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THE EXERCISE‐INDUCED PERIPHERAL COLLATERAL BLOOD FLOW ADAPTATION APPEARS SELF‐LIMITING.
Author(s) -
Yang Hsiao Tung,
Prior Barry M,
Terjung Ronald L
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a574-c
Subject(s) - medicine , limiting , blood flow , collateral circulation , occlusion , treadmill , cardiology , anatomy , peripheral , mechanical engineering , engineering
To study whether a 14 wks training program to exaggerate the flow stimulus by running would increase collateral dependent blood flow (CDBF) above the level reported previously with a 4 wks running protocol, adult female rats with occluded femoral arteries were exercised (TrOccl; n=13) daily for up to >6 hr/d (2 bouts/d at 20 m/min over 14 wks) or kept sedentary (cage activity; SedOccl; n=9), and CDBF of calf muscles were compared to that of normal (NOR; n=6) or acute occluded (AcuteOccl; n=6) animals. BFs to the calf muscles were measured with isotope labeled microspheres during treadmill running. Collateral vessels were isolated and mounted on glass pipettes for determination of pressure/diameter relationships. CDBF to the calf muscle of the TrOccl animals (100±5.0 ml/min/100g) was markedly greater than that of SedOccl (57±2.0) which was greater than that observed with AcuteOccl (21±3.0), but well less than that found in the absence of occlusion (NOR; 167±8.4) (p<0.001). Increases in collateral vessel size with training (57%) and occlusion (26%) (p<0.001) were similar to that observed previously with 4 wks training. Further, the ratio of CDBF/normal BF in calf muscle was only about 11% higher in 14 wks than 4 wks trained animals. These findings imply that the stimulus for collateral vessel enlargement and increase in BF with daily exercise leads to a self‐limiting process, since the exaggerated history of flow stimulus through the collateral vessels did not produce further vascular adaptations. Supported by NIH grant HL 37387