altos níveis de fenólicos totais e altos níveis de quercetina e de cis e trans-resveratrol. Os testes de toxicidade aguda mostraram que GASH apresentou efeito tóxico apenas em doses dez vezes maiores do que as doses utilizadas nos experimentos. O tratamento via oral com GASH por 7 dias na dose de 100 mg/kg/dia em animais normotensos não promoveu diferença na PAM e FC do grupo tratado com GASH (mmHg= 119,0 ± 2,02) em comparação ao grupo controle (mmHg = 120,20 ± 2,04). Em ratos hipertensos SHR não anestesiados tratados com GASH por 21 dias na dose de 100 mg/kg/dia, GASH diminuiu a PAM do grupo tratado (mmHg= 122,7 ± 1,52) em comparação ao grupo controle (mmHg= 156,0 ± 5,39), não ocorrendo modificação da FC. Resultados semelhantes ocorreram com ratos SHR e ratos hipertensos L-NAME tratados com GASH na dose de 100 mg/kg/dia durante 7 dias, mas o tratamento durante 21 dias proporcionou maior queda na PAM. A administração i.v. de GASH na dose de 75 mg/kg em ratos SHR desencadeou um efeito bifásico, caracterizado inicialmente por hipotensão (ΔPAM= -39,40 ± 11,62) e bradicardia (ΔFC= -96,06 ± 44,34) seguido de hipertensão (ΔPAM= 69,4 ± 15,82) e taquicardia (ΔFC= 74,4 ± 35,95). Resultados semelhantes ocorreram com ratos hipertensos LNAME e ratos normotensos. Quando se compara os resultados, a queda da PAM é maior, e a bradicardia é menor, no modelo L-NAME e SHR em relação ao rato normotenso. Para avaliação da hipotensão e bradicardia in vivo, realizamos a administração prévia de L-NAME e atropina em ratos normotensos, e a resposta hipotensora foi atenuada e a bradicardia foi abolida. Seguidamente, experimentos em anéis de artéria mesentérica superior isolada de rato normotenso mostraram que GASH induziu relaxamento (Emáx= 87,5 ± 6,5%) que foi significantemente atenuado após a remoção do endotélio funcional (Emáx= 28,4 ± 4,9%), sugerindo a participação de fatores relaxantes endoteliais. Resultados similares foram obtidos com a incubação prévia de L-NAME (Emáx= 23,4 ± 5,1%) e ODQ (Emáx= 11,8 ± 2,7%), sugerindo o envolvimento da via NOS/NO/GMPc no relaxamento. Em anéis de artéria mesentérica superior isolada de rato normotenso, a incubação prévia com indometacina (Emáx= 97 ± 4,1%), e atropina (Emáx= 81 ± 3,9%), não modificou o relaxamento induzido pelo GASH, sugerindo que os metabólitos do ácido araquidônico e a ativação do receptor muscarínico M3 não estão envolvidos nesta resposta. Em linhagem de células endoteliais da aorta de coelho, GASH aumentou a produção de NO (Δ= 82 ± 7,9%), que foi diminuída na presença de L-NAME (Δ= 30,2 ± 12,1%), corroborando os resultados funcionais. GASH promoveu a fosforilação da eNOS e da Akt em cultura primária de células endoteliais de coronária de porco por metodologia de Western blot. A incubação prévia com N-acetilcisteína em anéis de artéria mesentérica superior isolada de ratos normotensos modificou o relaxamento induzido pelo GASH (Emáx= 32,5 ± 6,7%) sugerindo o envolvimento de ROS neste relaxamento. GASH foi capaz de aumentar os níveis de produção de superóxido em cultura de células RAEC (Δ= 57 ± 4%). Este estudo, que fez uso de diferentes abordagens metodológicas in vivo e in vitro, sugere GASH induz um efeito anti-hipertensivo in vivo em modelos diferenciados de hipertensão e apresenta efeito relaxante dependente de endotélio, provavelmente secundário a um aumento na concentração de NO através da ativação da via PI3k/Akt, e que estes efeitos podem estar associados com o conteúdo de compostos fenólicos encontrados no GASH.

Intra-dialytic haemodynamic instability is a common and disabling problem which may lead to morbidity and mortality though repeated organ ischaemia, but it has proven difficult to link any particular blood pressure threshold with hard patient outcomes. The relationship between blood pressure and downstream organ ischaemia during haemodialysis has not been well characterised. Previous attempts to predict and prevent intra-dialytic hypotension have had mixed results, partly due to patient and event heterogeneity. Using the brain as the indicator organ, we aimed to model the dynamic relationship between blood pressure, real-time symptoms, downstream organ ischaemia during haemodialysis, in order to identify the most physiologically grounded, prognostic definition of intra-dialytic decompensation. Following on from this, we aimed to predict the onset of intra-dialytic decompensation using personalised, probabilistic models of multivariate, continuous physiological data, ultimately working towards an early warning system for intra-dialytic adverse events. This was a prospective study of 60 prevalent haemodialysis patients who underwent extensive, continuous physiological monitoring of haemodynamic, cardiorespiratory, tissue oxygenation and dialysis machine parameters for 3-4 weeks. In addition, longitudinal cognitive function testing was performed at baseline and at 12 months. Despite their use in clinical practice, we found that blood pressure thresholds alone have a poor trade off between sensitivity and specificity for predicting downstream tissue ischaemia during haemodialysis. However, the performance of blood pressure thresholds could be improved by stratification for the presence or absence of cerebral autoregulation, and personalising thresholds according to the individual lower limit of autoregulation. For patients without autoregulation, the optimal blood pressure target was a mean arterial pressure (MAP) of 70mmHg. A key finding was that cumulative intra-dialytic exposure to cerebral ischaemia, but not to hypotension per se, corresponded to change in executive cognitive function over 12 months. Therefore we chose cerebral ischaemia as the definition of intra-dialytic decompensation for predictive modelling. We were able to demonstrate that the development of cerebral desaturation could be anticipated from earlier deviations of univariate physiological data from the expected trajectory for a given patient, but sensitivity was limited by the heterogeneity of events even within one individual. The most useful phys- iological data streams included peripheral saturation variance, cerebral saturation variance, heart rate and mean arterial pressure. Multivariate data fusion techniques using these variables created promising personalised models capable of giving an early warning of decompensation. Future work will involve the refinement and prospective testing of these models. In addition, we envisage a prospective study assessing the benefit of autoregulation-guided blood pressure targets on short term outcomes such as patient symptoms and wellbeing, as well as longer term outcomes such as cognitive function.

