Voluntary physical exercise-induced vascular effects in spontaneously hypertensive rats

• Forced training has been shown to have beneficial vascular effects in various animal exercise models. In the present study, we explored possible physiological and molecular effects of voluntary physical exercise on various vascular beds. SHR (spontaneously hypertensive rats) performed voluntary exercise for 5 weeks in a computerized wheel cage facility. Ex vivo myograph studies revealed an increased sensitivity of the ACh (acetylcholine)-mediated vasodilation in resistance arteries of the exercised animals (ED50=15.0+/-3.5 nmol/l) compared with the controls (ED50=37.0+/-8.8 nmol/l; P=0.05). The exercise/control difference was abolished after scavenging reactive oxygen radicals. In conduit arteries, ACh induced a similar vasodilatory response in both groups. The in vivo aortic wall stiffness, assessed by means of Doppler tissue echography, was significantly lower in the exercising animals than in controls. This was demonstrated by significantly increased peak systolic aortic wall velocity (P=0.03) and the velocity time integral (P=0.01) in exercising animals compared with controls. The relative gene expression of eNOS (endothelial nitric oxide synthase) was similar in both groups of animals, whereas Cu/ZnSOD (copper/zinc superoxide dismutase) gene expression was significantly increased (+111%; P=0.0007) in the exercising animal compared with controls. In conclusion, voluntary physical exercise differentially improves vascular function in various vascular beds. Increased vascular compliance and antioxidative capacity may contribute to the atheroprotective effects associated with physical exercise in conduit vessels.

Nyckelord

Animals

Aorta

Thoracic/physiopathology/ultrasonography

Blood Pressure

Body Weight

Echocardiography

Doppler/methods

Endothelium

Vascular/*physiopathology

Exertion

Gene Expression Regulation

Enzymologic

Hypertension/metabolism/pathology/*physiopathology

Mesenteric Arteries/physiopathology

*Motor Activity

Myocardium/pathology

Nitric Oxide/physiology

Nitric Oxide Synthase/genetics/metabolism

Organ Size

Rats

Rats

Inbred SHR

Superoxide Dismutase/genetics/metabolism

Vasodilation

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)