Abstract
Sex Differences in the Sympathetic Restraint of Skeletal Muscle Blood Flow in the Human Leg Vasculature
The FASEB journal, Vol.32(S1), pp.594.4-594.4
04/2018
DOI: 10.1096/fasebj.2018.32.1_supplement.594.4
Abstract
Background
The sympathetic nervous system plays an important role in regulating skeletal muscle blood flow at rest and during exercise. Previous studies have identified sex differences in resting muscle sympathetic nerve activity1 and forearm alpha‐adrenergic receptor sensitivity.2 However, whether sympathetic restraint of limb blood flow differs between sexes, and the degree to which this restraint persists during dynamic exercise, is not well understood.
Methods
In four young men (28±2 yrs; 26±2 kg/m2) and six young women (24±2 yrs; 23±1 kg/m2), we evaluated changes in leg blood flow (LBF, Doppler ultrasound), mean arterial blood pressure (MAP, indwelling femoral artery catheter), and leg vascular conductance (LVC) before and after intra‐arterial infusion of phentolamine (PHEN, non‐selective alpha‐adrenergic antagonist, 5 μg/dL/min) at rest and during small muscle mass knee‐extensor (KE) exercise (15W). Influences from beta‐adrenergic receptors were blocked by intravenous administration of propranolol (0.07 mg/kg bolus).
Results
No sex differences in LBF, MAP, or LVC were observed at rest. Following PHEN administration, sex differences were evident for both the drug‐induced increase in resting LBF (+337±79 vs. +172±43 mL/min, p<0.05, men vs. women) and LVC (+3.69±1.04 vs. +1.97±0.45 mL/min/mmHg, men vs. women, p=0.06). During KE exercise, no sex differences were evident for LBF, MAP, or LVC prior to PHEN infusion, and drug administration provoked similar increases in LBF (+630±128 vs. +560±85 mL/min, men vs. women) and LVC (+7.2±1.5 vs. +6.9±1.6 mL/min/mmHg, men vs. women) between groups.
Conclusion
At rest, men demonstrate a larger increase in LBF and LVC in response to local alpha adrenergic receptor blockade via PHEN infusion, suggesting a greater degree of basal sympathetic vasoconstriction than their female counterparts. However, during exercise, similar increases in leg hemodynamics were observed between men and women following PHEN administration. Together, these data support the presence of a sex difference in the sympathetic restraint of resting limb blood flow that does not persist during moderate intensity exercise.
Support or Funding Information
This project is funded in part by the National Institutes of Health (HL118313) and the U.S. Department of Veterans Affairs (RX001697, RX001418, E6910R).
This is from the Experimental Biology 2018 Meeting. There is no full text article associated with this published in The FASEB Journal.
Details
- Title: Subtitle
- Sex Differences in the Sympathetic Restraint of Skeletal Muscle Blood Flow in the Human Leg Vasculature
- Creators
- Kanokwan Bunsawat - Geriatric Research Education and Clinical CenterStephen M. Ratchford - Geriatric Research Education and Clinical CenterHeather L. Clifton - University of UtahJeremy K. Theisen - University of UtahZachary Barrett-O'Keefe - University of UtahRyan M. Broxterman - Geriatric Research Education and Clinical CenterJayson R. Gifford - University of UtahJay Hydren - University of UtahMatthew J. Rossman - University of UtahStephen J. Ives - University of UtahJoel D. Trinity - University of UtahMelissa A.H. Witman - University of UtahRyan S. Garten - University of UtahDavid E. Morgan - University of UtahAshley D. Nelson - Geriatric Research Education and Clinical CenterRussell S. Richardson - University of UtahD. Walter Wray - University of Utah
- Resource Type
- Abstract
- Publication Details
- The FASEB journal, Vol.32(S1), pp.594.4-594.4
- DOI
- 10.1096/fasebj.2018.32.1_supplement.594.4
- ISSN
- 0892-6638
- eISSN
- 1530-6860
- Publisher
- The Federation of American Societies for Experimental Biology
- Number of pages
- 1
- Grant note
- National Institutes of Health (HL118313) U.S. Department of Veterans Affairs (RX001697; RX001418; E6910R)
- Language
- English
- Date published
- 04/2018
- Academic Unit
- Health, Sport, and Human Physiology
- Record Identifier
- 9984958629902771
Metrics
1 Record Views