Efeito agudo do exercício resistido nas ações vasculares da insulina

• Autor(a) principal: Fontes, Milene Tavares
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: https://ri.ufs.br/handle/riufs/3868
• topic: Exercício resistido; Insulina; Óxido nítrico; Fosfatidilinositol 3-quinase; Reatividade vascular; Resistance exercise; Insulin; nitric oxide; Phosphatidylinositol-3-kinase; Vascular reactivity; CNPQ::CIENCIAS DA SAUDE

The aim of our study was to evaluate the effects of a resistance exercise session on the vascular action of insulin in superior mesenteric artery of rats. Wistar rats (250-300g) were divided into 3 groups: control (CT, n = 20), electrically stimulated (ES, n = 5) and resistance exercise (RE, n = 20). The exercise was conducted in the apparatus of the squat, where the animals were subjected to 15 sets of 10 repetitions with 3 minutes rest between sets. The intensity was set at 70% of maximum load established by repetition maximum test performed 48h before the exercise session. The animals were kept suspended in EE squat machine and received the same intensity of electrical stimuli applied to the exercised animals. Immediately after the single resistance exercise session, the animals were anesthetized and killed by exsanguination, the superior mesenteric artery was removed and sectioned into rings (1-2 mm) which were mounted on tanks for isolated organ. The endothelium-dependent relaxation was obtained from concentration-response curves for insulin on rings precontracted with phenylephrine. After that, concentration response curves were obtained for groups CT response and ER, in the absence and/or presence of the following inhibitors: L-NAME (NOS inhibitor), TEA (inhibitor nonselective channel for K+), LY294002 (PI3K inhibitor), BQ123 ( ETA receptor antagonist), and Ouabain (inhibitor of Na+/K+-ATPase), concentration-response curves to KCl in the absence and/or presence of ouabain. According to the data obtained, we found that there was no significant difference in the relaxation induced by insulin between groups EE and CT, however, the animals in the ER showed a significant increase in relaxation when compared to CT group (p<0.001). After use of L-NAME reducing the relaxation was observed in both groups (p<0.001). When evaluating the involvement of K + channels, using TEA, relaxation was inhibited only in the RE group (p <0.001). In the presence of L-NAME+TEA relaxation in the CT group was reduced and there was a group ER contraction (p<0.001). The presence of these rings LY294002 interestingly responded in similar ways in the presence of L-NAME+TEA, promoting and inhibiting the group CT contraction curve ER group (p<0.001). The BQ123 were able to amplify the relaxation in both groups (p<0.001). Using both inhibitors (LY294002+BQ123) was observed an inhibition of contractile and relaxing effects in both groups (p<0.001). To assess the functional activity of the Na+/K+-ATPase curves were made for insulin and KCl in the absence and presence of ouabain. It was observed that ouabain was a decrease of insulin-induced relaxation only in the ER (p<0.001) and reduced the relaxation promoted by KCl in both groups, this reduction being higher in the ER (p<0.001). These data demonstrate that a single session of resistance exercise promotes adjustments in insulin-induced relaxation, which is mediated by NO, the channels for K+ and the activity of Na+/K+-ATPase. In addition, there was an effect mediated by ET-1 (via ETA receptors), necessary for the control of vascular tone.