Orientador: Rui Ferreira Seabra Junior / Resumo: Os acidentes ofídicos constituem um relevante problema de saúde pública, a qual deve receber cuidados rápidos e eficientes. Em relação ao ofidismo, no Brasil, somente há poucos anos foi definida uma política abrangente que enfocasse as múltiplas questões relacionadas aos acidentes humanos provocados por animais peçonhentos. Os venenos de serpentes apresentam uma mistura de compostos inorgânicos (íons metálicos) e orgânicos, sendo ricos em moléculas biologicamente ativas. Dentre essas moléculas, peptídeos, proteínas e compostos de baixa massa molecular são frequentemente estudados por apresentarem grande potencial terapêutico. Essas moléculas, se bem conhecidas, podem ser utilizadas na investigação de mecanismo moleculares e celulares. Além disso, estabelecem interessantes modelos moleculares para o desenvolvimento de estratégias biotecnológicas aplicáveis na criação de ferramentas experimentais e/ou agentes terapêuticos para a pesquisa básica e aplicada. Diante disso, a elucidação dos peptídeos hipotensores presentes no veneno crotálico da subespécie Crotalus durissus terrificus é o objetivo do presente trabalho. Este estudo poderá promover a identificação de outras moléculas hipotensoras podendo conter princípios ativos mais eficientes para o tratamento de quadros clínicos de hipertensão, doença esta que acomete milhares de pessoas no mundo todo. No presente trabalho, a porção peptídica do veneno da serpente C.d.t., apresentou rendimento médio de 12,8% em relação ao veneno b... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The snakebites are an important public health problem, which must receive quick and efficient care. Regarding the ophidism, in Brazil, only a few years ago a comprehensive policy was defined that emphasized multiple issues related to human accidents caused by venomous animals. The snake venoms present a mixture of inorganic and organic compounds, being rich in biologically active molecules. Among these molecules, peptides, proteins and low molecular weight compounds are often studied by their ability therapeutic. Those molecules, when well known, may be used in the investigation of cellular and molecular mechanism. In addition, it provides interesting molecular models for the development of biotechnological strategies applicable in the creation of experimental tools and / or therapeutic agents for basic and applied research. Therefore, the elucidation of hypotensive peptides present in the venom of Crotalus durissus terrificus subspecies is the aim of this study, once this study may promote the identification of other hypotensive molecules may contain more effective active ingredients for the treatment of clinical conditions hypertension, this disease affecting millions of people in the world. In this study, the peptide portion of the venom of the snake Cdt, performed with an average yield of 12.8% compared to the venom under total protein precipitation conditions in the presence of trifluoro acetic acid to 0.1% (v / v) and, when subjected to purification strategy for reverse... (Complete abstract click electronic access below) / Doutor

Submitted by Patrícia da Rocha Mendes (prmbio@gmail.com) on 2018-08-15T16:34:30Z No. of bitstreams: 1 TESE FINAL 2.pdf: 1912543 bytes, checksum: 5c638621228b797d59f7811694025a8c (MD5) / Approved for entry into archive by Sulamita Selma C Colnago null (sulamita@btu.unesp.br) on 2018-08-15T19:06:08Z (GMT) No. of bitstreams: 1 mendes_pr_dr_bot.pdf: 1912543 bytes, checksum: 5c638621228b797d59f7811694025a8c (MD5) / Made available in DSpace on 2018-08-15T19:06:08Z (GMT). No. of bitstreams: 1 mendes_pr_dr_bot.pdf: 1912543 bytes, checksum: 5c638621228b797d59f7811694025a8c (MD5) Previous issue date: 2016-02-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os acidentes ofídicos constituem um relevante problema de saúde pública, a qual deve receber cuidados rápidos e eficientes. Em relação ao ofidismo, no Brasil, somente há poucos anos foi definida uma política abrangente que enfocasse as múltiplas questões relacionadas aos acidentes humanos provocados por animais peçonhentos. Os venenos de serpentes apresentam uma mistura de compostos inorgânicos (íons metálicos) e orgânicos, sendo ricos em moléculas biologicamente ativas. Dentre essas moléculas, peptídeos, proteínas e compostos de baixa massa molecular são frequentemente estudados por apresentarem grande potencial terapêutico. Essas moléculas, se bem conhecidas, podem ser utilizadas na investigação de mecanismo moleculares e celulares. Além disso, estabelecem interessantes modelos moleculares para o desenvolvimento de estratégias biotecnológicas aplicáveis na criação de ferramentas experimentais e/ou agentes terapêuticos para a pesquisa básica e aplicada. Diante disso, a elucidação dos peptídeos hipotensores presentes no veneno crotálico da subespécie Crotalus durissus terrificus é o objetivo do presente trabalho. Este estudo poderá promover a identificação