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1.
Kinesiologia ; 41(4): 327-340, 20221215.
Article in Spanish, English | LILACS-Express | LILACS | ID: biblio-1552421

ABSTRACT

Introducción. La hipertensión arterial pulmonar (HAP) es una enfermedad que presenta un elevado índice de mortalidad en la población pediátrica. Para su diagnóstico, el gold standard es la prueba de reactividad vascular pulmonar (PRVP), debido a que permite medir la respuesta vasodilatadora del lecho vascular pulmonar frente a la administración de moléculas con acción terapéutica, como el óxido nítrico inhalado (iNO). Esta prueba al ser positiva se asocia a un mejor pronóstico. En la actualidad existe incertidumbre y falta de consenso sobre la indicación y administración de iNO durante la PRVP. Objetivo. Describir el uso reportado en la literatura sobre iNO en PRVP en sujetos pediátricos con HAP. Métodos. Revisión sistemática exploratoria sensible en bases de datos PubMed, Epistemonikos, Cochrane, Scopus, Lilacs y Scielo, que describen el uso de iNO durante la PRVP en sujetos pediátricos con HAP. Resultados. se identificaron 8.906 artículos, de los cuales se seleccionaron 5 para la revisión cualitativa. La PRVP se realizó durante el cateterismo cardiaco derecho (CCD) en sujetosentre 2 semanas y 18 años de edad. Los diagnósticos fueron HAP primaria, idiopática y asociada a patología cardiaca congénita, cardiomiopatía y enfermedad pulmonar. Esta prueba fue realizada en sujetos sólo con soporte de oxígeno o con sedación profunda en ventilación mecánica invasiva, con dosis variables de oxígeno (21 y 100%) e iNO (3 y 80 ppm), o asociado a otras moléculas como iloprostol®, dilitiazem, sildenafil y/o epoprostenol. La administración de iNO disminuyó presión de arteria pulmonar y la resistencia vascular pulmonar, con mantención de presión arterial sistémica y gasto cardiaco y sin complicaciones asociadas a su uso. Conclusiones. Existen escasos estudios sobre iNO en PRVP pediátrica y con calidad metodológica limitada. El iNO se utiliza como método diagnóstico de vaso reactividad en sujetos pediátricos con HAP asociada a cardiopatía congénita, primaria o secundaria. Los protocolos para su uso son variables con dosis entre 20 y 40 ppm, con o sin uso de oxigeno adicional, con tiempos poco precisos y sin consenso en equipos de administración.


Background. Pulmonary arterial hypertension (PAH) is a disease that has a high mortality rate among the pediatric population. For its diagnosis, the pulmonary vascular reactivity test (PVRT) is considered the "Gold Standard", because it allows to measure the vasodilator response of pulmonary vascular circulation with the administration of molecules with therapeutic action, such as inhaled nitric oxide (iNO). This test, when positive, is associated with a better prognosis of the disease. Currently, there's uncertainty and lack of consensus on the indication and administration of iNO during the PVRT. Objetives. to describe use of iNO in PVRT in pediatric users with PAH reported in the literature. Methods. Scoping review of studies published between 1992 and 2021 in PubMed, Epistemonikos, Cochrane, Scopus, Lilacs and Scielo databases, which describe the use of iNO during PVRT in pediatric users with PAH, in English and Spanish. Primary and secondary studies with a sensitive search strategy were considered. Results. 8,906 articles were identified, 40 were selected by title, 8 by full text, and 5 for final qualitative review. Of the total of articles selected, 3 were primary and 2 secondary studies. PVRT was performed during right heart catheterization (RHC) in a population between 2 weeks and 18 years old. Diagnoses were primary PAH, idiopathic PAH and PAH associated with congenital heart disease, cardiomyopathy and pulmonary disease. This test was carried out in subjects on spontaneous ventilation with oxygen support or with deep sedation in invasive mechanical ventilation, with variable oxygen doses between 21 and 100%, with exclusive use of iNO between 3 and 80 ppm, being more used between 20 and 40 ppm, or associated with other molecules such as iloprostol®, dilithiazim, sildenafil and / or epoprostenol. In all selected studies, administration of iNO decreased PAP (pulmonary artery pressure) and PVR (pulmonary vascular resistance), with maintenance of SBP (systemic arterial blood pressure) and cardiac output. The primary studies were made up of pre and post-test of serial or parallel interventions. The selected studies of iNO in PVRT did not report complications associated with its use. Conclusions. studies on iNO in pediatric PVRT are scarce in number of publications and methodological quality. iNO is used as a diagnostic method of vasoreactivity in pediatric users with PAH associated with congenital, primary, or secondary heart disease. The protocols for its use are variable with recommended doses between 20 and 40 ppm, with or without the use of additional O2, with imprecise times and without consensus in administration equipment. The response to PVRT serves as a guide for the treatment and prognosis of pediatric users with PAH.

2.
Motriz (Online) ; 28: e10220005522, 2022. tab, graf
Article in English | LILACS-Express | LILACS | ID: biblio-1406006

ABSTRACT

Abstract Aim: We investigated the effects of continuous or interval aerobic exercise training on vascular reactivity of female rats fed with fructose. Methods: Female Wistar rats (8-wk old) were divided into: sedentary (SD), continuous training (CTR), and interval training (ITR). Moderate intensity training protocols consisted of running 3 days/week for 7 weeks. CTR ran 40 min at 30%-40% of the maximal speed (MS) and TRI consisted of 7 sets of 1 min at 70% of MS followed by 3 min at 35% of MS. Animals were fed with standard chow and fructose (10%) in drinking water. Concentration-response curves to acetylcholine and phenylephrine, and oxidative stress biomarkers, were determined in the aorta. Body weight gain, visceral fat, and plasma triglycerides and glucose were also evaluated. Results: Endothelium-dependent relaxation was significantly increased by both exercise regimens (CTR: Emax = 85 ± 6% and ITR: Emax = 84 ± 1%) compared to sedentary rats (SD: Emax = 62 ± 5%). The contractile maximal response was not different but phenylephrine potency was increased in CTR (pEC50: 8.41 ± 0.19) and reduced in ITR (pEC50: 7.06 ± 0.11) compared to SD (pEC50: 7.77 ± 0.08). In addition, the generation of superoxide was lower in trained groups as compared with sedentary (about −28% in CTR and −22% in ITR). TBARS and nitrate/nitrite levels were not modified. Compared to the SD group, ITR gained 39% less body weight and CTR has 29% less visceral fat. Glucose and triglycerides were not modified. Conclusion: CTR and ITR, carried out 3 days/week, were efficient to improve endothelium-dependent relaxation and reduce superoxide generation in the aorta from female rats fed with fructose.

3.
Braz. j. biol ; 77(4): 781-786, Nov. 2017. tab, graf
Article in English | LILACS | ID: biblio-888808

ABSTRACT

Abstract Previous studies performed in marine fish (I. conceptionis and G. laevifrons) showed that indomethacin blocked arterial contraction mediated by acetylcholine (ACh). The objective of this study was to determine if contraction induced by acetylcholine is mediated by the cyclooxygenase pathway in several arterial vessels in the Chilean frog Calyptocephalella gayi. Arteries from the pulmonary (PA), dorsal (DA), mesenteric (MA) and iliac (IA) regions were dissected from 6 adult specimens, and isometric tension studies were done using dose response curves (DRC) for ACh (10-13 to 10-3 M) in presence of a muscarinic antagonist (Atropine 10-5 M) and an unspecific inhibitor of cyclooxygenases (Indomethacin, 10-5M). All the studied arteries exhibited vasoconstriction mediated by ACh. This vasoconstriction was abolished in the presence of atropine in DA, MA and IA and attenuated in PA. Indomethacin abolished the vasoconstriction in MA and attenuated the response in PA, DA and IA. Similar to marine fish, C. gayi have an ACh-mediated vasoconstrictor pattern regulated by muscarinic receptors that activate a cyclooxygenase contraction pathway. These results suggest that the maintenance in vasoconstrictor mechanisms mediated by ACh→COX →vasoconstriction is conserved from fish to frogs.


