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Exercise performance in moderate hypoxia in rats with impaired carotid bodies
Author(s) -
Meyers Kristen A,
Young Kristen M,
Bavis Ryan W
Publication year - 2009
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.23.1_supplement.616.4
Subject(s) - hyperoxia , hypoxia (environmental) , carotid body , treadmill , medicine , endocrinology , hypoxic ventilatory response , cardiology , oxygen , respiratory system , chemistry , lung , carotid arteries , organic chemistry
Previous studies have shown a positive correlation between the magnitude of the resting hypoxic ventilatory response (HVR) and exercise performance at high altitude in humans. We employed a rodent model to experimentally test this relationship. Rats exposed to chronic hyperoxia during postnatal development exhibit smaller carotid bodies and reduced HVR as adults. Therefore, rats were exposed to 60% O 2 for the first 2 postnatal weeks. At 2‐3 months of age, these rats were run on a treadmill at various work rates in both room air and moderate hypoxia (12% O 2 ) to assess endurance (time to exhaustion at 20 m/min, 5° incline) and maximal rate of O 2 consumption (VO 2 ,max). Running times and VO 2 ,max were reduced by hypoxia in both control and hyperoxia‐treated rats (P<0.001). In hypoxia, hyperoxia‐treated rats exhibited somewhat shorter times to exhaustion than controls (21±2 (SEM) vs. 29±2 min; P<0.01). In contrast, VO 2 ,max during moderate hypoxia did not differ between treatment groups. Although HVR was not measured in this study, histology confirmed a significant reduction in carotid body volume in hyperoxia‐treated rats (P<0.01). We conclude that HVR and/or carotid body size may have modest effects on hypoxic exercise performance in rats. Supported by NIH grant P20 RR‐016463 (Maine INBRE).