de outras moléculas hipotensoras podendo conter princípios ativos mais eficientes para o tratamento de quadros clínicos de hipertensão, doença esta que acomete milhares de pessoas no mundo todo. No presente trabalho, a porção peptídica do veneno da serpente C.d.t., apresentou rendimento médio de 12,8% em relação ao veneno bruto, sob condições de precipitação das proteínas totais na presença de ácido trifluoracético à 0,1% (v/v) e, quando submetida à estratégia de purificação por cromatografia líquida de fase reversa, 13 frações foram separadas. Por meio de ensaios de contratilidade de tecido isolado in vitro de músculo liso (artéria mesentérica), evidenciou-se que a fração I e a fração V apresentaram efeitos hipotensor e hipertensor, respectivamente. A fração I foi identificada com a sequência QHILIYVGVHD e massa molecular 1274,67 Da. Atualmente, esta molécula hipotensora identificada no presente trabalho foi submetida à síntese peptídica para posteriormente, avaliar-se este peptídeo hipotensor na sua forma sintética, seu efeito hipotensor por meio do ensaio de contratilidade de tecido isolado in vitro de músculo liso em relação ao fármaco Captopril. / The snakebites are an important public health problem, which must receive quick and efficient care. Regarding the ophidism, in Brazil, only a few years ago a comprehensive policy was defined that emphasized multiple issues related to human accidents caused by venomous animals. The snake venoms present a mixture of inorganic and organic compounds, being rich in biologically active molecules. Among these molecules, peptides, proteins and low molecular weight compounds are often studied by their ability therapeutic. Those molecules, when well known, may be used in the investigation of cellular and molecular mechanism. In addition, it provides interesting molecular models for the development of biotechnological strategies applicable in the creation of experimental tools and / or therapeutic agents for basic and applied research. Therefore, the elucidation of hypotensive peptides present in the venom of Crotalus durissus terrificus subspecies is the aim of this study, once this study may promote the identification of other hypotensive molecules may contain more effective active ingredients for the treatment of clinical conditions hypertension, this disease affecting millions of people in the world. In this study, the peptide portion of the venom of the snake Cdt, performed with an average yield of 12.8% compared to the venom under total protein precipitation conditions in the presence of trifluoro acetic acid to 0.1% (v / v) and, when subjected to purification strategy for reversed-phase liquid chromatography, 13 fractions were separated. Using isolated tissue contractility in vitro smooth muscle (mesenteric artery), was evidenced that the fraction I and fraction V showed hypotensive and hypertensive effects, respectively. Fraction I was identified with the QHILIYVGVHD sequence and molecular mass 1274.67 Da. Currently, this hypotensive molecule identified in this study was submitted to the peptide synthesis to subsequently evaluate this hypotensive peptide in its synthetic form, its hypotensive effect through tissue contractility assay isolated in vitro smooth muscle compared to Captopril medicine.

This thesis presents four studies investigating the phenomenon of post exercise hypotension in the human condition of pre (borderline)-hypertension. Study one investigated the effects of an acute bout of 30-minutes upright cycling on post exercise haemodynamics and compared the results to a non-exercise control condition. 9 pre-hypertensive males, mean arterial pressure (MAP) = 106 ± 5 mmHg (50 ± 10 yr), not on medication, were studied for 6 hours following 30-minutes of cycle exercise at 70% maximal oxygen consumption and following 30-minutes of seated rest. Results demonstrate that moderate intensity exercise exerts a modest fall (~6 mmHg) in arterial pressure with the hypotension sustained for 6-hours post exercise. The fall in arterial pressure equates to a significantly reduced after load when compared to both pre-exercise baseline and non-exercise control data taken at the same time of day. The arterial pressure responses transcended into a sustained reduction (20%) in systemic vascular resistance and reciprocal increase in vascular conductance for up to 2-hours post-exercise. Venous atrial natriuretic peptide (ANP) demonstrated an elevation (44%) following exercise and a significant decline (33%) in the post-exercise period mirroring the haemodynamic response. This research reveals that acute exercise is capable of sustained reductions in arterial pressure and vascular resistance beyond the usual labile fluctuations and that the octapeptide ANP may exert a modulatory influence over the post-exercise response. Increases in 02 tension beyond the physiological range induces complex effects on the circulatory system with a dominant vasoconstriction following hyperoxia. The purpose of study 2 was to assess the effects of hypoxic (16% 02) and hyperoxic (50% 62) exercise on subsequent haemodynamic control when compared with normoxia. 