Aims: We evaluated the acute effects of different intensities of resistance exercise over endothelium-dependent vasodilatation, eNOSser1177 phosphorylation level and endothelial production of NO in superior mesenteric artery of healthy rats.
Main methods: Groups: control (Ct), resistance exercise in the intensities of 30% (Ex30%), 50% (Ex50%) and 70% (Ex70%) of the maximal load established by the maximal repetition test (1RM). Exercise protocol: 15 sets of 10 repetitions. The rings of mesenteric artery were mounted in an isometric system or were prepared for further implementation of Western blot and DAF-FM techniques.
Key findings: The maximal response of the relaxation induced by insulin was not altered in the animals of the Ex30% group when compared to the Ct group. However, the animals of the Ex50% and Ex70% groups presented an increase in this response when compared to the Ct group. The eNOSser1177 phosphorylation levels showed an increase in Ex50% and Ex70% groups when compared to the Ct (1.6-fold and 3.3-fold, respectively). In the endothelial production of NO, it was observed that the Ex30% group did not show alteration in the NO production when compared to the Ct group. On the other hand, the animals exercised in the Ex50% and Ex70% groups showed increase in the NO synthesis when compared to the animals in the Ct group.
Significance: Our results suggest that the magnitude of these vascular endothelium adjustments is strongly related to the increase of the resistance exercise intensity from the intensity of 50% of 1 RM.
Keywords: ENOS; Nitric oxide; Vasorelaxation.