Efeitos do treinamento físico associado à suplementação de L-arginina na resposta relaxante de artéria femoral de ratos
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Data
2009-08-10
Autores
Silva, Alexandre Sérgio [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O treinamento físico é considerado uma importante ferramenta no tratamento não farmacológico da hipertensão arterial por promover relaxamento vascular através de vários mecanismos. A L-arginina também tem sido relacionada a melhoria da função endotelial e vasorrelaxamento. No entanto, a influência do exercício físico e da Larginina na resposta vasodilatadora mediada pelos adrenoceptores β adrenérgicos vasculares ainda não está esclarecida O objetivo deste estudo foi investigar os efeitos de um programa de treinamento físico e da suplementação de L-arginina na reatividade vascular da artéria femoral de ratos Wistar. Animais com idade de 12 semanas foram randomicamente divididos em quatro grupos: sedentários (SD), treinados (TR), sedentários que suplementaram L-arginina (SD-ARG), e treinados que suplementaram L-arginina (TR-ARG). Os grupos treinados realizaram exercício de corrida em esteira durante um mês, cinco dias por semana, em sessões com duração de 60 minutos, e velocidade de 1,2 Km/h. Os grupos suplementados tiveram 1,25 g de L-arginina adicionado a cada litro da água de beber, pelo mesmo período do protocolo de treinamento físico. Quarenta e oito horas após o protocolo experimental, os animais foram sacrificados, e suas porções proximais da artéria femoral direita foram dissecadas e colocados em solução de Krebs-Ringer. Curvas concentração-efeito foram feitas para o isoproterenol (1nM – 10uM), após pré contração com fenilefrina (1 uM) em anéis íntegros ou desnudados de endotélio. Observou-se que a combinação de Treinamento físico e suplementação de Larginina, promoveu redução significativa do peso corporal dos animais, sem que treinamento ou suplementação isoladamente promovessem o mesmo efeito. A sensibilidade β-adrenérgica se mostrou significativamente reduzida com o treinamento físico, isoladamente ou associado...
Physical training is an important tool as a non pharmacological treatment of the arterial hypertension because of its several mechanisms which promote vasorelaxation. L-arginine is reported to improve either endothelial function or vascular relaxation. However, the influence of the physical exercise associated with L-arginine supplementation in the vascular relaxation mediated by vascular β adrenoceptores is not elucidated. The aim of this study was to investigate the effects of the physical training and L-arginine supplementation in the reactivity of femoral artery. Male Wistar rats (12 weeks old), were randomly separated in four groups: sedentary (SD), trained (TR), sedentary plus L-arginine supplementation (SD-ARG) and Trained plus L-arginine supplementation (TR-ARG). Physical exercise consisted in a running program in a motor-driven treadmill during 4 weeks, 5 days per week, 60 minutes per session, in a speed of 1.2 Km/h. Larginine was administered during 4 weeks in the drinking water (1.25 g/L), starting concomitantly with the exercise program. Animals were sacrificed 48 hours after the last session of exercise and the proximal segments of the femoral artery were removed and placed in Krebs-Ringer solution. Concentration–response curves were obtained to isoproterenol (1nM – 10uM), in rings with intact or denuded endothelium, precontracted with phenylephrine (1uM). The association of physical training and L-arginine supplementation resulted in a significant decrease in the body weight. However, physical training or L-arginine alone did not promote the same effect. The β-adrenergic receptors sensitivity was significantly decreased after physical training or L-arginine supplementation at the pEC50 level (SD: 7.13 ± 0.05; TR: 6.93 ± 0.03; SD-ARG: 7.22 ± 0.02; TR-ARG: 6.90 ± 0.01), with no changes in the maximal responses... (Complete abstract click electronic access below)
Physical training is an important tool as a non pharmacological treatment of the arterial hypertension because of its several mechanisms which promote vasorelaxation. L-arginine is reported to improve either endothelial function or vascular relaxation. However, the influence of the physical exercise associated with L-arginine supplementation in the vascular relaxation mediated by vascular β adrenoceptores is not elucidated. The aim of this study was to investigate the effects of the physical training and L-arginine supplementation in the reactivity of femoral artery. Male Wistar rats (12 weeks old), were randomly separated in four groups: sedentary (SD), trained (TR), sedentary plus L-arginine supplementation (SD-ARG) and Trained plus L-arginine supplementation (TR-ARG). Physical exercise consisted in a running program in a motor-driven treadmill during 4 weeks, 5 days per week, 60 minutes per session, in a speed of 1.2 Km/h. Larginine was administered during 4 weeks in the drinking water (1.25 g/L), starting concomitantly with the exercise program. Animals were sacrificed 48 hours after the last session of exercise and the proximal segments of the femoral artery were removed and placed in Krebs-Ringer solution. Concentration–response curves were obtained to isoproterenol (1nM – 10uM), in rings with intact or denuded endothelium, precontracted with phenylephrine (1uM). The association of physical training and L-arginine supplementation resulted in a significant decrease in the body weight. However, physical training or L-arginine alone did not promote the same effect. The β-adrenergic receptors sensitivity was significantly decreased after physical training or L-arginine supplementation at the pEC50 level (SD: 7.13 ± 0.05; TR: 6.93 ± 0.03; SD-ARG: 7.22 ± 0.02; TR-ARG: 6.90 ± 0.01), with no changes in the maximal responses... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Suplementos dieteticos, Exercícios físicos, Suplementação alimentar, Physical exercise, Supplementation
Como citar
SILVA, Alexandre Sérgio. Efeitos do treinamento físico associado à suplementação de L-arginina na resposta relaxante de artéria femoral de ratos. 2009. 83 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Rio Claro, 2009.