9 pre-hypertensive males, MAP = 106 ± 5 mmHg (50 ±10 yr), not on medication, performed 30-minutes of cycle exercise at 70% normoxic maximal oxygen consumption in hypoxia (16% O 2 ), hyperoxia (50% O 2) and normoxia(21% O2 ). Hyperoxic exercise blunted post-exercise haemodynamics by significantly attenuating the reductions (from normoxic baseline) in SVR (-45%, PO.05 vs. normoxic & hypoxic exercise immediately post-exercise) that persisted throughout 120-minutes recovery in normoxia (-35% vs. normoxic & hypoxic exercise, during recovery) and elicited a mildly hypertensive effect, with regards to MAP, whereas normoxic and hypoxic exercise elicited a hypotension compared to baseline (P < 0.05). Circulating ANP was decreased in the hyperoxic trial when compared with normoxic and hypoxic exercise [24.3 (13.4) v. 31.5 (16.3) and 29.6 (13.9) pg/ml, respectively; P < 0.05, pooled for state]. Changes in MAP were related to changes in ANP concentration only following hyperoxic exercise (r = 0.50, P < 0.01). These findings indicate that acute modest hyperoxia reflexively induces measurable physiological derangement partly explained by decreased circulating concentrations of ANP. Study three determined the role of free-radical mediated oxidative stress and redox regulation of circulating NO metabolism as a primary modulator of vascular tone following exercise in pre-hypertensive humans. Utilising the same cohort and exercise protocol as in study 1 venous blood was sampled from an antecubital vein. Plasma NO metabolites nitrate (NO" 3 ) and nitrite (NO"2 ) were determined fluorometrically, whilst S-Nitrosothiol (RSNO) concentrations were assayed by the Saville reaction Indirect markers of oxidative stress were determined spectrophotometrically detecting lipid hydroperoxides (LOOH). Exercise led to a delayed increase in LOOH by 60- minutes post-exercise (0.69 ± 0.13 v. 0.86 ± 0.18 umol/1, respectively, P < 0.05), that remained elevated until termination of the trial 6-hours post-exercise. NO'a significantly fell below baseline by 120-minutes post-exercise (10.8 ± 3.3 v. 1.1 ±1.1 u.mol/1, respectively, P < 0.05), remaining attenuated for the remainder of the study.NO'i and RSNO were unmodified in the post-exercise period. In parallel to this finding the data also indicates a significant blunting in the hyperaemic response [SVR decreased from a 31% reduction immediately (within 1-minute) post-exercise to -13 and 8% at 60- and 120-minutes post-exercise, respectively, P < 0.05] and reversal of the hypotension (P < 0.05) over the same time frame as the augmented lipid peroxidation and attenuated circulating NO~3. These results indicate that augmented oxidative stress exerts a deleterious effect on post-exercise haemodynamics and implicates a potential redox regulation pathway of NO as being a mechanism by which free radical-induced oxidative stress blunts the degree of PEH in the recovery period. The final study investigated the potential role of a redox-mediated regulation of circulating NO bioavailability as a modulator of the augmented vasoconstriction following hyperoxic exercise. The same cohort and exercise protocol were employed as in study 2 and venous blood was assayed for NO"3 , NO'a, RSNO, LOOK, & lipid /water-soluble antioxidant concentrations. Similar adverse haemodynamic effects were noted following hyperoxic exercise as reported previously in study 2. RSNO showed a significant increase following hypoxic exercise only (P < Q.Q5, state x time, interaction), whereas NO~3, NO~2 and LOOH failed to differ between conditions (P > 0.05, main effect for state [02] and state x time, interaction effects). Ascorbic acid was mobilised in response to hyperoxic exercise when compared to normoxia (P < 0.05, main effect for state [O2] and state x time, interaction effects) being significantly elevated by 120-minutes post-exercise in hyperoxia compared to normoxia and hypoxia [75.1 (31) v. 39.5 (18.3) v. 46.7 (14.2) |amol/l, respectively, P < 0.05]. This data demonstrates an effective endogenous antioxidant response and argues against a redox regulation pathway of NO metabolism as a primary mediator of blunted vasodilatation in this scenario. This elucidates a more complex regulation of arterial tone, resulting from a metabolic pathway independent of NO in older subjects with pre-hypertension. This work demonstrates that (1) aerobic exercise exerts a hypotensive effect in humans with pre-hypertension, (2) ANP plays a part in the vasodilatation following exercise, (3) Free-radical mediated oxidative stress & subsequent modulation of NO metabolism exerts a deleterious influence on post-exercise haemodynamics (4) Acute hyperoxic exercise induces a sustained vasoconstriction that is mediated via circulating ANP concentration but not by redox regulation of NO metabolism.

