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Estrogen and sympathetic modulation of hindlimb blood flow variability in rats
Author(s) -
Mattar Louis,
Noble Earl,
Shoemaker J. Kevin
Publication year - 2010
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.24.1_supplement.1039.13
Subject(s) - hindlimb , ovariectomized rat , endocrinology , medicine , estrogen , blood flow , coefficient of variation , hexamethonium , biology , chemistry , atropine , chromatography
Recent evidence suggests that males and females rely on different physiologic mechanisms to maintain blood flow and vasculature conductance. To test the hypothesis that sympathetic inputs affect hindlimb flow variability, the coefficient of variation (CV = standard deviation/mean) of hindlimb flow and conductance were measured in male and female animals of various rat strains (Sprague Dawley, Spontaneously Hypertensive and Wistar‐Kyoto). One thousand consecutive heart beats at baseline and during sympathectomy (25mg/kg Hexamethonium; Hex) were used to assess each CV. Female rats (any strain) exhibited greater CV in hindlimb conductance at baseline compared to males (grouped gender averages: 35±19AU vs. 12±11AU, respectively; P<0.05 ). A subgroup of female hypertensive animals that were ovariectomized (OVX) exhibited lower CV (25±21AU) compared to their intact counterparts (41±14AU; P<0.05 ), and OVX animals given estrogen (51±22AU; P<0.05) . The variability in female animals was driven by changes in hindlimb flow, and was blunted (i.e. not different from males) following Hex (19±13AU vs. 10±6AU, n.s. between female and male animals respectively). Therefore, blood flow variability was greater in the hindlimb of female rats of various strains and this variability was related to both estrogen and sympathetic mechanisms. Supported by CIHR.