Exercise training improves aortic endotheliumdependent vasorelaxation and determinants of nitric oxide bioavailability in spontaneously hypertensive rats

rats. J Appl Physiol 96: 2088–2096, 2004. First published January 29, 2004; 10.1152/japplphysiol.01252.2003.—The present study exam-ined in vitro vasomotor function and expression of enzymes control-ling nitric oxide (NO) bioavailability in thoracic aorta of adult male normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) that either remained sedentary (Sed) or performed 6 wk of moderate aerobic exercise training (Ex). Training efficacy was con-firmed by elevated maximal activities of both citrate synthase (P 0.0024) and -hydroxyacyl-CoA dehydrogenase (P 0.0073) in the white gastrocnemius skeletal muscle of Ex vs. Sed rats. Systolic blood pressure was elevated in SHR vs. WKY (P 0.0001) but was not affected by Ex. Despite enhanced endothelium-dependent relaxation to 108 M ACh in SHR vs. WKY (P 0.0061), maximal endothe-lium-dependent relaxation to 104 M ACh was blunted in Sed SHR (48 12%) vs. Sed WKY (84 6%, P 0.0067). Maxima