Isoflurano reduz o débito cardíaco e produz vasodilatação periférica resultando em hipotensão sistêmica. Hipotensão pode contribuir para morbidade e mortalidade em equinos. Queda na pressão sanguínea pode ser tratada com inotrópicos e/ou vasopressores. Levosimendana é um inotrópico sensibilizador de cálcio que produz aumento na contratilidade e diminuição na resistência vascular periférica. Dexmedetomidina é um agonista de receptor adrenérgico α2 que aumenta a resistência vascular periférica. Este estudo objetivou avaliar os efeitos cardiopulmonares da dobutamina versus levosimendana após infusão de dexmedetomidina em pôneis com hipotensão induzida pelo isoflurano. Dez pôneis saudáveis (média 13,9 ± DP 2,4 anos) foram anestesiados com detomidina, seguido por quetamina e midazolam e mantidos em um estado hipotensivo induzido por um nível profundo de anestesia com isoflurano (2 CAM). Os animais foram randomizados para receber dexmedetomidina e dobutamina (DD; n=5) ou dexmedetomidina e levosimendana (DL; n=5). Após 45 minutos do estado estável de hipotensão, as variáveis basais foram registradas. Dexmedetomidina foi administrada em 10 minutos (3,5 μg.Kg-1) e as variáveis foram registradas; em seguida, infusão contínua de dexmedetomidina iniciou (1,75 μg.Kg-1.hr-1) e as variáveis foram registradas após 45 minutos. Dobutamina (5 μg.Kg-1.min-1) ou levosimendana (12 μg.Kg-1) foram administradas e as variáveis foram registradas após 10 minutos, seguido por ITC de dobutamina ou de levosimendana (0,2 μg.Kg-1.min-1) com novo registro das variáveis após 45 minutos. Por fim, as infusões foram interrompidas e as variáveis foram registradas após 45 minutos. Isoflurano (2 CAM) reduziu as PAs, o IS e o IC, mas não afetou o IRVS. Em relação ao isoflurano, bolus de dexmedetomidina aumentou as PAs pelo aumento do IRVS e da PVC, mas não afetou o IS e o IC previamente reduzidos pelo isoflurano. Após 45 minutos, dexmedetomidina elevou a PMAP, o VD/VT, o lactato e a creatinina e reduziu as PAs, o IRVS e a FC, mas não afetou o IC. Dexmedetomidina também reduziu o CaO2, a PaO2, a Pv̅O2, a Sv̅O2, o Cv̅O2, a Hb e o ḊO2I em ambos grupos em relação ao tempo basal. Dobutamina e levosimendana aumentaram significativamente o IS e o IC, mas dobutamina aumentou as PAs, o IRVS, o IRVP, a PMAP, a PVC, o CaO2, o Cv̅O2, a Hb, o ḊO2I e reduziu a creatinina e a O2ER, enquanto levosimendana não afetou as PAs, reduziu a PVC e o IRVS e aumentou o VD/VT e o Q̇s/Q̇t. Infusão de dexmedetomidina causa prejuízos cardiopulmonares importantes a despeito de aumentar as PAs após dose em bolus IV durante hipotensão induzida pelo isoflurano em pôneis. Dobutamina é melhor alternativa que levosimendana para restaurar as funções cardiovasculares e manter oxigenação durante infusão de dexmedetomidina associada a dose alta de isoflurano em pôneis. / Isoflurane decreases cardiac output and produces peripheral vasodilation resulting in systemic hypotension. Hypotension may contribute to morbidity and mortality in equines. Drop in blood pressure can be treated with inotropic and or vasopressors. Levosimendan is a calcium sensitizer that produces increase in contractility and decrease in systemic vascular resistance. Dexmedetomidine is an α2 adrenergic-receptor agonist that increases systemic vascular resistance. This study aimed to evaluate the cardiopulmonary effects of dobutamine versus levosimendan after infusion of dexmedetomidine on isoflurane-induced hypotension in ponies. Ten healthy ponies (mean 13,9 ± SD 2,4 years) were anesthetized with detomidine followed by ketamine and midazolam and maintained at a steady hypotensive state induced by a deep level of isoflurane anesthesia (2 MAC). Animals were randomized to receive dexmedetomidine and dobutamine (DD; n=5) or dexmedetomidine and levosimendan (DL; n=5). After 45 min of steady state, baseline variables were recorded. Dexmedetomidine was administered over 10 minutes (3,5 μg.Kg-1), and variables were recorded; thereafter, dexmedetomidine CRI started (1,75 μg.Kg-1.hr-1), and variables were recorded after 45 minutes. Dobutamine (5 μg.Kg-1.min-1) or levosimendan (12 μg.Kg-1) were administered over 10 minutes and variables were recorded, followed by dobutamine or levosimendan CRI (0,2 μg.Kg-1.min-1) for 45 minutes, then variables were recorded a sixth time. Lastly, infusions were interrupted and the variables were again recorded after 45 minutes. Isoflurane (2 MAC) decreased arterial blood pressures (ABPs), SI and CI, but not affected SVR. In relation to isoflurane, bolus of dexmedetomidine increased ABPs due to augmentation on RVS and PCV, but not affected SI and CI already reduced by isoflurane. After 45 minutes, dexmedetomidine raised MPAP, VD/VT, lactate and creatinine and reduced ABPs, SVR, and HR, but not affected CI. Dexmedetomidine also reduced CaO2, PaO2, Pv̅O2, Sv̅O2, Cv̅O2, Hb and ḊO2I in both groups compared to baseline. Dobutamine and levosimendan increased SI and CI, but dobutamine increased ABPs, SVRI, PVRI, MPAP, CVP, CaO2, Cv̅O2, Hb, ḊO2I and decreased creatinine and O2ER, while levosimendan not affected ABPs, decreased CVP and SVRI and increased VD/VT and Q̇s/Q̇t. Dexmedetomidine CRI during isoflurane-induced hypotension in ponies causes statistically significant cardiopulmonary effects regardless of increasing the ABPs after bolus administration. Dobutamine is better alternative than levosimendan for restoring cardiovascular function and maintaining oxygenation during CRI dexmedetomidine associated with high-dose isoflurane in ponies. Because the proposed vasoconstriction model produced late opposite physiological effect, further studies with levosimendan in ponies and horses remain to be performed, especially in clinical patients. Likewise, further studies are justified to evaluate the effect of levosimendan on regional tissue perfusion.

