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“Full term” prenatal nicotinic exposure (fPNE) produces a depressed hypoxic ventilatory response (dHVR) in postnatal rats
Author(s) -
Xu Fadi,
Zhuang Jianguo
Publication year - 2012
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.26.1_supplement.894.19
Subject(s) - hypoxia (environmental) , cardiorespiratory fitness , sudden infant death syndrome , medicine , hypoxemia , bradycardia , plethysmograph , gestation , lactation , pregnancy , physiology , endocrinology , anesthesia , heart rate , biology , blood pressure , chemistry , oxygen , pediatrics , organic chemistry , genetics
Maternal smoking is the key risk factor and hypoxemia is an acute precursor for SIDS. An existing SIDS rat pup model induced by a traditional PNE (tPNE) covering the last 2/3 of the gestation period shows an excessive mortality (15%) during 60 min severe hypoxia. We tested if fPNE consisting of the periods immediately before pregnancy and during pregnancy and lactation would depress HVR, leading to a higher mortality than tPNE. After detecting the metabolism and collecting blood sample, awake P11‐14 rats pretreated with vehicle (Ctrl), tPNE, and fPNE were individually placed in a plethysmograph and exposed to 5% O2 for 60 min with the rectal temperature at ~34.0°C. We found that fPNE induced a dHVR 38 ± 4% (P < 0.01) lower than tPNE and Ctrl pups without effects on baseline VE, HR, metabolism, body weight and temperature, blood gases, and pH. Dramatic bradycardia associated with apneas and gasps occurred 35 ± 3.3 min after hypoxia, which led to a lethal VE arrest 42 ± 2.7 min after hypoxia with heart beat persisting for additional several min in 10/16 fPNE pups (63% mortality). Neither the dHVR nor the cardiorespiratory failure (death) was observed in all Ctrls and 6/8 tPNE pups during this period. Two remaining tPNE pups died (25% mortality) ~54 min after hypoxia following a less dHVR. Our results suggest that fPNE with a higher mortality and worse dHVR is a more suitable SIDS model than tPNE (Supported by HL 107462 and ALA RG‐191095‐N).