Resumo Estudos feitos em peixes marinhos (I. conceptionis e G. laevifrons) têm demostrado que a indometacina bloqueia a contração arterial mediada por acetilcolina (ACh). O objetivo do presente estudo foi avaliar o efeito da via da ciclooxigenase na contração induzida por ACh em vasos arteriais da rã chilena Calyptocephalella gayi. Foram dissecadas regiões das artérias pulmonares (PA), dorsal (DA), mesentérica (MA) e ilíaca (IA) de seis espécimes adultos e realizados estudos de tensão isométrica utilizando curvas dose-resposta (CDR) de ACh (10-13 a 10-3 M) na presença de um antagonista muscarínico (atropina, 10-5 M) e um inibidor das ciclooxigenases (indometacina, 10-5 M). Todas as artérias evidenciaram uma resposta vasoconstritora mediada por ACh. Esta resposta vasoconstrictora foi suprimida na presença de atropina nas artérias DA, MA, IA e atenuada na PA. A indometacina suprimiu a vasoconstrição na artéria MA e atenuou a resposta nas artérias PA, DA e IA. Tal como os peixes marinhos, a C. gayi tem um padrão de vasoconstrição mediado por Ach que é regulado pelos receptores muscarínicos e pela ciclooxigenase. Estes resultados sugerem a conservação dos mecanismos vasoconstrictores mediados por ACh→COX em peixes e rãs.


Subject(s)
Animals , Anura/physiology , Atropine/pharmacology , Vasoconstriction/drug effects , Indomethacin/pharmacology , Cyclooxygenase Inhibitors/pharmacology , Muscarinic Antagonists/pharmacology , Arteries/drug effects , Acetylcholine/pharmacology , Chile , Prostaglandin-Endoperoxide Synthases/metabolism
4.
Braz. j. biol ; 76(2): 500-505, Apr.-June 2016. tab, graf
Article in English | LILACS | ID: lil-781412

ABSTRACT

Abstract Previous studies performed in intertidal fish (Girella laevifrons),as well as marine fish (Isacia conceptionis), showed that acetylcholine (ACh) produced contractions mediated by cyclooxygenases that were dependent on the area and potency of contraction in several arterial vessels. Given that the role of nitric oxide is poorly understood in fish, the objective of our study was to evaluate the role of nitric oxide in branchial afferent (ABA), branchial efferent (ABE), dorsal (DA) and mesenteric (MA) arterial vessels from both Girella laevifrons and Isacia conceptionis. We studied afferent and efferent branchial, dorsal and mesenteric arteries that were dissected from 6 juvenile specimens. Isometric tension studies were done using dose response curves (DRC) for Ach (10–13 to 10–3 M) and blockade with L-NAME (10–5 M), and DRC for sodium nitroprusside (SNP, a donor of NO). L-NAME produced an attenuation of the contractile response in the dorsal, afferent and efferent branchial arteries and a potentiation of the contraction in the MA. SNP caused 70% dilation in the mesenteric artery and 40% in the dorsal artery. Our results suggest that Ach promotes precarious dilatation in MA mediated by NO; data that is supported by the use of sodium nitroprusside. In contrast, in the vessels DA, ABA and EBA our results support that the pathway Ach-NO-relaxation is absent in both species.


Resumo Estudos anteriores, realizados no peixe intertidal (Girellalaevifrons) no peixe marinho (Isacia conceptionis), mostram que a acetilcolina (Ach) provoca contrações mediadas por ciclooxigenases que eram dependentes da área e potencia da contração em vários vasos arteriais. Tendo em conta que o papel do óxido nítrico é mal compreendido em peixes, o objetivo do nosso estudo foi avaliar o papel do óxido nítrico em vasos arteriais de ambos os peixes Girella laevifrons e Isacia conceptionis. Nós estudamos os vasos aferente, branquial (ABA), eferente branquial (ABE), dorsal (DA) e mesentérica (MA), que foram dissecadas de seis espécimes juvenis. Estudos de tensão isométrica foram realizados utilizando as curvas de dose-resposta (DRC) para Ach (10–13 a 10–3M) e bloqueio com L-NAME (10–5 M), e na DRC para o nitroprussiato de sódio (SNP, doador do NO). L- NAME produziu uma atenuação da resposta contrátil nas artérias dorsais, aferentes e eferentes branquial e uma potenciação da contração no MA. SNP causaram 70% da dilatação da artéria mesentérica e 40% na artéria dorsal. Nossos resultados sugerem que Ach promove dilatação precária em MA mediada por NO; dados que é suportada pela utlilização de nitroprussiato de sódio. Em contraste, nos vasos de DA, ABA e EBA nossos resultados suportam que a via de Ach-NO-relaxamento está ausente em ambas as espécies.


Subject(s)
Animals , Arteries/physiology , Vasodilation/physiology , Fishes/anatomy & histology , Fishes/physiology , Nitric Oxide/metabolism , Perciformes/anatomy & histology , Perciformes/physiology , Nitroprusside/metabolism , Acetylcholine/metabolism , Nitric Oxide Donors/metabolism
5.
Araçatuba; s.n; 2016. 107 p. ilus, graf, tab.
Thesis in Portuguese | LILACS, BBO | ID: biblio-881587

