502 resultados para mean arterial pressure


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INTRODUCTION: Resistance training (RT) has been widely used for older adults in order to minimize or reverse the deleterious effects of aging in the neuromuscular system. However, the potential benefits of RT on arterial blood pressure and heart rate at rest in older adults remain controversial. OBJECTIVE: To analyze the effect of eight weeks of RT on systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and heart rate (HR) in older women without hypertension. METHODS: Seventeen women (aged 66.0 ± 5.8 years) without previous experience in RT were randomly assigned to either a training (TG, n = 10) or control (CG, n = 7) groups. Hemodynamic parameters at rest were evaluated by auscultatory method (mercury sphygmomanometer) and HR monitor (Polar), before and after eight weeks of experimental period. RESULTS: Reductions attributable to RT were found only to SBP (-13.4 mmHg, p <0.01). Although significant reductions were observed for DBP and MBP, the analysis of covariance showed no interaction Group x Time significant. CONCLUSION: RT proved an effective training to promote adaptations in the cardiovascular system of older women without hypertension. Eight weeks of RT can significantly reduce SBP at rest in older women.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The object of this study was assess through pre-clinical tests, the possible diuretic activity and the effects on the mean arterial pressure of the aqueous and ethanolic extracts of branches of “bugre”, Hedyosmum brasiliense Miq., species used in the treatment of renal and urinary disorders The tests were made in males anesthetized Wistar rats and randomly distributed into 4 experimental groups: Group I – Water control, group II – treated with aqueous extract (EA) of “bugre”, Group III – water control + “tween 80”, group IV – treated with ethanol extract (EE) and “bugre”. All groups were subjected to experimental protocol, composed of three periods: Balance (40 minutes), Basal (30 minutes) and Experimental (90 minutes), occurring the urine collection every 30 minutes, from the basal period and measuring blood pressure every 10 minutes. The results presented validate the ethnobotany indication of the use of H. brasiliense tea in the treatment of renal problems, because increased significantly the urinary flow in anesthetized Wistar rats (diuretic effect), without changing significantly (p>0,05) the arterial pressure

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The present experiments were conducted to investigate the role of the α1-, α2- and β-adrenergic receptors of the median preoptic area (MnPO) on the water intake and urinary electrolyte excretion, elicited by central injections of angiotensin II (ANG II). Prazosin (an α1-adrenergic receptor antagonist) and yohimbine (an α2-adrenergic receptor antagonist) antagonized the water ingestion, Na +, K +, and urine excretion induced by ANG II. Administration of propranolol, a β-adrenergic receptor antagonist increased the Na +, K +, and urine excretion induced by ANG II. Previous treatment with prazosin and yohimbine reduced the pressor responses to ANG II. These results suggest that the adrenergic neurotransmission in the MnPO may actively participate in ANG II-induced dipsogenesis, natriuresis, kaliuresis, diuresis and pressor responses in a process that involves α1-, α2-, and β-adrenoceptors.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Crotalus durissus cascavella is a snake that is usually found in the scrublands of northeast Brazil. The components of its venom may have effects on the vascular and renal systems. Recently, a new bradykinin inhibitory peptide has been identified in the venom of the Crotalinae family. The aim of the present study was to investigate the renal and vascular effects of the natriuretic peptide isolated from the venom of Crotalus durissus cascavella (NP2_Casca). The chromatographic profile showed the fractionation of substances identified as convulxin, gyroxin, crotoxin and crotamine, as well as fractions V and VI. The electrophoretic profile of fraction V consisted of several bands ranging from approximately 6 kDa to 13 kDa, while fraction VI showed only two main electrophoretic bands with molecular weights of approximately 6 and 14 kDa. Reverse-phase chromatography showed that NP2_Casca corresponds to about 18% of fraction VI and that this fraction is the main natriuretic peptide. NP2_Casca was compared to other natriuretic peptides from other sources of snake venom. All amino acid sequences that were compared showed a consensus region of XGCFGX, XLDRIX and XSGLGCX. The group treated with NP2-Casca showed an increase in perfusion pressure, renal vascular resistance, urinary flow and glomerular filtration rate. The percent of total and proximal tubular transport of sodium was reduced significantly after administration of the peptide. The mean arterial pressure showed a dose-dependent decrease after infusion of NP2_Casca, and an increase in nitrite production. In the aortic ring assay, NP2_Casca caused a relaxant effect in endothelium-intact thoracic aortic rings precontracted with phenylephrine in the presence and absence of isatin. NP2_Casca failed to relax the aortic rings precontracted with an isosmotic potassium Krebs-Henseleit solution. In conclusion, the natriuretic peptide isolated from Crotalus durissus cascavella venom produced renal and vascular effects. NP2_Casca reduced total and proximal sodium tubular transport, leading to an increase in sodium excretion, thereby demonstrating a diuretic action. A hypotensive effect was displayed in an arterial pressure assay, with an increase in nitrite production, suggesting a possible vasoactive action. (C) 2008 Elsevier Ltd. All rights reserved.

