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Chronic intermittent hypoxia abolishes respiratory LTF in rat pups and enhances apnea frequency
Author(s) -
Julien Cecile,
Niane Lalah,
Bairam Aida,
Joseph Vincent
Publication year - 2008
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.22.1_supplement.955.6
Subject(s) - medicine , apnea , intermittent hypoxia , hypoxia (environmental) , plethysmograph , anesthesia , ventilation (architecture) , respiratory system , apnea of prematurity , hypoxic ventilatory response , obstructive sleep apnea , pregnancy , biology , gestational age , chemistry , mechanical engineering , organic chemistry , oxygen , genetics , engineering
We tested the hypothesis that chronic intermittent hypoxia (IH) alters respiratory long‐term facilitation (LTF) induced by acute hypoxic episodes in newborn rats. Rat pups were exposed to normal room air (controls) or chronic IH (IH: O 2 levels cycled between 21% and 5% every 10 minutes for 1h; 1h normoxia, 24h/day) during postnatal days 1–10. To assess LTF, we measured minute ventilation (VE ‐ whole body plethysmography) in normoxia and during a recovery period of 2 hours following 10 acute hypoxic episodes. VE gradually increased (+23%) during recovery in controls, but decreased (−15%) in IH rats. In controls, frequency of apneas (≥2 missed breaths, measured before and at the end of recovery) slightly increased following acute hypoxic episodes (from 23±3 to 34±5 apneas/hour), while it dramatically increased in IH rats (from 26±4 to 61±6 apneas/hour). There was no gender‐specific effect. We conclude that in 10‐day old rats: i) LTF is present, ii) chronic IH abolishes LTF and iii) LTF appears to have a protective role against apneas. Neonatal apnea with IH may abolishe endogenous protective mechanisms, and contribute to increase apnea frequency in neonates. (FRSQ, CIHR, Sick kids foundation).