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Decreased Arteriolar Sensitivity to Shear Stress in Adult Rats is Reversed by Chronic Exercise Activity
Author(s) -
Sun Dong,
Huang An,
Koller Akos,
Kaley Gabor
Publication year - 2002
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.1038/sj.mn.7800124
Subject(s) - sed , medicine , endocrinology , vasodilation , sodium nitroprusside , treadmill , endothelium , chemistry , cardiology , nitric oxide
Objective: We tested the hypothesis that the decline in endothelium‐dependent arteriolar dilation in adult rats is reversed by chronic exercise activity. Methods: Rats were divided into young (8–10 weeks)‐sedentary (SEDY), adult (29–32 weeks)‐sedentary (SEDA), and adult‐exercised (EXA, treadmill exercise for 18–20 weeks) groups. Responses of isolated arterioles (∼50 µm at 80 mm Hg) of gracilis muscle were assessed to increases in perfusate flow and vasoactive agents. Results: With no differences in basal tone, maximal flow‐induced dilations were not different between arterioles of SEDY and SEDA rats (71 ± 2 and 72 ± 2% of passive diameter, respectively), yet the sensitivity of arterioles to shear stress (WSS50) was significantly less in SEDA than in SEDY rats (35 ± 4 vs. 23 ± 3 dyne/cm 2 , respectively). In vessels of EXA rats, maximal flow‐induced dilation was significantly augmented (88 ± 2% of passive diameter) and WSS50 (15 ± 1 dyn/cm 2 ) was significantly reduced. Dilation to acetylcholine was enhanced in arterioles of EXA, whereas dilation to sodium nitroprusside was not different in vessels of the three groups. Conclusion: Chronic exercise activity reverses age related reduction in sensitivity of arterioles to increases in wall shear stress.