ABSTRACT

O TERPY promove efeito hipotensor de maior magnitude em ratos hipertensos (SHR e 2R-1C) do que em ratos normotensos (Wistar e 2R). Foi demonstrado anteriormente que o endotélio prejudica o efeito vasodilatador do TERPY em aorta de Wistar. No entanto, observamos que o endotélio melhora os efeitos vasodilatadores do TERPY em aorta de SHR. Vasos sanguíneos de menor calibre, tais como as artérias de resistência, estão associadas ao controle da resitência vascular periférica e da pressão arterial. Nossa hipótese é que o TERPY induz relaxamento nas artérias mesentéricas de resistência em SHR e que as células endoteliais modulam positivamente o efeito do TERPY nestes vasos sanguíneos. Portanto, o nosso objetivo foi avaliar o efeito vasodilatador do TERPY em anéis com e sem endotélio de artéria mesentérica de ratos SHR, o seu mecanismo de relaxamento e a participação da NOS sobre esse efeito. e a Nossos resultados mostraram que o TERPY induziu um efeito vasodilatador dependente da concentração em anéis de artérias mesentéricas (2º e 3º ramos) de SHR e de ratos Wistar. A potência do TERPY foi maior em anéis intactos do que em anéis sem endotélio em artérias mesentéricas de SHR, mas em Wistar o endotélio prejudicou o efeito do TERPY. Nas artérias mesentéricas sem endotélio de SHR, o efeito do TERPY é dependente da atividade da guanilato ciclase solúvel e de canais para potássio. Nas artérias mesentéricas intactas de SHR, o efeito de TERPY depende da atividade de eNOS, mas não é dependente das atividades de nNOS, iNOS ou da via da ciclooxigenase. O TERPY promove a fosforilação da eNOS nos resíduos de serina1177 e aumenta a concentração de óxido nítrico em células endoteliais isoladas de artérias mesentéricas de SHR. Nossos resultados mostraram que a guanilato ciclase solúvel, os canais para potássio e a eNOS estão envolvidos no efeito vasodilatador estimulado pelo TERPY nas artérias de resistência mesentérica de SHR. Numa segunda parte deste estudo, avaliamos o mecanismo de ação de TERPY e seu efeito sobre a atividade da eNOS em células endoteliais. As células HUVEC, WT-HEK e HEK-eNOS foram tratadas com TERPY em diferentes tempos (0 a 60 minutos). Foram analisados por Western blotting o efeito do TERPY sobre a fosforilação de eNOS, monômero e dímero da eNOS e sobre monômero e oligômero de caveolina-1. Também foi avaliado o efeito do TERPY na interação eNOS/Cav-1 através de co-imunoprecipitação. As alterações induzidas pelo TERPY sobre as concentrações de espécies reativas de oxigênio e peroxinitrito em células endoteliais foram medidas usando sonda DHE e biossensor 7-CBA, respectivamente. A concentração de óxido nítrico (NO) foi avaliada por sonda DAF-FM e sensor Cooper. O TERPY promoveu desacoplamento e disfunção da eNOS, dependente de BH4. A desestabilização dos oligômeros da caveolina-1 foi induzida pelo TERPY. Consequentemente, o TERPY reduziu a interação eNOS/Cav-1 e promoveu ativação da eNOS. Nossos resultados mostraram que a atividade da eNOS pode ser regulada de duas maneiras diferentes pelo TERPY. O TERPY promove desacoplamento e fosforilação da eNOS, promovendo uma estratégia diferente para a regulação da atividade desta enzima. As moléculas químicas ou biológicas como o TERPY que regulam a atividade da eNOS e aumentam a produção e a biodisponibilidade de NO teriam ações terapêuticas importantes para o tratamento de doenças vasculares associadas a hipertensão(AU)


TERPY promotes a hypotensive effect with greater magnitude in hypertensive rats (SHR and 2K-1C) than in normotensive rats (Wistar and 2K). Previously, it was demonstrated that endothelium impairs vasodilatory effect of TERPY in Wistar aorta. However, we observed that endothelium improves the vasodilatory effect of TERPY in SHR aorta. Smaller blood vessels, such as mesenteric arteries, are associated with the control of peripheral vascular resistance and blood pressure. We hypothesized that TERPY induces relaxation on mesenteric resistance arteries in SHR and endothelial cells modulate positively the TERPY's effect on these blood vessels. Therefore, our goal was to evaluate the vasodilator effect of TERPY in rings with and without endothelium of mesenteric arteries in SHR, the mechanism of relaxation and the participation of NOS on this effect. Our results show TERPY induced a concentration-dependent vasodilator effect in mesenteric arteries (2nd and 3 rd branches) rings from SHR and Wistar. The potency of TERPY was higher in intact than in denuded rings from SHR, but in Wistar, endothelium impair the TERPY's effect. In denuded mesenteric arteries from SHR, the relaxation effect induced by TERPY is dependent of soluble guanylate cyclase and activation of potassium channel. However, in intact mesenteric arteries from SHR, TERPY´s effect is modulated by eNOS activity, but it is not dependent of nNOS, iNOS or cyclooxygenase pathway activities. TERPY promotes eNOS3 Ser1177 phosphorylation and increases nitric oxide concentration in isolated endothelial cells of mesenteric arteries from SHR. Together, our results showed that soluble guanylate cyclase, potassium channels, and eNOS are involved in the vasodilator effect of TERPY in mesenteric resistance arteries from SHR. In a second part of this study, we aimed to evaluate the mechanism of action of TERPY and its effect on eNOS activity in endothelial cells. HUVEC, WT-HEK and HEK-eNOS cells were treated with TERPY at different times (0 to 60 minutes). Were analyzed by western blotting the TERPY`s effect on eNOS monomer, dimer and phosphorylation and on monomer and oligomer of caveolin-1. It was also evaluated the effect of TERPY in the interaction between eNOS/Cav-1 through co-immunoprecipitation. Alterations induced by TERPY on reactive oxygen species and peroxynitrite concentrations in endothelial cells were measured by using DHE probe and biosensor 7-CBA, respectively. Nitric oxide fluorescence was assessed by DAF-FM probe and Cooper sensor. TERPY promoted eNOS uncoupling and eNOS dysfunction, which is BH4-dependent. Caveolin-1 oligomers destabilization was induced by TERPY. Consequently, TERPY reduced eNOS/Cav-1 interaction and promoted eNOS activation. Our results show that eNOS activity can be regulated in two different ways by TERPY, leading to eNOS uncoupling and leading to eNOS phosphorylation, promoting a strategy for eNOS regulation. Chemical or biological molecules as TERPY that regulates eNOS activity and increase NO production and bioavailability are potential therapeutic drugs for the treatment of vascular diseases associated with hypertension(AU)


Subject(s)
Animals , Rats , Nitric Oxide , Nitric Oxide Synthase Type III , Rats, Inbred SHR , Vasodilation , Caveolin 1 , Endothelium, Vascular , Hypertension , Mesenteric Arteries , Vascular Diseases
6.
The Korean Journal of Physiology and Pharmacology ; : 621-628, 2016.
Article in English | WPRIM | ID: wpr-728268

ABSTRACT

Hypertension can be caused by various factors while the predominant causes include increase in body fluid volume and resistance in the circulatory system that elevate the blood pressure. Consumption of probiotics has been proven to attenuate hypertension; however, the effect is much strain-dependent. In this study, a newly isolated Lactobacillus casei (Lb. casei) strain C1 was investigated for its antihypertensive properties in spontaneously hypertensive rats (SHR). Lactic acid bacteria (LAB) suspension of 11 log colony-forming unit (CFU) was given to SHR (SHR+LAB, n=8), and phosphate buffer saline (PBS) was given as a control in SHR (SHR, n=8) and in Wistar rats as sham (WIS, n=8). The treatment was given via oral gavage for 8 weeks. The results showed that the weekly systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP) and aortic reactivity function were remarkably improved after 8 weeks of bacterial administration in SHR+LAB. These effects were mostly attributed by restoration of wall tension and tensile stress following the bacterial treatment. Although not statistically significant, the level of malondialdehye (MDA) in SHR+LAB serum was found declining. Increased levels of glutathione (GSH) and nitric oxide (NO) in SHR+LAB serum suggested that the bacterium exerted vascular protection through antioxidative functions and relatively high NO level that induced vasodilation. Collectively, Lb. casei strain C1 is a promising alternative for hypertension improvement.


Subject(s)
Arterial Pressure , Bacteria , Blood Pressure , Body Fluids , Glutathione , Hypertension , Lactic Acid , Lacticaseibacillus casei , Lactobacillus , Nitric Oxide , Probiotics , Rats, Inbred SHR , Rats, Wistar , Stem Cells , Vasodilation
7.
Braz. j. biol ; 75(2): 362-367, 05/2015. tab, graf
Article in English | LILACS | ID: lil-749704

ABSTRACT

Preliminary studies showed that dorsal artery contraction mediated by acetylcholine (ACh) is blocked with indomethacin in intertidal fish (G. laevifrons). Our objective was to characterize the cholinergic pathway in several artery vessels of the I. conceptionis. Afferent and efferent branchial, dorsal and mesenteric arteries were dissected of 6 juvenile specimens, isometric tension studies were done using doses response curves (DRC) for Ach (10–13 to 10–3 M), and cholinergic pathways were obtained by blocking with atropine or indomethacin. CRC to ACh showed a pattern of high sensitivity only in efferente branchial artery and low sensibility in all vessels. Furthermore, these contractions were blocked in the presence of atropine and indomethacin in all vessels. Our results corroborate previous results observed in intertidal species that contraction induced by acetylcholine is mediated by receptors that activate a cyclooxygenase contraction pathway.


Estudos preliminares mostraram que a contração da artéria dorsal mediada por acetilcolina (ACh) é bloqueada com indometacina em peixes marinhos (G. laevifrons). Nosso objetivo foi caracterizar a via colinérgica em várias artérias de I. conceptionis. Artérias aferentes e eferentes branquiais, dorsais e mesentéricas foram dissecadas de 6 espécimes juvenis. Os estudos de tensão isométrica foram feitos utilizando-se a curva dose - resposta (CDR) para Ach (10–13 a 10–3M), e identificaram-se as vias colinérgicas, bloqueando com atropina e indometacina. CRC para ACh mostrou um padrão de alta sensibilidade na artéria eferentes branquiais e baixa sensibilidade em todos os vasos sanguineos. Essas contrações foram bloqueadas na presença de atropina e indometacina em todas as artérias avaliadas. Nossos resultados confirmam que a contração induzida por acetilcolina é mediada por receptores muscarínicos que ativam ciclo-oxigenase.


Subject(s)
Animals , Acetylcholine/pharmacology , Arteries/drug effects , Perciformes/metabolism , Prostaglandin-Endoperoxide Synthases/drug effects , Arteries/physiology , Atropine/pharmacology , Dose-Response Relationship, Drug , Indomethacin/pharmacology , Perciformes/classification , Prostaglandin-Endoperoxide Synthases/metabolism , Signal Transduction
8.
Rev. cuba. med ; 53(4): 417-429, sep.-dic. 2014.
Article in Spanish | LILACS, CUMED | ID: lil-735340

ABSTRACT

INTRODUCCIÓN: la aterosclerosis, la disfunción endotelial y la hipertensión arterial están estrechamente relacionadas. La vasorreactividad dependiente del endotelio es un equivalente de disfunción endotelial. OBJETIVO: evaluar la utilidad del diámetro basal de la arteria braquial medido por técnicas ultrasonográficas en el diagnóstico de disfunción endotelial como lesión vascular subclínica, su asociación con factores de riesgo cardiovascular y el riesgo cardiovascular global. MÉTODOS: investigación analítico transversal en 60 hipertensos de reciente diagnóstico sin lesión en órgano diana en comparación con 60 no hipertensos. Se pesquisaron los factores de riesgo cardiovascular, se les realizó microalbuminuria, colesterol total, colesterol HDL, triglicéridos, colesterol no HDL, medición por ultrasonografía del grosor íntima media carotídeo y del diámetro basal de la arteria braquial y se calculó el riesgo cardiovascular global. RESULTADOS: en el grupo de hipertensos, el sexo masculino constituyó el 55 % del total y en el de los no hipertensos, el sexo femenino representó el 78,3 %. La microalbuminuria estuvo presente en 25 % de los hipertensos por el 13,3 % de los no hipertensos. Se encontraron valores medios más altos de colesterol total y colesterol-no HDL en los hipertensos (4,6 mmol/L y 3,6 mmol/L, respectivamente). La media del grosor íntima media en los hipertensos fue 0,6 mm y la de los no hipertensos fue 0,4 mm. En los hipertensos, el valor medio de diámetro basal de la arteria braquial fue 3,8 mm frente a 3,5 mm en los no hipertensos. En ambos grupos de estudio, a mayores valores medios de colesterol-HDL, hubo mayores valores medios de diámetro basal de la arteria braquial. CONCLUSIONES: se encontró asociación positiva para el colesterol total, el colesterol-HDL, el grosor íntima media carotídeo, la microalbuminuria y el riesgo cardiovascular global con el diámetro basal de la arteria braquial. Se concluye que la determinación del diámetro basal de la arteria braquial mostró resultados promisorios como marcador de disfunción endotelial en la hipertensión arterial.


IINTRODUCTION: atherosclerosis, endothelial dysfunction and hypertension are closely related. Endothelium-dependent vasoreactivity is an equivalent of endothelial dysfunction. OBJECTIVE: To evaluate the usefulness of baseline diameter of the brachial artery measured by ultrasonographic techniques in the diagnosis of endothelial dysfunction and subclinical vascular lesion, its association with cardiovascular risk factors, and overall cardiovascular risk. METHODS: Across-sectional analytical research was conducted in 60 newly diagnosed hypertensive patients without target organ damage. They were compared with 60 non-hypertensive subjects. Cardiovascular risk factors were screened; these patients underwent several tests such as microalbuminuria, total cholesterol, HDL cholesterol, triglycerides, non-HDL cholesterol, ultrasound measurement of carotid intima-media thickness and basal diameter of the brachial artery. The global cardiovascular risk was calculated. RESULTS: In the hypertensive group, males constituted 55 % of the total and in the non-hypertensive group, females accounted for 78.3 %. Microalbuminuria was present in 25 % of hypertensive subejcts by 13.3 % of patients without the disease. Higher mean values of total cholesterol and non-HDL in hypertensive subjects (4.6 mmol / L and 3.6 mmol / L, respectively) were found. The mean intima-media thickness was 0.6 mm in hypertensive patients and 0.4 mm in non hypertensive subjects. In hypertensive patients, the mean baseline brachial artery diameter was 3.8 mm versus 3.5 mm in non-hypertensive subjects. In both study groups, higher mean levels of baseline diameter of the brachial artery when there were higher mean values of HDL-cholesterol. CONCLUSIONS: There is a positive association for total cholesterol, HDL-cholesterol, the carotid intima media thickness, microalbuminuria and global cardiovascular risk in basal diameter of the brachial artery. The determination of basal diameter of the brachial artery is concluded to show promising results as a marker of endothelial dysfunction in hypertension.