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Bothrops marajoensis is found in the savannah of Marajo Island in the State of Par S and regions of Amapa State, Brazil. The aim of the work was to study the renal and cardiovascular effects of the B. marajoensis venom and phospholipase A(2) (PLA(2)). The venom was fractionated by Protein Pack 5PW. N-terminal amino acid sequencing of sPLA(2) showed amino acid identity with other lysine K49sPLA(2)s of snake venom. B. marajoensis venom (30 mu g/mL) decreased the perfusion pressure, renal vascular resistance, urinary flow, glomerular filtration rate and sodium tubular transport. PLA(2) did not change the renal parameters. The perfusion pressure of the mesenteric bed did not change after infusion of venom. In isolated heart, the venom decreased the force of contraction and increased PP but did not change coronary flow. In the arterial pressure, the venom and PLA(2) decreased mean arterial pressure and cardiac frequency. The presence of atrial flutter and late hyperpolarisation reversed, indicating QRS complex arrhythmia and dysfunction in atrial conduction. In conclusion, B. marajoensis venom and PLA(2) induce hypotension and bradycardia while simultaneously blocking electrical conduction in the heart. Moreover, the decrease in glomerular filtration rate, urinary flow and electrolyte transport demonstrates physiological changes to the renal system. (C) 2009 Elsevier Ltd. All rights reserved.

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Objective: To determine the cardiovascular effects of desflurane in dogs following acute hemorrhage.Design: Experimental study.Animals: Eight mix breed dogs.Interventions: Hemorrhage was induced by withdrawal of blood until mean arterial pressure (MAP) dropped to 60 mmHg in conscious dogs. Blood pressure was maintained at 60 mmHg for 1 hour by further removal or replacement of blood. Desflurane was delivered by facemask until endotracheal intubation could be performed and a desflurane expiratory end-tidal concentration of 10.5 V% was maintained.Measurements and main results: Systolic, diastolic, and mean arterial blood pressure (SAP, DAP and MAP), central venous pressure (CVP), cardiac output (CO), stroke volume (SV), cardiac index (0), systemic vascular resistance (SVR), heart rate (HR), respiratory rate (RR), partial pressure of carbon dioxide in arterial blood (PaCO2), and arterial pH were recorded before and 60 minutes after hemorrhage, and 5, 15, 30, 45 and 60 minutes after intubation. Sixty minutes after hemorrhage, SAP, DAP, MAP, CVP, CO, Cl, SV, PaCO2, and arterial pH decreased, and HR and RR increased when compared with baselines values. Immediately after intubation, MAP and arterial pH decreased, and PaCO2 increased. Fifteen minutes after intubation SAP, DAP, MAP, arterial pH, and SVR decreased. At 30 and 45 minutes, MAP and DAP remained decreased and PaCO2 increased, compared with values measured after hemorrhage. Arterial pH increased after 30 minutes of desflurane administration compared with values measured 5 minutes after intubation.Conclusions: Desflurane induced significant changes in blood pressure and arterial pH when administered to dogs following acute hemorrhage.

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Objective: To evaluate the cardiorespiratory effects of continuous infusion of ketamine in hypovolemic dogs anesthetized with desflurane.Design: A prospective experimental study.Animals: Twelve mixed breed dogs allocated into 2 groups: saline (n=6) and ketamine (n=6).Interventions: After obtaining baseline measurements (time [T] 0) in awake dogs, hypovolemia was induced by the removal of 40 mL of blood/kg over 30 minutes. Anesthesia was induced and maintained with desflurane (1.5 minimal alveolar concentration) and 30 minutes later (T75) a continuous intravenous (IV) infusion of saline or ketamine (100 mu g/kg/min) was initiated. Cardiorespiratory evaluations were obtained 15 minutes after hemorrhage (T45), 30 minutes after desflurane anesthesia, and immediately before initiating the infusion (T75), and 5 (T80), 15 (T90), 30 (T105) and 45 (T120) minutes after beginning the infusion.Measurements and main results: Hypovolemia (T45) reduced the arterial blood pressures (systolic arterial pressure, diastolic arterial pressure [DAP] and mean arterial pressure [MAP]), cardiac (CI) and systolic (SI) indexes, and mean pulmonary arterial pressure (PAP) in both groups. After 30 minutes of desflurane anesthesia (T75), an additional decrease of MAP in both groups was observed, heart rate was higher than T0 at T75, T80, T90 and T105 in saline-treated dogs only, and the CI was higher in the ketamine group than in the saline group at T75. Five minutes after starting the infusion (T80), respiratory rate (RR) was lower and the end-tidal CO(2) (ETCO(2)) was higher compared with values at T45 in ketamine-treated dogs. Mean values of ETCO(2) were higher in ketamine than in saline dogs between T75 and T120. The systemic vascular resistance index (SVRI) was decreased between T80 and T120 in ketamine when compared with T45.Conclusions: Continuous IV infusion of ketamine in hypovolemic dogs anesthetized with desflurane induced an increase in ETCO(2), but other cardiorespiratory alterations did not differ from those observed when the same concentration of desflurane was used as the sole anesthetic agent. However, this study did not evaluate the effectiveness of ketamine infusion in reducing desflurane dose requirements in hypovolemic dogs or the cardiorespiratory effects of ketamine-desflurane balanced anesthesia.