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The role played by oxidative stress in evoking the exercise pressor reflex in health and simulated peripheral artery disease
Author(s) -
Harms Jonathan E,
Kim Joyce S,
Kuczmarski J Matthew,
Thomas Gail D,
Kaufman Marc P
Publication year - 2017
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.31.1_supplement.712.7
Subject(s) - tiron , femoral artery , medicine , reflex , endocrinology , superoxide , vasoconstriction , anatomy , anesthesia , chemistry , biochemistry , enzyme
Contraction of skeletal muscle evokes the exercise pressor reflex (EPR), which is expressed in part by increases in heart rate and arterial pressure. Patients with peripheral artery disease (PAD) show an exaggerated EPR, sometimes report pain when walking and have an increased risk for cardiac arrthymias. Previous research has suggested that reactive oxygen species (ROS) mediate the exaggerated EPR associated with PAD. To examine the effects of ROS on the exercise pressor reflex, we infused a superoxide scavenger, Tiron, into the superficial epigastric artery of decerebrated rats. In some of these rats, we simulated PAD by ligating a femoral artery for 72 hours before the experiment. The peak EPR in ligated rats during saline infusion into the superficial epigastric artery averaged 31 ± 4 mmHg; n=12), whereas the peak EPR in these rats during Tiron infusion (1g/kg/hour) averaged (13 ± 2; p<0.001); the attenuating effect of Tiron on the EPR was partly reversed when saline was reinfused into the superficial epigastric artery (21 ± 2; p<0.01 vs tiron). Tiron infusion had no effect on the EPR in rats with patent femoral arteries (n=9). Western blots showed that the triceps surae muscles taken from rats whose femoral arteries were ligated expressed more Nox2 and p67phox, which are components of NADPH oxidase, than did triceps surae muscles taken from rats whose femoral arteries were freely perfused. Tiron added to muscle homogenates reduced ROS production in vitro. Our results provide further evidence that ROS mediates the exaggeration of EPR in rats with simulated PAD. Support or Funding Information Funded by NIH R01 AR059397, NIH R01 HL130987, and NIH P01 HL096570