Subject(s)
Humans , Brachial Artery , Endothelial Cells , Hypertension/diagnosis , Early Diagnosis
9.
Braz. j. med. biol. res ; 47(10): 826-833, 10/2014. graf
Article in English | LILACS | ID: lil-722174

ABSTRACT

O-GlcNAcylation is a modification that alters the function of numerous proteins. We hypothesized that augmented O-GlcNAcylation levels enhance myosin light chain kinase (MLCK) and reduce myosin light chain phosphatase (MLCP) activity, leading to increased vascular contractile responsiveness. The vascular responses were measured by isometric force displacement. Thoracic aorta and vascular smooth muscle cells (VSMCs) from rats were incubated with vehicle or with PugNAc, which increases O-GlcNAcylation. In addition, we determined whether proteins that play an important role in the regulation of MLCK and MLCP activity are directly affected by O-GlcNAcylation. PugNAc enhanced phenylephrine (PE) responses in rat aortas (maximal effect, 14.2±2 vs 7.9±1 mN for vehicle, n=7). Treatment with an MLCP inhibitor (calyculin A) augmented vascular responses to PE (13.4±2 mN) and abolished the differences in PE-response between the groups. The effect of PugNAc was not observed when vessels were preincubated with ML-9, an MLCK inhibitor (7.3±2 vs 7.5±2 mN for vehicle, n=5). Furthermore, our data showed that differences in the PE-induced contractile response between the groups were abolished by the activator of AMP-activated protein kinase (AICAR; 6.1±2 vs 7.4±2 mN for vehicle, n=5). PugNAc increased phosphorylation of myosin phosphatase target subunit 1 (MYPT-1) and protein kinase C-potentiated inhibitor protein of 17 kDa (CPI-17), which are involved in RhoA/Rho-kinase-mediated inhibition of myosin phosphatase activity. PugNAc incubation produced a time-dependent increase in vascular phosphorylation of myosin light chain and decreased phosphorylation levels of AMP-activated protein kinase, which decreased the affinity of MLCK for Ca2+/calmodulin. Our data suggest that proteins that play an important role in the regulation of MLCK and MLCP activity are directly affected by O-GlcNAcylation, favoring vascular contraction.


Subject(s)
Animals , Male , Muscle, Smooth, Vascular/physiology , Myosin Light Chains/metabolism , Protein Processing, Post-Translational/physiology , Vasoconstriction/physiology , Aorta, Thoracic , Acetylglucosamine/analogs & derivatives , Acetylglucosamine/pharmacology , Acylation/drug effects , Acylation/physiology , Aminoimidazole Carboxamide/analogs & derivatives , Aminoimidazole Carboxamide/pharmacology , Azepines/pharmacology , Blotting, Western , Enzyme Inhibitors/pharmacology , Hypoglycemic Agents/pharmacology , Muscle, Smooth, Vascular/drug effects , Muscle, Smooth, Vascular/metabolism , Myosin-Light-Chain Kinase/metabolism , Myosin-Light-Chain Phosphatase/metabolism , Oxazoles/pharmacology , Oximes/pharmacology , Phenylcarbamates/pharmacology , Phenylephrine/agonists , Phosphorylation/drug effects , Phosphorylation/physiology , Rats, Wistar , Ribonucleotides/pharmacology , Vasoconstriction/drug effects , Vasoconstrictor Agents/pharmacology , beta-N-Acetylhexosaminidases/antagonists & inhibitors
10.
Braz. j. biol ; 74(3): 739-743, 8/2014. tab, graf
Article in English | LILACS | ID: lil-723895

ABSTRACT

Preliminary studies showed that dorsal artery contraction mediated by acetylcholine (ACh) is blocked with indomethacin in intertidal fish (Girella laevifrons). Our objective was to characterise the cholinergic pathway in several artery vessels of the G. laevifrons. Afferent and efferent branchial, dorsal and mesenteric arteries were dissected of 6 juvenile specimens, isometric tension studies were done using dose response curves (DRC) for Ach (10–13 to 10–3 M), and cholinergic pathways were obtained by blocking with atropine or indomethacin. CRC to ACh showed a pattern of high and low sensitivity. Furthermore, these contractions were blocked in the presence of atropine and indomethacin in all vessels. Our results suggest that contraction observed with acetylcholine is mediated by receptors that activate a cyclooxygenase contraction pathway.


Estudos preliminares mostraram que a contração da artéria dorsal mediada por acetilcolina (ACh) é bloqueada com indometacina em peixes marinhos Girella laevifrons. Nosso objetivo foi caracterizar a via colinérgica em várias artérias de G. laevifrons. Artérias aferentes e eferentes branquiais, dorsais e mesentéricas foram dissecadas de 6 espécimes juvenis. Os estudos de tensão isométrica foram feitos utilizando-se a curva dose - resposta (CDR) para Ach (10–13 a 10–3M), e identificaram-se as vias colinérgicas, bloqueando com atropina e indometacina. CRC para ACh mostrou um padrão de alta e baixa sensibilidade. Essas contrações foram bloqueadas na presença de atropina e indometacina em todas as artérias avaliadas. Nossos resultados sugerem que a contração observada com acetilcolina é mediada por receptores muscarínicos que ativam uma ciclo-oxigenase.


Subject(s)
Animals , Acetylcholine/pharmacology , Arteries/drug effects , Atropine/pharmacology , Cholinergic Agonists/pharmacology , Indomethacin/pharmacology , Perciformes/physiology , Arteries/physiology , Dose-Response Relationship, Drug , Perciformes/classification
11.
Braz. j. phys. ther. (Impr.) ; 18(1): 38-46, Jan-Feb/2014. tab, graf
Article in English | LILACS | ID: lil-704637

ABSTRACT

Objective: To investigate the blood pressure (BP) responses to cardiovascular stress test after a combined exercise circuit session at moderate intensity. Method: Twenty individuals (10 male/10 fem; 33.4± 6.9 years; 70.2± 15.8 kg; 170.4± 11.5 cm; 22.3± 6.8% body fat) were randomized in a different days to control session with no exercise or exercise session consisting of 3 laps of the following circuit: knee extension, bench press, knee flexion, rowing in the prone position, squats, shoulder press, and 5 min of aerobic exercise at 75-85% of age-predicted maximum heart rate and/or 13 on the Borg Rating of Perceived Exertion [scale of 6 to 20]. The sets of resistance exercise consisted of 15 repetitions at ~50% of the estimated 1 repetition maximum test. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured at rest and during 1h of recovery in both experimental sessions. After that, blood pressure reactivity (BPR) was evaluated using the Cold Pressor Test. Results: During 1h of exercise recovery, there was a reduction in SBP (3-6 mmHg) and DBP (2-5 mmHg) in relation to pre-session rest (p<0.01), while this reduction was not observed in the control session. A decline in BPR (4-7 mmHg; p<0.01) was observed 1h post-exercise session, but not in the control session. Post-exercise reductions in SBP and DBP were significantly correlated with BPR reductions (r=0.50-0.45; p<0.05). Conclusion: A combined exercise circuit session at moderate intensity promoted subsequent post-exercise hypotension and acutely attenuated BPR in response to a cardiovascular stress test. In addition, the post-exercise BP reduction was correlated with BPR attenuation in healthy adults of both genders. .


Subject(s)
Adult , Female , Humans , Male , Blood Pressure/physiology , Exercise Test/methods , Exercise/physiology , Stress, Psychological/physiopathology
12.
Braz. j. pharm. sci ; 50(2): 309-320, Apr-Jun/2014. tab, graf
Article in English | LILACS | ID: lil-722192

ABSTRACT

The aims of this study were to evaluate the chemical profile, vascular reactivity, and acute hypotensive effect (AHE) of the ethanolic extract of leaves of Alpinia purpurata (Vieill) K. Schum (EEAP). Its chemical profile was evaluated using HPLC-UV, ICP-OES, and colorimetric quantification of total flavonoids and polyphenols. The vascular reactivity of the extract was determined using the mesenteric bed isolated from WKY. AHE dose-response curves were obtained for both EEAP and inorganic material isolated from AP (IAP) in WKY and SHR animals. Cytotoxic and mutagenic safety levels were determined by the micronucleus test. Rutin-like flavonoids were quantified in the EEAP (1.8 ± 0.03%), and the total flavonoid and polyphenol ratios were 4.1 ± 1.8% and 5.1 ± 0.3%, respectively. We observed that the vasodilation action of EEAP was partially mediated by nitric oxide (·NO). The IAP showed the presence of calcium (137.76 ± 4.08 μg mg-1). The EEAP and IAP showed an AHE in WKY and SHR animals. EEAP did not have cytotoxic effects or cause chromosomic alterations. The AHE shown by EEAP could result from its endothelium-dependent vascular action. Rutin-like flavonoids, among other polyphenols, could contribute to these biological activities, and the calcium present in EEAP could act in a synergistic way.