Submitted by CARLOS ALBERTO RIBEIRO NETO null (carlos_ribeiro3@hotmail.com) on 2017-05-05T16:08:47Z No. of bitstreams: 1 Repositório.pdf: 829024 bytes, checksum: 091ffa9497e4fc311823094ad8b3fe64 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-05-05T16:12:53Z (GMT) No. of bitstreams: 1 ribeironeto_ca_me_arafo.pdf: 829024 bytes, checksum: 091ffa9497e4fc311823094ad8b3fe64 (MD5) / Made available in DSpace on 2017-05-05T16:12:53Z (GMT). No. of bitstreams: 1 ribeironeto_ca_me_arafo.pdf: 829024 bytes, checksum: 091ffa9497e4fc311823094ad8b3fe64 (MD5) Previous issue date: 2016-09-27 / A cirurgia ortognática sob hipotensão induzida vem sendo realizada já há um certo tempo. Os benefícios vão desde a melhora no campo cirúrgico até a menor perda sanguínea. Sendo assim, esta pesquisa nasceu de um desejo tanto da equipe de anestesia quanto dos cirurgiões envolvidos de se avaliar em números, se este procedimento sob hipotensão pode gerar algum malefício ao paciente, devido a baixa pressão em que o mesmo é mantido durante a cirurgia. Foi realizado um estudo retrospectivo no prontuário de 50 pacientes tratados com cirurgia ortognática, os quais foram anestesiados com técnica de hipotensão induzida, cujos prontuários contemplavam todas os registros de exames necessários para o estudo. Os registros desses pacientes foram então analisados em dois momentos, o pré-operatório e o pós-operatório. Com base nos resultados constatou-se que não há diferença estatisticamente significante em grande parte dos valores laboratoriais avaliados, com exceção do ETCO2. No entanto, algumas alterações encontradas em comparação com os valores tidos como normais, podem sugerir que a cirurgia ortognática sob hipotensão induzida altere a função renal. Portanto, estudos com outras metodologias e maior amostragem são necessários para confirmar esses dados. / The hypotensive anaesthesia during orthognathic surgery is routinely used in many maxillofacial services around the world. The benefits of this technique are widely described in the scientific literature, benefits such as significant decrease of blood loss, improved surgical field and reduction in operation time. The possible detriments of this technique is not well defined and few literatures addresses these issues. Therefore, this study was born in conjunction with the surgeons and anesthesiologists desire in to verify the possible hematologic changes suffered by the patients undergoing this kind of surgery and anesthesia. A prospective evaluation of some laboratory parameters in 50 patients was done, during 50 consecutive orthognathic surgeries. The results demonstrate that the majority of the evaluated parameters did not change during or after the surgery. The base excess did not change during the surgery; however, it was different from the normality average, and the renal clearance collected after two hours of surgery revealed bigger than the normal parameters; so it is possible to suggest that the orthognathic surgery under hypotension causes some negative effect in the renal function of the patients, although light. More studies with a bigger sample and different evaluations are necessary to clarify these possible effects.

Made available in DSpace on 2015-05-14T12:59:58Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4258055 bytes, checksum: ee74f99507084e08e3e09b960fa1630d (MD5) Previous issue date: 2014-03-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Previous studies have show that the organic nitrate tetrahydrofurfuryl (NTHF) induces vasorelaxation in mesenteric artery rings with involvement of the NO-sGC-PKG pathway. This study evaluated the action of NTHF on cardiovascular parameters in spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats, investigating: the nitric oxide (NO) release, acute toxicity, the NTHF effect on blood pressure and heart rate, its vasorelaxant effect and its ability to induce tolerance. NTHF increased NO levels in rat aortic smooth muscle cells (SMC) and cardiomyocites. In acute toxicity studies, a high single dose from NTHF showed low toxicity. In normotensive animals, NTHF induced hypotension after oral administration of NTHF, and bradycardic and hypotensive effects following administration of this nitrate. These results were similar that found using nitroglycerine (NTG). In addition, these effects were not altered by pretreatment with hexamethonium, a ganglionic blocker. However the treatment with methylene blue, a sGC inhibitor, promoted attenuation of both hypotensive and bradycardic effects, suggesting the involvement of the sGC pathway in these effects. In mesenteric artery rings from SHR and WKY rats precontracted with phenylephrine, NTHF induced concentration dependent vasodilatation in both intact and removed endothelium. This result suggests that the vasorelaxant effect is an endothelium derived relaxation factors (EDRFs) independent mechanism. Furthermore, in the presence of NO° scavenging (PTIO) or ODQ, a sGC inhibitor, the vasorelaxation induced by NTHF was decreased, indicating the involvement of NO-sGC pathway in this response in both SHR and WKY. In the presence of cyanamide, an aldehyde dehydrogenase (mtALDH) inhibitor, the vasorelaxant effect was diminished, suggesting that NTHF is metabolized by this enzyme. After exposure to depolarizing agent KCl, the nitrate effect was significantly attenuated, a characteristic