Premium
Persistent augmentation of the blood pressure and heart rate responses to dynamic exercise in rats with chronic bilateral femoral artery occlusion
Author(s) -
Kuczmarski James M.,
Unrath Kellee,
Thomas Gail D.
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.761.5
Subject(s) - medicine , heart rate , ligation , blood pressure , cardiology , perfusion , femoral artery , hemodynamics , treadmill , physical exercise , mean arterial pressure , blood flow
The blood pressure (BP) response to treadmill walking or low‐intensity leg exercise is exaggerated in patients with atherosclerotic peripheral artery disease (PAD), but the contribution of muscle hypoperfusion to the heightened pressor response independent of other disease mechanisms is unclear. In healthy humans and animals, the pressor response to exercise is augmented when blood flow is acutely restricted to the active muscles. Whether BP is similarly exacerbated by chronic hypoperfusion of exercising muscle is uncertain, because BP during exercise is reported to be both increased and unchanged in cross‐sectional studies of rats with occluded versus freely perfused hindlimbs. To address this question, we performed a longitudinal study of the pressor response to exercise before and after bilateral femoral artery ligation in Sprague Dawley rats (n = 8; 5M, 3F). BP and heart rate (HR) were measured using radiotelemetry before, during, and after treadmill exercise (15 m/min; 5° incline) at repeated intervals pre‐and post‐ligation. Before ligation, exercise evoked reproducible increases in mean BP (115 ± 1 vs 123 ± 2 mmHg, P<0.05) and HR (402 ± 13 vs 496 ± 11 bpm, P<0.05), both of which returned to pre‐exercise levels within 10 min of recovery (108 ± 2 mmHg and 405 ± 12 bpm, P>0.05 vs pre‐exercise). Beginning as early as day 3 post‐ligation, the exercise‐induced increases in mean BP (+15 ± 2 mmHg) and HR (+150 ± 9 bpm) were augmented compared to the pre‐ligation responses (BP, +8 ± 2 mmHg; HR, +94 ± 11 bpm; both P<0.05 vs day 3). BP responses remained enhanced by 1.6–2.2 fold and HR by 1.2–1.4 fold from day 6 until the final measurement at day 28 post‐ligation (BP, +16 ± 2 mmHg; HR, +138 ± 11 bpm; p<0.05 vs pre‐ligation). These findings indicate that non‐atherosclerotic femoral artery occlusion elicits exaggerated, sustained BP and HR responses to dynamic exercise in rats that resemble those of PAD patients, suggesting that functional muscle ischemia is an independent factor underlying abnormal cardiovascular responses to exercise. Long‐term telemetric recording of blood pressure coupled with treadmill exercise offers a sensitive method to evaluate cardiovascular mechanisms and potential therapeutic interventions in rodent models of demand ischemia.