Os objetivos deste estudo foram avaliar o perfil químico de folhas de Alpinia purpurata K. Schum (AP), assim como a reatividade vascular e o efeito hipotensor agudo (EHA) do extrato etanólico de folhas de AP (EEAP). Avliou-se o perfil químico utilizando-se HPLC-UV, ICP-OES e quantificação colorimétrica de flavonoides e polifenóis totais. A reatividade vascular foi determinada utilizando leito mesentérico isolado de ratos WKY. Curvas dose-resposta do EEAP e do material inorgânico da AP (IAP) foram realizadas em animais SHR e WKY. Determinaram-se a segurança citotóxica e mutagênica pelo teste de micronúcleos. Flavonoides tipo rutina foram quantificados no EEAP (1,8±0,03%) e flavonoide total e polifenóis foram de 4,1±1,8% e 5,1±0,3%, respectivamente. Observou-se ação vasodilatadora do EEAP, mediada parcialmente pelo óxido nítrico (·NO). O IAP revelou a presença de cálcio (137,76±4.08 μg.mg-1 de Ca). O EEAP e IAP apresentaram EHA em animais WKY e SHR. Não se observaram efeitos citotóxicos e alterações cromossômicas provocadas pelo EEAP. O EEAP mostrou um EHA que poderia resultar de ação vascular dependente do endotélio. Rutina, entre outros polifenóis e flavonoides, poderia estar contribuindo para essas atividades biológicas e o cálcio presente no EEAP, poderia agir de maneira sinérgica.


Subject(s)
Rats , Zingiberaceae/classification , Endothelium , Hypotension/prevention & control , Chromatography, High Pressure Liquid/classification , Reactivity-Stability , Polyphenols/analysis , International Classification of Primary Care
13.
Chinese Journal of Hepatobiliary Surgery ; (12): 604-608, 2014.
Article in Chinese | WPRIM | ID: wpr-457027

ABSTRACT

Objective To explore the role of hydrogen peroxide in mesenteric artery contraction of cirrhotic rats with portal hypertension,which was induced by bile duct ligation.Possible mechanism in RhoA/ROCK signal pathway was also part of the focus.Methods The bile duct ligation-induced cirrhotic rats and normal rats (control group) were treated equally with PEG-catalase(10 000 U/kg-1 · d-1,ip.) or by its vehicle for 8 days.Then the level of H2O2 in mesenteric arteries was detected.The contractile response to norepinephrine of arterioles was analyzed by vascular perfusion system.The protein expressions of the α1 adrenergic receptor,β-arrestin-2 and Rho kinase-1 (ROCK-1),and the activity of ROCK-1 were measured by western blot.In addition,the interaction of α1-adrenergic receptor with β-arrestin-2 was assessed by co-immunoprecipitation.Results Compared to normal rats,the dose-response curve of the mesenteric arterioles in response to norepinephrine shifted to the right,and the EC 50 increased in the rats with portal hypertension.PEG-catalase treatment can decrease the hydrogen peroxide level in arteries,thus significantly lowered EC50 and improved the reactivity to norepinephrine of the mesenteric arterioles in portal hypertension rats.No significant difference in the α1-adrenergic receptor amounts was observed among groups.There was remarkable decreases in the protein expressions of β-arrestin-2 and its interaction with the α1-adrenergic receptor in cirrhotic rats with PEG-catalase treatment.PEG-catalase also increased the amount and activity of ROCK-1 in cirrhotic rats.Conclusions The level of hydrogen peroxide increases in the mesenteric arteries in bile duct ligation-induced cirrhotic rats.And it enhances the β-arrestin-2 expression and its interaction with the α1-adrenergic receptor,which subsequently decreases the amount and activity of ROCK as well as the contractility of mesenteric arteries in response to vasoconstrictors.

14.
Braz. j. med. biol. res ; 46(7): 574-579, ago. 2013. tab, graf
Article in English | LILACS | ID: lil-682398

ABSTRACT

Vascular hyporeactivity is an important factor in irreversible shock, and post-shock mesenteric lymph (PSML) blockade improves vascular reactivity after hemorrhagic shock. This study explored the possible involvement of myosin light chain kinase (MLCK) in PSML-mediated vascular hyporeactivity and calcium desensitization. Rats were divided into sham (n=12), shock (n=18), and shock+drainage (n=18) groups. A hemorrhagic shock model (40±2 mmHg, 3 h) was established in the shock and shock+drainage groups. PSML drainage was performed from 1 to 3 h from start of hypotension in shock+drainage rats. Levels of phospho-MLCK (p-MLCK) were determined in superior mesenteric artery (SMA) tissue, and the vascular reactivity to norepinephrine (NE) and sensitivity to Ca2+ were observed in SMA rings in an isolated organ perfusion system. p-MLCK was significantly decreased in the shock group compared with the sham group, but increased in the shock+drainage group compared with the shock group. Substance P (1 nM), an agonist of MLCK, significantly elevated the decreased contractile response of SMA rings to both NE and Ca2+ at various concentrations. Maximum contractility (Emax) in the shock group increased with NE (from 0.179±0.038 to 0.440±0.177 g/mg, P<0.05) and Ca2+ (from 0.515±0.043 to 0.646±0.096 g/mg, P<0.05). ML-7 (0.1 nM), an inhibitor of MLCK, reduced the increased vascular response to NE and Ca2+ at various concentrations in the shock+drainage group (from 0.744±0.187 to 0.570±0.143 g/mg in Emax for NE and from 0.729±0.037 to 0.645±0.056 g/mg in Emax for Ca2+, P<0.05). We conclude that MLCK is an important contributor to PSML drainage, enhancing vascular reactivity and calcium sensitivity in rats with hemorrhagic shock.


Subject(s)
Animals , Male , Calcium/metabolism , Lymph/physiology , Mesenteric Artery, Superior/physiopathology , Muscle, Smooth, Vascular/physiopathology , Myosin-Light-Chain Kinase/physiology , Shock, Hemorrhagic/physiopathology , Muscle Contraction , Mesenteric Artery, Superior/metabolism , Muscle, Smooth, Vascular/metabolism , Myosin Light Chains/metabolism , Myosin-Light-Chain Kinase/analysis , Random Allocation , Rats, Wistar , Shock, Hemorrhagic/enzymology
15.
Clinics ; 67(7): 711-717, July 2012. graf, tab
Article in English | LILACS | ID: lil-645441

