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Oscillatory pulse pressure changes endothelial sensitivity to shear stress and myogenic tone in isolated mouse cerebral arteries
Author(s) -
Bolduc Virginie,
Colinas Olaia,
Lesage Frédéric,
Cole William C,
Thorin Eric
Publication year - 2013
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.27.1_supplement.700.12
Subject(s) - cerebral arteries , pulse pressure , endothelium , medicine , chemistry , cardiology , anatomy , blood pressure , constriction
Circulating blood travels in an oscillating waveform where the peak‐to‐peak amplitude is called the pulse pressure (PP) and the frequency is dictated by the heart rate. We investigated in vitro the impact of PP (amplitude: 30 mm Hg; rate: 550 beat per min) compared to static pressure (SP) on cerebral myogenic tone (MT) and endothelium‐dependent flow‐mediated dilation (FMD). Cerebral arteries (~160 μm diameter, n=5–9 per group) isolated and pressurized (80 mm Hg) from C57Bl6 (3‐mo) mice were used with or without a functional endothelium (eNOS inhibition by L‐NNA and endothelium removal). MT was magnified by PP compared to SP (20±3 vs. 6±2% reduction in diameter, p<0.05). L‐NNA (10 μM) and endothelium denudation increased MT under SP (25±3 and 14±3%, respectively, p<0.05) but not PP (25±3 and 13±4%, respectively). Under SP, arteries fully dilated at low shear stress (SS) to gradually re‐constrict at high SS (33±11% and 2±9% dilation at 4 and 20 dyn/cm2, respectively; p<0.05). In contrast, under PP, cerebral arteries gradually dilated at low to then lose tone and fully dilated at high SS (10±4 and 75±19% at 4 and 20 dyn/cm2, respectively; p<0.05). In conclusion, compared to static conditions, PP 1) increases MT that is insensitive to the endothelium and 2) suppresses flow‐mediated constriction at high SS. Supported by CIHR MOP89733.