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Peripheral chemoreceptor contribution to ventilatory control during steady‐state exercise (873.2)
Author(s) -
Peinado Ana,
Johnson Blair,
Taylor Jennifer,
Joyner Michael
Publication year - 2014
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.28.1_supplement.873.2
Subject(s) - tidal volume , hypoxic ventilatory response , peripheral chemoreceptors , respiratory minute volume , carotid body , anesthesia , ventilation (architecture) , chemoreceptor , respiratory system , medicine , saline , respiratory rate , heart rate , control of respiration , cardiology , blood pressure , stimulation , mechanical engineering , receptor , engineering
We tested the hypothesis that the carotid body chemoreceptors (CB) contribute to ventilatory control during steady‐state exercise. Six men completed two randomized bouts of cycling exercise at 65% VO 2 max for up to 2 hours during an IV infusion of dopamine (D; 2 µg/kg/min) to acutely inactivate the CB, or a saline infusion (S). Expired gases were analyzed at baseline, resting‐infusion, and during exercise (25%, 50%, 75% and 100% of total exercise time). A hypoxic ventilatory response (HVR) test was performed after exercise during the infusion condition. Subjects were classified as responders (RS; n=3) if their HVR was lower during D vs. S (1.03 ± 0.6 vs. 2.14 ± 0.4 L/min/%SaO 2 ). In RS, partial pressure of end‐tidal CO 2 had a greater delta from baseline at 75% (2.9 ± 2.1 vs. 1.1 ± 1.9 mmHg) and 100% (0.9 ± 3.4 vs. ‐0.3 ±3.3 mmHg) during D than S, and the increase in oxygen uptake at 100% was greater during D vs. S (34.7 ± 2.6 vs. 33.0 ± 2.6 mL/min/kg). In RS, there were no differences in the changes from baseline for ventilation (VE), VE/VCO 2 , respiratory rate, tidal volume, and respiratory exchange ratio between conditions. In the non‐responders group, there were no differences between D and S in any variables. When the data was pooled, HVR accounted for 37% of the variance in VE at 100%. Despite evidence that CB chemosensitivity was blunted, the CB appear to play a minor role in controlling ventilation during steady state exercise. Grant Funding Source : NIH R01DK090541