ABSTRACT

OBJECTIVE: To compare the effects of glimepiride and metformin on vascular reactivity, hemostatic factors and glucose and lipid profiles in patients with type 2 diabetes. METHODS: A prospective study was performed in 16 uncontrolled patients with diabetes previously treated with dietary intervention. The participants were randomized into metformin or glimepiride therapy groups. After four months, the patients were crossed over with no washout period to the alternative treatment for an additional four-month period on similar dosage schedules. The following variables were assessed before and after four months of each treatment: 1) fasting glycemia, insulin, catecholamines, lipid profiles and HbA1 levels; 2) t-PA and PAI-1 (antigen and activity), platelet aggregation and fibrinogen and plasminogen levels; and 3) the flow indices of the carotid and brachial arteries. In addition, at the end of each period, a 12-hour metabolic profile was obtained after fasting and every 2 hours thereafter. RESULTS: Both therapies resulted in similar decreases in fasting glucose, triglyceride and norepinephrine levels, and they increased the fibrinolytic factor plasminogen but decreased t-PA activity. Metformin caused lower insulin and pro-insulin levels and higher glucagon levels and increased systolic carotid diameter and blood flow. Neither metformin nor glimepiride affected endothelial-dependent or endothelial-independent vasodilation of the brachial artery. CONCLUSIONS: Glimepiride and metformin were effective in improving glucose and lipid profiles and norepinephrine levels. Metformin afforded more protection against macrovascular diabetes complications, increased systolic carotid artery diameter and total and systolic blood flow, and decreased insulin levels. As both therapies increased plasminogen levels but reduced t-PA activity, a coagulation process was likely still ongoing.


Subject(s)
Female , Humans , Male , Middle Aged , Carotid Arteries/drug effects , /drug therapy , Hypoglycemic Agents/pharmacology , Metformin/pharmacology , Sulfonylurea Compounds/pharmacology , Blood Glucose/metabolism , Carotid Arteries/pathology , /blood , Fasting/blood , Hypoglycemic Agents/therapeutic use , Lipids/blood , Organ Size/drug effects , Prospective Studies
16.
Rio de Janeiro; s.n; 2012. 103 p. tab.
Thesis in Portuguese | LILACS | ID: lil-658807

ABSTRACT

Introdução - O exercício resistido (ER) agudo parece resultar em importantes efeitos sobre a liberação de substâncias vasoativas e sobre o controle endotélio-dependente do tônus vascular. Objetivos - O objetivo do presente estudo foi avaliar os efeitos agudos de um ER isolado sobre a pressão arterial (PA), frequência cardíaca (FC), fluxo sanguíneo do antebraço (FSA), condutância vascular (CV), respostas endotelial e inflamatória de mulheres jovens com sobrepeso/obesidade (Sp/Ob). Materiais e Métodos - As voluntárias foram separadas em grupos: controle (n=16) e Sp/Ob (n=16). Ambos os grupos realizaram cinco séries de 10 repetições com 70% de uma repetição máxima (1-RM) no exercício de flexão unilateral do cotovelo. A PA, FC e o FSA (medido por pletismografia por oclusão venosa), foram avaliados em repouso e durante uma hora após o ER em ambos os grupos. Adipocitocinas e endotelina-1 (ET-1) foram avaliadas em repouso nos dois grupos e após o ER apenas no grupo Sp/Ob. Resultados - O grupo Sp/Ob apresentou massa corporal e IMC significativamente maiores que o controle (p<0,05). Surpeendentemente, o grupo Sp/Ob apresentou relação cintura-quadril significativamente menor (p<0,05). As diferenças entre grupos nas PAs diastólica e média observadas antes do ER (repouso) foram também observadas imediatamente e 20 minutos após a sessão de ER (p<0,05). Ambos os grupos apresentaram reduções significativas na PA diastólica imediatamente após a sessão de ER (p<0,01). A PA média apresentou redução significativa imediatamente após a sessão de ER apenas no grupo controle (p<0,05). O grupo Sp/Ob apresentou valores de FSA significatimentente maiores que o controle em repouso (p<0,05), em 20 (p<0,01) e em 40 (p<0,01) minutos após o ER. A CV apresentou diferença em repouso, porém em 20 e 40 minutos após o ER, o grupo Sp/Ob apresentou valores significativamente maiores (p<0,01). Em repouso e imediatamente após a sessão de ER, não foram observadas diferenças entre o grupo controle ...


Introduction - Acute resistance exercise (RE) seems to have important effects on release of vasoactive substances and on endothelium-dependet control of vascular tone. Objectives - The aims of our study were to the acute effects of an isolated RE on blood pressure (BP), heart rate (HR), forearm blood flow (FBF), vascular conductance (VC), endothelial and inflammatory responses of overweight/obese (Ow/Ob) young women. Materials and Methods - The volunteers were assigned in two groups: controls (n=16) and Ow/Ob (n=16). Both groups performed five sets of 10 repetitions with 70% of 1-RM in the unilateral elbow flexion exercise. BP, HR and FBF (determined by venous occlusion plethysmography) were evaluated at rest and along one hour after resistance exercise. Adipocytokines and endothelin-1 (ET-1) were evaluated at rest in both groups and after RE only in the Ow/Ob. Results - The Ow/Ob group presented significant higher body weight and BMI than controls. Of interest, the former group had significant lower waist-to-hip ratio (p<0.05). The significant differences between groups on diastolic and mean BP before resistance exercise (at resting) were observed immediately after and at 20 minutes post-exercise (P<0.05). Differences as a resultant of exercise in each group separately were noted and expressed as significant reduction in diastolic BP immediately post-exercise in both groups (p<0.01). Mean BP reduced immediately post-exercise only in controls (p<0.05). Significant higher basal FBF not only at resting (p<0.05) but also at 20 (p<0.01) and 40 minutes post-exercise (p<0.01) were evident in Ow/Ob group. Although basal FBF was different between groups at resting, basal VC was not. Of note, VC at 20 (p<0.01) and 40 minutes (p<0.01) post-exercise was higher in the Ow/Ob group compared to controls. At resting and immediately post-exercise, no differences between controls and Ow/Ob were observed in endothelial-dependent vasodilatation. We should emphasize ...


Subject(s)
Humans , Female , Adipokines/metabolism , Adipocytes/metabolism , Endothelium, Vascular/metabolism , Exercise/physiology , Arterial Pressure , Forearm/blood supply , Heart Rate , Obesity , Overweight , Regional Blood Flow , Resistance Training
17.
Braz. j. med. biol. res ; 44(9): 933-938, Sept. 2011. ilus
Article in English | LILACS | ID: lil-599668

ABSTRACT

Ouabain, an endogenous digitalis compound, has been detected in nanomolar concentrations in the plasma of several mammals and is associated with the development of hypertension. In addition, plasma ouabain is increased in several hypertension models, and the acute or chronic administration of ouabain increases blood pressure in rodents. These results suggest a possible association between ouabain and the genesis or development and maintenance of arterial hypertension. One explanation for this association is that ouabain binds to the α-subunit of the Na+ pump, inhibiting its activity. Inhibition of this pump increases intracellular Na+, which reduces the activity of the sarcolemmal Na+/Ca2+ exchanger and thereby reduces Ca2+ extrusion. Consequently, intracellular Ca2+ increases and is taken up by the sarcoplasmic reticulum, which, upon activation, releases more calcium and increases the vascular smooth muscle tone. In fact, acute treatment with ouabain enhances the vascular reactivity to vasopressor agents, increases the release of norepinephrine from the perivascular adrenergic nerve endings and promotes increases in the activity of endothelial angiotensin-converting enzyme and the local synthesis of angiotensin II in the tail vascular bed. Additionally, the hypertension induced by ouabain has been associated with central mechanisms that increase sympathetic tone, subsequent to the activation of the cerebral renin-angiotensin system. Thus, the association with peripheral mechanisms and central mechanisms, mainly involving the renin-angiotensin system, may contribute to the acute effects of ouabain-induced elevation of arterial blood pressure.