of substances which acts by K+ channels activation. This effect was confirmed after using tetraetylamonium (TEA), a K+ channels inhibitor. In normotensive rats treated with NTHF, the acute administration of NTHF promoted bradycardia and hypotension were are not changed in relation to which those observed in vehicle-treated animals, suggesting that organic nitrate did not induce in vivo tolerance. In vitro tolerance was evaluated in both mesenteric artery rings from animals pretreated with NTHF as well as rings previously exposed to isolated concentrations of NTHF. The vasorelaxant effect was not modified by pretreatment or exposure to NTHF, unlike that observed with NTG. In rings treated with NTG, the effect induced by NTHF was not modified, indicating that NTHF did not promote in vitro tolerance. The results demonstrated that NTHF promoted hypotensive and bradycardic effects in both SHR and WKY rats, with involvement of sGC enzyme; NTHF induced a vasorelaxant effect with participation of NO-sGC-PKG pathway and K+ channels. These effects seem to be mediated by NO release from cardiomyocites and SMC. Finally this study will help to advance the field towards clinical trials, since NTHF caused low toxicity and this nitrate was devoid of in vivo and in vitro tolerance. / Estudos anteriores demonstraram que o nitrato orgânico tetra-hidrofurfurílico (NTHF), promoveu efeito vasorrelaxante em artéria mesentérica de ratos normotensos, com envolvimento da via NO-sGC-PKG. O objetivo deste trabalho foi avaliar os efeitos cardiovasculares induzidos pelo NTHF em ratos espontaneamente hipertensos (SHR) e normotensos Wistar Kyoto (WKY), investigando: a liberação de óxido nítrico (NO), a toxicidade aguda, o efeito do NTHF sobre pressão arterial (PA) e frequência cardíaca (FC), o efeito vasodilatador desse composto, além de sua capacidade em induzir tolerância. Em células musculares lisas vasculares (CMLV) de aorta de rato e cardiomiócitos, NTHF promoveu aumento dos níveis de NO. Na avaliação da toxicidade aguda, NTHF foi administrado por via oral numa dose elevada, e nestas condições o nitrato orgânico apresentou baixa toxicidade. Em animais normotensos, NTHF promoveu hipotensão quando administrado por via oral e efeito hipotensor e bradicárdico após a administração intravenosa, semelhante ao observado pelo gliceril trinitrato (GTN). Este efeito não foi alterado pelo prétratamento com hexametônio, um bloqueador nicotínico ganglionar. Porém, o tratamento com azul de metileno, inibidor da enzima ciclase de guanilil solúvel (sGC), promoveu diminuição da resposta, indicando a participação da sGC nos efeitos hipotensor e bradicárdico. Em animais WKY e SHR NTHF promoveu efeito hipotensor e bradicárdico. Em anéis de artéria mesentérica de ratos SHR e WKY, pré-contraídos com fenilefrina, NTHF promoveu vasodilatação concentraçãodependente, com endotélio vascular intacto ou removido, sugerindo um efeito independente da liberação dos fatores relaxantes derivados do endotélio (EDRFs). Na presença do sequestrador de NO radicalar (PTIO) ou do inibidor seletivo da sGC (ODQ), o efeito vasorrelaxante do NTHF foi atenuado, indicando a participação da via NO-sGC tanto em SHR quanto WKY. Na presença de cianamida, um inibidor da enzima aldeído desidrogenase mitocondrial (mtALDH), o efeito vasorrelaxante foi atenuado, indicando que o nitrato é metabolizado por esta enzima. Após a exposição ao agente despolarizante KCl e após adição de tetraetilamônio (TEA), inibidor de canais para K+, o efeito do NTHF foi diminuído. Em animais normotensos prétratados com NTHF, a administração aguda de NTHF hipotensão e bradicardia, comparáveis às observadas no grupo controle, sugerindo que o NTHF não induz tolerância in vivo. A tolerância in vitro foi avaliada em artéria mesentérica de animais tratados previamente com NTHF, quando previamente expostos a concentrações isoladas do nitrato. O efeito vasorrelaxante não foi modificado pelo tratamento ou exposição prévia ao NTHF. Efeito contrário ao obtido com GTN. Em anéis prétratados com GTN, o efeito induzido pelo NTHF não foi modificado, sugerindo que o nitrato em estudo não promove tolerância in vitro. Os resultados demonstram que o NTHF promoveu efeito hipotensor e bradicárdico em animais normotensos e hipertensos, com envolvimento da enzima sGC; apresentou efeito vasorrelaxante, com participação da via NO-sGC-PKG e também de canais para K+. Esses efeitos parecem ser mediados por meio da liberação de NO tanto em CMLV quanto em cardiomiócitos. Por fim, NTHF evidencia um potencial clínico por apresentar baixa toxicidade e não induzir tolerância in vivo e in vitro

