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Effects of nitric oxide synthase inhibitor on decrease in peripheral arterial stiffness with acute low-intensity
Jun Sugawara1, Seiji Maeda, Takeshi Otsuki
1Center for Tsukuba Advanced Research Alliance, Univ. of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8574, Japan.
Summary
Low-intensity aerobic exercise reduces arterial stiffness, but this effect is not primarily due to nitric oxide (NO) production. Blocking NO synthase did not prevent the exercise-induced decrease in arterial stiffness.
Area of Science:
- Cardiovascular Physiology
- Exercise Science
- Vascular Biology
Background:
- Acute aerobic exercise, even at low intensity and short duration, has been shown to decrease arterial stiffness.
- The precise physiological mechanisms underlying this exercise-induced reduction in arterial stiffness require further investigation.
Purpose of the Study:
- To test the hypothesis that exercise-induced decreases in arterial stiffness are mediated by increased nitric oxide (NO) production in the vascular endothelium.
- To investigate the role of NO in the acute reduction of regional arterial stiffness following low-intensity aerobic exercise.
Main Methods:
- Nine healthy young men performed 5-minute single-leg cycling exercises under conditions of either NG-monomethyl-L-arginine (L-NMMA) infusion to block NO synthase or a saline vehicle control.
- Pulse wave velocity (PWV) was measured in both legs before and after infusion, at rest, and post-exercise.
- Statistical analysis examined the effects of L-NMMA administration and exercise on PWV in the exercised and non-exercised legs.
Main Results:
- In the control condition, exercised leg PWV significantly decreased post-exercise, while the non-exercised leg showed no significant change.
- Under L-NMMA administration, exercised leg PWV initially increased but then significantly decreased post-exercise.
- Non-exercised leg PWV increased with L-NMMA and remained elevated, but the interaction between NO synthase blockade and time on exercised leg PWV was not significant.
Conclusions:
- Increased production of nitric oxide (NO) is not a primary factor responsible for the reduction in regional arterial stiffness observed after low-intensity, short-duration aerobic exercise.
- The findings suggest that other mechanisms contribute to the acute vascular adaptations following exercise.
- Further research is needed to elucidate the specific pathways mediating exercise-induced arterial stiffness reduction.