Physical conditioning decreases norepinephrine-induced vasoconstriction in rabbits. Possible roles of norepinephrine-evoked endothelium-derived relaxing factor

H I Chen, H T Li, C C Chen
1994 Circulation  
Physical activity can reduce sympathetic tone and may be beneficial to human health. Whether the vascular responses to norepinephrine (NE), an adrenergic vasoconstrictor, could be altered by chronic exercise was unclear. We therefore conducted this study to investigate the effects of endurance exercise training on NE-induced vasoconstrictive response in healthy rabbits. Possible mechanisms were also studied. Methods and Results Twenty-four male New Zealand White rabbits were used for this
more » ... They were divided into two groups: control and training. The training group was trained on a treadmill with running speed of 0.88 km/h at a 00 grade for 10 to 60 minutes per day, for 5 days a week for a total of 8 weeks. At the end of the experiments, thoracic aortae (3 mm long) were isolated. The vascular tension was measured with a force transducer. The dose-response relation of NEinduced vasoconstriction was determined and compared for control (n=5) and trained (n=6) groups. To verify the possible involvement of endothelium-derived relaxing factor (EDRF) in the alteration of NE-induced vasoconstriction after exercise training, we compared the vascular responses to NE in endo-
doi:10.1161/01.cir.90.2.970 pmid:8044969 fatcat:isjc7atld5h57li5vsx6wqj7pe