Made available in DSpace on 2015-05-14T13:00:12Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1253693 bytes, checksum: 473208aa372beaf58b2dc01deecdc9be (MD5) Previous issue date: 2010-03-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Organic nitrates are nitric oxide (NO) donors used in the treatment of cardiovascular diseases mimicking the role of endogenous NO. This study evaluated organic nitrates newly synthesized from glycerin, which cardiovascular actions had not yet been investigated. Therefore, the cardiovascular effects produced by organic nitrates derived from glycerin: 2-nitrate-1,3-dimethoxypropan (NDMP), 2-nitrate-1,3-diethoxypropan (NDEP), 2-nitrate-1 ,3-dipropoxypropan (NDPP) and 2-nitrate-1,3-dibutoxypropan (NDBP) in rats were investigated using in vitro and in vivo approaches. For in vitro studies, animals were euthanized and the superior mesenteric artery was isolated. Artery rings were kept in tanks with Tyrode at 37 ° C aerated with carbogen, then were attached to a force transducer (Fort 10, WPI, Sarasota, USA) coupled to a data acquisition system data (Miobath-4, WPI, Sarasota, USA) under a tension of 0.75 g for 1 hour. After this period, preparations were pre-contracted with phenylephrine (FEN) 10 &#956;M or KCl 80 mM and then increasing concentrations of organic nitrates were cumulatively added. The nitrate with the most promising effects was selected for further studies and concentration-response curves of the compound selected in the presence of HDX, a hijacker of NO; ODQ, inhibitor of soluble guanylyl cyclase, KCl 20 mM, a modulator of potassium efflux, and blockers for calcium-sensitive potassium channel (TEA, 1 mM), blockers for ATP-sensitive potassium channel (GLIB, 1 &#61549;M) and blockers for voltage-operated potassium channel (4-AP, 1 mM) were obtained. All compounds showed vasorelaxant activity endothelium-independent in superior mesenteric artery rings, being the NDBP was the most potent agent with Emax = 105.4 ± 2.7% in rings pre-contracted with FEN and Emax = 82, 7 ± 7.9% in KCl 80 mM induced contraction. The vasorelaxation was significantly attenuated in the presence of HDX and ODQ with Emax = 62.8 ± 14.9% and Emax = 15.2 ± 9.2%, respectively. In the presence of KCl 20 mM the vasorelaxat response was also reduced [Emax = 70.6 ± 15.02%] as well as in the presence of TEA [Emax = 87.97 ± 5.78%]; GLIB [Emax = 78, 2 ± 6.5%] and 4-AP, a lesser extent [Emax = 94.65 ± 6.6%]. For in vivo studies, we investigated the changes in blood pressure (BP) and heart rate (HR) in conscious rats treated acutely with NDBP. Intravenous administration of NDBP (2, 5, 10, 15 and 20 mg/kg, randomly) produced hypotension (-6 ± 1.7, -22 ± 6.8, -58 ± 3.7, -70 ± 5.5, -77 ± 5.4 mmHg) and bradycardia (-12 ± 5, -40 ± 19.7, -133 ± 18.6, -179 ± 23.5, and -266 ± 12.4 bpm) in a dose-dependent manner. Thus, the vasorrelaxant response produced by NDBP possibly involves the NO release and subsequent activation of the CGs/GMPc/PKG pathway and BKCa, KATP and KV channels. These mechanism of action may be contributing to hypotension and bradycardia showed in non-anesthetized normotensive rats. / Os nitratos orgânicos são doadores de óxido nítrico (NO) utilizados no tratamento de doenças cardiovasculares mimetizando o papel do NO endógeno. Neste estudo foram avaliados nitratos orgânicos recém-sintetizados a partir da glicerina cujas ações cardiovasculares ainda não haviam sido investigadas. Portanto, os efeitos cardiovasculares do 2-nitrato-1,3-dimetoxipropano (NDMP), 2-nitrato-1,3-dietoxipropano (NDEP), 2-nitrato-1,3-dipropoxipropano (NDPP) e 2-nitrato-1,3-dibutoxipropano (NDBP) em ratos normotensos foram observados, utilizando técnicas in vitro e in vivo. Para os estudos in vitro, os animais foram eutanasiados e a artéria mesentérica superior foi isolada. Anéis de artéria mesentérica superior isolada de rato foram mantidos em cubas contendo Tyrode a 37 ºC gaseificado com carbogênio, em seguida foram fixados a um transdutor de força (FORT 10, WPI, Sarasota, EUA), acoplado a um sistema de aquisição de dados (Miobath-4, WPI, Sarasota, EUA) sob tensão de 0,75 g, durante 1 hora. Após este período, as preparações foram pré-contraídas com fenilefrina (FEN) 10 &#956;M ou KCl 80 mM e, em seguida, concentrações crescentes dos nitratos orgânicos, foram adicionadas cumulativamente. O nitrato com efeito mais promissor foi selecionado para estudos subsequentes e foram obtidas curvas concentração-resposta do composto na presença de HDX, sequestrador de NO; ODQ, inibidor da ciclase de guanilil solúvel; KCl 20 mM, modulador do efluxo de potássio; e bloqueadores de canais para K+ sensíveis ao cálcio (TEA, 1 mM), ao ATP (GLIB, 1 &#61549;M) e operados por voltagem (4-AP, 1 mM). Todos os compostos apresentaram atividade vasorrelaxante em anéis de artéria mesentérica superior isolada de rato independente do endotélio funcional, sendo o NDBP o mais potente com Emáx = 105,4 ± 2,7 % em anéis pré-contraídos com FEN e Emáx = 82,7 ± 7,9 % na contração induzida por KCL 80 mM. O vasorrelaxamento foi significativamente atenuado na presença de HDX e ODQ, com Emáx = 62,8 ± 14,9 % e Emáx = 15,2 ± 9,2 %, respectivamente. Na presença de KCl 20 mM a resposta vasorrelaxante também foi reduzida [Emáx = 70,6 ± 15,02 %], bem como na presença do TEA [Emáx = 87,97 ± 5,78 %]; GLIB [Emáx = 78,2 ± 6,5 %] e 4-AP, em menor proporção [Emáx = 94,65 ± 6,6 %]. Para os estudos in vivo, foram investigadas as alterações na pressão arterial (PA) e frequência cardíaca (FC) em ratos não-anestesiados tratados agudamente com o NDBP. A administração aleatória do NDBP (2, 5, 10, 15 e 20 mg/kg, i. v) produziu hipotensão (-6 ± 1,7; -22 ±6,8; -58 ± 3,7; -70 ± 5,5; -77 ± 5,4 mmHg) e bradicardia (-12 ± 5; -40 ± 19,7; -133 ± 18,6; -179 ± 23,5; e -266 ± 12,4 bpm) de maneira dose-dependente. Deste modo, a resposta vasorrelaxante promovida pelo NDBP possivelmente envolve a liberação de NO e posterior ativação da via CGs/GMPc/PKG e canais para K+ do tipo BKCa; KATP e KV. Este mecanismo de ação pode estar contribuindo para a hipotensão e bradicardia observadas em animais normotensos não-anestesiados.