The dynamic adjustment and amplitude of the endothelium-dependent vasorelaxation of the carotid, aorta, iliac and femoral vessels were measured in response to acute low- (LI) or high-intensity (HI) endurance exercise. Vasorelaxation to 10-4 M ACh (ACh) was evaluated in 10 control, 10 LI, and 10 HI rats. Two mm sections of carotid, aorta, iliac, and femoral arteries were mounted onto a myography system. Vasorelaxation responses were modeled as a mono-exponential function. The overall τ (Control, 10.5±6.0 s; LI, 10.4±5.7 s; HI, 11.0±6.9 s) and time-to-steady-state (Control, 47.6±24.0 s; LI, 46.2±22.8 s; HI, 49.1±28.3 s) was similar in LI, HI and control (p>0.05). The overall (average of four vessel-type) % vasorelaxation was larger in LI (73±16%) and HI (73±16%) than in control (66±19%) (p<0.05). The overall rate of vasorelaxation was greater in LI (1.9±0.9%∙s-1) and HI (1.9±1.1%∙s-1) compared to control (1.6±0.7%∙s-1) (p<0.05). The vessel-specific responses (average response for the three conditions) showed that carotid displayed a slower adjustment (τ, 18.9±4.4 s; time-to-steady-state, 80.4±18.4 s) compared to the aorta (τ, 10.3±3.8 s; time-to-steady-state, 46.3±15.2 s), the iliac (τ, 6.3±2.1 s; time-to-steady-state, 30.3±9.0 s), and the femoral (τ, 6.0±1.9 s; time-to-steady-state, 29.3±8.4 s). The % vasorelaxation was larger in the carotid (82±14%) than in the aorta (67±16%), iliac (61±13%), and femoral (71±19%) (p>0.05). The rate of vasorelaxation was: carotid (1.1±0.2%∙s-1), aorta (1.5±0.4%∙s-1), iliac (2.2±0.8%∙s-1), and femoral (2.6±1.0%∙s-1). In conclusion, an acute bout of endurance exercise increased vascular responsiveness. The dynamic and percent adjustments were vessel-specific with vessel function likely determining the response.
- endothelium-dependent vasorelaxation
- vessel myography
- vascular responsiveness
- vascular kinetics
- Copyright © 2012, American Journal of Physiology - Regulatory, Integrative and Comparative Physiology