Effects Of Exercise Training On Stress-induced Vascular Reactivity Alterations: Role Of Nitric Oxide And Prostanoids

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Background: Physical exercise may modify biologic stress responses. Objective: To investigate the impact of exercise training on vascular alterations induced by acute stress, focusing on nitric oxide and cyclooxygenase pathways. Method: Wistar rats were separated into: sedentary, trained (60-min swimming, 5 days/week during 8 weeks, carrying a 5% body-weight load), stressed (2 h-immobilization), and trained/stressed. Response curves for noradrenaline, in the absence and presence of L-NAME or indomethacin, were obtained in intact and denuded aortas (n=7-10). Results: None of the procedures altered the denuded aorta reactivity. Intact aortas from stressed, trained, and trained/stressed rats showed similar reduction in noradrenaline maximal responses (sedentary 3.54 +/- 0.15, stressed 2.80 +/- 0.10*, trained 2.82 +/- 0.11*, trained/stressed 2.97 +/- 0.21*, *P<0.05 relate to sedentary). Endothelium removal and L-NAME abolished this hyporeactivity in all experimental groups, except in trained/stressed rats that showed a partial aorta reactivity recovery in L-NAME presence (L-NAME: sedentary 5.23 +/- 0,26(#), stressed 5.55 +/- 0.38(#), trained 5.28 +/- 0.30(#), trained/stressed 4.42 +/- 0.41, P-#