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Pressure dependence of reactive and agonist‐induced dilation
Author(s) -
Gray Eric Jason,
Carter Matthew R.,
Jasperse Jeffrey L.
Publication year - 2011
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.25.1_supplement.1108.9
Subject(s) - reactive hyperemia , dilation (metric space) , cardiology , forearm , medicine , chemistry , vasodilation , anatomy , mathematics , geometry
The magnitude of forearm reactive hyperemia is related to occlusion duration and arm position, suggesting both a metabolic and a myogenic component. We tested the hypothesis that reactive dilation is dependent on both the magnitude and duration of pressure reduction. Rat soleus feed arteries (n=12) were isolated, cannulated, and baseline pressure was set at either 65 or 115 cmH2O to mimic feed artery pressure in the arm in above and below heart positions. Pressure was reduced to 14 cmH2O from either baseline pressure for 30s or 1, 2, or 5 min. Both increasing duration and baseline pressure increased the magnitude of dilation (30s‐65 = 19.6±5.1, 30s‐115 = 22.1±5.4, 1m‐65 = 20.4±4.2, 1m‐115 = 34.3±5.4, 2m‐65 = 28.5±5.6, 2m‐115 = 47.8±7.5, 5m‐65 = 47.4±7.6, 5m‐115 = 63.6 ± 7.5 % dilation). We then performed pressure reductions of equal magnitude from each baseline pressure: 65 to 14 cmH2O and 115 to 64 cmH2O. Reactive dilation was similar at both baseline pressures when the magnitude of pressure reduction was equal (18.3±6.0 vs. 20.2±5.5 at 30s, 19.5±5.2 vs. 22.0±5.0 at 1m, and 27.3±7.7 vs. 30.4±8.2 at 2m). ACh induced dilation was also similar at both baseline pressures. These data indicate that dilation after a period of reduced pressure is enhanced by both increased duration and increased magnitude of the pressure reduction, suggesting that reactive hyperemia is partially dependent on myogenic properties of the vasculature.