Subject(s)
Animals , Humans , Rats , Blood Pressure/drug effects , Cardiotonic Agents/pharmacology , Hypertension/chemically induced , Ouabain/pharmacology , Angiotensin II/biosynthesis , Calcium/metabolism , Cardiotonic Agents/administration & dosage , Cardiotonic Agents/metabolism , Central Nervous System/drug effects , Hypertension/metabolism , Injections, Intravenous , Norepinephrine , Ouabain/administration & dosage , Ouabain/metabolism , Peptidyl-Dipeptidase A/metabolism , Renin-Angiotensin System/drug effects , Sodium-Potassium-Exchanging ATPase/drug effects , Sodium-Potassium-Exchanging ATPase/physiology
18.
Braz. j. med. biol. res ; 44(9): 939-946, Sept. 2011.
Article in English | LILACS | ID: lil-599674

ABSTRACT

Heavy metals have been used in a wide variety of human activities that have significantly increased both professional and environmental exposure. Unfortunately, disasters have highlighted the toxic effects of metals on different organs and systems. Over the last 50 years, the adverse effects of chronic lead, mercury and gadolinium exposure have been underscored. Mercury and lead induce hypertension in humans and animals, affecting endothelial function in addition to their other effects. Increased cardiovascular risk after exposure to metals has been reported, but the underlying mechanisms, mainly for short periods of time and at low concentrations, have not been well explored. The presence of other metals such as gadolinium has raised concerns about contrast-induced nephropathy and, interestingly, despite this negative action, gadolinium has not been defined as a toxic agent. The main actions of these metals, demonstrated in animal and human studies, are an increase of free radical production and oxidative stress and stimulation of angiotensin I-converting enzyme activity, among others. Increased vascular reactivity, highlighted in the present review, resulting from these actions might be an important mechanism underlying increased cardiovascular risk. Finally, the results described in this review suggest that mercury, lead and gadolinium, even at low doses or concentrations, affect vascular reactivity. Acting via the endothelium, by continuous exposure followed by their absorption, they can increase the production of free radicals and of angiotensin II, representing a hazard for cardiovascular function. In addition, the actual reference values, considered to pose no risk, need to be reduced.


Subject(s)
Animals , Humans , Rats , Cardiovascular System/drug effects , Gadolinium/toxicity , Lead/toxicity , Mercury/toxicity , Adenosine Triphosphatases/chemistry , Cardiovascular Diseases/chemically induced , Endothelium, Vascular/drug effects , Free Radicals/chemistry , Free Radicals/metabolism , Metals, Heavy/poisoning , Poisoning , Risk Factors
19.
Braz. j. med. biol. res ; 44(4): 337-344, Apr. 2011. ilus, tab
Article in English | LILACS | ID: lil-581493

ABSTRACT

Androgenic anabolic steroid, physical exercise and stress induce cardiovascular adaptations including increased endothelial function. The present study investigated the effects of these conditions alone and in combination on the vascular responses of male Wistar rats. Exercise was started at 8 weeks of life (60-min swimming sessions 5 days per week for 8 weeks, while carrying a 5 percent body-weight load). One group received nandrolone (5 mg/kg, twice per week for 8 weeks, im). Acute immobilization stress (2 h) was induced immediately before the experimental protocol. Curves for noradrenaline were obtained for thoracic aorta, with and without endothelium from sedentary and trained rats, submitted or not to stress, treated or not with nandrolone. None of the procedures altered the vascular reactivity to noradrenaline in denuded aorta. In intact aorta, stress and exercise produced vascular adaptive responses characterized by endothelium-dependent hyporeactivity to noradrenaline. These conditions in combination did not potentiate the vascular adaptive response. Exercise-induced vascular adaptive response was abolished by nandrolone. In contrast, the aortal reactivity to noradrenaline of sedentary rats and the vascular adaptive response to stress of sedentary and trained rats were not affected by nandrolone. Maximum response for 7-10 rats/group (g): sedentary 3.8 ± 0.2 vs trained 3.0 ± 0.2*; sedentary/stress 2.7 ± 0.2 vs trained/stress 3.1 ± 0.1*; sedentary/nandrolone 3.6 ± 0.1 vs trained/nandrolone 3.8 ± 0.1; sedentary/stress/nandrolone 3.2 ± 0.1 vs trained/stress/nandrolone 2.5 ± 0.1*; *P < 0.05 compared to its respective control. Stress and physical exercise determine similar vascular adaptive response involving distinct mechanisms as indicated by the observation that only the physical exercise-induced adaptive response was abolished by nandrolone.


Subject(s)
Animals , Male , Rats , Adaptation, Physiological/drug effects , Anabolic Agents/pharmacology , Aorta, Thoracic/drug effects , Endothelium, Vascular/drug effects , Nandrolone/pharmacology , Adaptation, Physiological/physiology , Aorta, Thoracic/physiology , Endothelium, Vascular/physiology , Physical Conditioning, Animal/physiology , Rats, Wistar , Stress, Physiological/physiology
20.
International Journal of Traditional Chinese Medicine ; (6): 498-501, 2011.
Article in Chinese | WPRIM | ID: wpr-415898

ABSTRACT

Objective To investigate the effect of Chinese medicine Louxie mixture on vascular reactivity in atherosclerosis rats. Methods Forty male rats were randomly divided into four groups: the control group (A group, n=10) was fed with normal diet; the model group (B group, n=10), atorvastatin treated group (C group, n=10 and Louxie mixture group (D group, n=10) were fed with high fat/cholesterol diet. Atorvastatin 10 mg/kg·d-1 was administered to C group and Louxie mixture to D group for 10 weeks by gavages. Serum endothelin-1 (ET-1), nitric oxide (NO) and nitric oxide syntheses (NOS) were observed in different groups before and after the treatment. Vascular reactivity of aortic rings was measured by both the sodium nitroprusside(SNP)-induced endothelium-independent relaxation (NEDR) and the acetylcholine (Ach)-induced endothelium-dependent relaxation (EDR) in different groups. Results After treatment, the (19.03±1.72)μmol/l; NOS (24.78±0.25)U/ml vs (15.36±0.24U/ml), P<0.01], while the level of ET-1in B levels of NO and NOS in B group were significantly lower than those in A group [NO(35.73±3.72)μmol/l vs group was higher than that in A group [(34.58±4.00) pg/ml vs (117.58±5.34)pg/ml,P<0.01]. The levels of NO and NOS were significantly increased and the level of ET-1 was decreased in C and D groups after the treatment [NO(C: 31.30±1.96 umol/l;D: 32.85±3.70 umol/l); NOS (C: 21.96±1.07 U/ml ; D: 19.78± 1.20U/ml ); ET (C:58.26±5.14 pg/ml; D:59.30±5.73 pg/ml), P<0.01]. The activities of NEDR were similar in four groups[SNP Emax (A: 97.33±1.31; B: 98.24±1.04;C: 97.52±1.09; D: 97.91±1.59)%, P>0.05], but the level of EDR in the B group (P<0.01) was the lowest among four groups [Ach Emax (A: 72.65±3.31; B: 32.68±2.39;C: 61.63±2.07; D: 57.58±2.43)%, P<0.01]. Conclusion Chinese medicine Louxie mixture can protect vascular function in atherosclerosis rats.

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