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The Effect of Exercise Training on Sympathetic Vasoconstrictor Responsiveness and Sympatholysis in Female Rats
Author(s) -
DeLorey Darren S.,
Just Timothy P.,
Cooper Ian R.,
Liu Sixue
Publication year - 2018
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.2018.32.1_supplement.855.2
Subject(s) - medicine , aerobic exercise , vasoconstriction , stimulation , sympathetic nervous system , endocrinology , endurance training , physical exercise , cardiology , blood pressure
Our laboratory has previously reported that aerobic exercise training enhances contraction‐mediated inhibition of sympathetic vasoconstriction (sympatholysis) in male rats. Whether aerobic exercise training has a similar effect in female rats has not been established. Therefore, the purpose of the present study was to investigate the hypothesis that aerobic exercise training would blunt sympathetic vasoconstrictor responsiveness and enhance sympatholysis in female rats. Female Sprague‐Dawley rats were randomly assigned to sedentary (n=10) or treadmill exercise training (n=8) groups (15 min at 40 m/min, 5% gradient; 5 d/week) for 10 weeks. Following the completion of the sedentary behavior or exercise training intervention, rats were anaesthetized and instrumented for stimulation of the lumbar sympathetic chain and the measurement of arterial blood pressure and femoral vascular conductance (FVC). The triceps surae muscle group was stimulated to contract rhythmically at 60% of maximal contractile force. The percentage change of FVC (Δ%FVC) in response to sympathetic stimulation delivered at 2 and 5 Hz was determined at rest and during contraction. At rest, sympathetic vasoconstrictor responsiveness (Δ%FVC) was not different (p>0.05) between sedentary and exercise trained rats in response to sympathetic stimulation delivered at 2Hz (Sedentary: −39 ± 12 %; Exercise Trained: −45 ± 9 %) and 5Hz (Sedentary: −57 ± 8 %; Exercise Trained: −61 ± 9 %). Muscle contraction blunted (p<0.05) sympathetic vasoconstrictor responsiveness in both sedentary and exercise trained rats and the magnitude of sympatholysis was not different (p>0.05) between sedentary (2Hz: 24 ± 8 %; 5Hz: 29 ± 10 %) and exercise‐trained (2Hz: 30 ± 10 %; 5Hz: 29 ± 13 %) rats. These data demonstrate that aerobic exercise training does not alter sympathetic vasoconstrictor responsiveness or contraction mediated inhibition of sympathetic vasoconstriction (sympatholysis) in female rats. Further investigation is required to determine why female rats respond differently to exercise training than male rats. Support or Funding Information Natural Sciences and Engineering Research Council of Canada, Canadian Foundation for Innovation, and Alberta Advanced Education and Technology. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .