Abstract
Physical activity has been shown to enhance endothelial function of central and peripheral
vascular beds. The primary purpose of the present study was to test the hypothesis
that a short-term exercise training program would result in enhanced endothelium-dependent
vasorelaxation of a major artery supplying blood flow to the knee joint, the middle
genicular artery. Female Yucatan miniature swine were randomly assigned into exercise
trained (n=7) or sedentary (n=7) groups. Exercise trained pigs underwent a daily exercise
training program on treadmills for 7 days. In vitro assessment of vasorelaxation was
determined in a dose response manner by administrating increasing doses of 3 different
dilators; adenosine diphosphate, bradykinin, and sodium nitroprusside. The role of
nitric oxide synthase and cyclooxygenase pathways in vasomotor responses was evaluated
with specific inhibitors using nitro-L-arginine methyl ester and indomethacin incubation,
respectively. The results of this investigation indicate that adenosine and bradykinin-induced
endothelium-dependent vasorelaxation were significantly enhanced in middle genicular
artery from exercise trained pigs (p<0.05). Endothelium-independent vasorelaxation was not altered with exercise training
as determined by the response to sodium nitroprusside. The findings of the present
investigation indicate that short-term exercise training enhances endothelial function
of middle genicular artery through adaptations in the nitric oxide synthase and by
non-nitric oxide synthase, non-cyclooxygenase pathways.
Key words
physical activity - vasorelaxation - knee vasculature
