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Obesity‐Associated Impairments in Autonomic Control of Blood Pressure and Heart Rate are Sex‐Specific
Author(s) -
BruderNascimento Thiago,
Ekeledo Obioma J.,
Anderson Ruchi,
Le Huy B.,
Belin de Chantemele Eric J.
Publication year - 2016
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.30.1_supplement.738.5
Subject(s) - medicine , endocrinology , blood pressure , heart rate , obesity , leptin , diastole , body mass index , brown adipose tissue
Body weight gain induces cardiovascular disease by increasing sympathetic activity in males. Whether increasing body mass similarly affects autonomic control of cardiovascular function in males and females is unknown. Based on the evidence that sympathetic tone is lower in lean females than males, we tested the hypothesis that obesity‐associated impairments in autonomic control of blood pressure and heart rate are sex‐specific. Male and female C57Bl/6 mice were submitted to either a control (CD) or a high fat diet (HFD) for 24 weeks to induce obesity. Female mice gained more adipose mass and lost more lean mass compared to males. However, male and female mice reached a similar body weight (male: 51±8 vs. female: 48±8 g, NS.) at the end of the diet. HFD induced a similar and significant increase in plasma leptin, insulin, glucose, cytokines and lipids levels in male and female mice. Measurement of blood pressure (BP) and heart rate (HR) in conscious mice revealed that HFD did not elevate systolic, diastolic or mean arterial pressure (male CD: 122±6, HFD: 116±6 vs. female CD: 115±4 vs. HFD: 110±3 mmHg), but significantly increased HR in males (CD: 571±9, HFD: 631±14, P<0.05) and females (CD: 589±19 vs. HFD: 642±6, P<0.05). Indexes of autonomic control of BP and HR were obtained by measuring BP and HR response to ganglionic blocker, and to β‐adrenergic and muscarinic receptor antagonists. These experiments conducted in conscious animals revealed that HFD increased vascular sympathetic drive in male (CD: −43±4 and HFD: −60±7% drop in BP, P<0.05) but not female mice (CD: −37±4% and HFD: −40±4% drop in BP, NS). Consistent with the concept that increasing sympathetic tone reduces vascular adrenergic reactivity, HDF specifically reduced aortic α‐adrenergic constriction in male mice. Aortic α‐adrenergic reactivity remained intact in HFD females. In both sexes, aortic constrictions to serotonin or potassium chloride, and endothelium‐dependent and independent relaxations remained preserved. HFD reduced HR response to β‐adrenergic blockade in both sexes, suggestive of a reduction in cardiac sympathetic tone. HFD lowered HR response to muscarinic receptor blockade in females only, indicative of a reduced vagal tone. All together these data suggest that obesity‐associated increases in HR is likely caused by a decrease in vagal tone in female mice, while the increased in HR in males might be a mechanism to preserve BP and compensate for the reduced vascular adrenergic reactivity.