Schuen J N, Bamford O S, Carroll J L
DeVos Children's Hospital at Butterworth, Grand Rapids, MI 49503, USA.
Respir Physiol. 1997 Sep;109(3):231-9. doi: 10.1016/s0034-5687(97)00052-2.
Maternal smoking increases the risk of the sudden infant death syndrome (SIDS) 2-4-fold. The mechanism is unknown but may be related to hypoxia responses. Recovery from hypoxic apnea by young mammals depends on gasping and bradycardia. We asked whether prenatal nicotine exposure, reported to reduce hypoxic survival in 2 day old rat pups, acted by impairing gasping or bradycardia. Pregnant rats were infused throughout gestation and 1 week postnatally with nicotine tartrate (NIC) 12 mg/kg per day or saline (CON). Maternal plasma nicotine was 134.4 +/- 42 ng/ml, significantly reducing pup body weight. Pups at 3-28 days were exposed to anoxia (97% N2/3% CO2) until gasping ceased, while breathing and heart rate were recorded. NIC and CON groups were not significantly different at any age, in baseline heart rate, respiratory rate, the time course for bradycardia, time to gasp onset, duration of gasping, or number of gasps, although most of these variables declined significantly with age. We conclude that responses to anoxia are not affected by prenatal high-dose nicotine.
母亲吸烟会使婴儿猝死综合征（SIDS）的风险增加2至4倍。其机制尚不清楚，但可能与缺氧反应有关。幼年哺乳动物从缺氧性呼吸暂停中恢复取决于喘息和心动过缓。我们研究了产前尼古丁暴露是否通过损害喘息或心动过缓起作用，据报道产前尼古丁暴露会降低2日龄大鼠幼崽的缺氧存活率。在整个妊娠期及产后1周，给怀孕大鼠每天注射12mg/kg酒石酸尼古丁（NIC）或生理盐水（CON）。母体血浆尼古丁浓度为134.4±42ng/ml，显著降低了幼崽体重。在3至28日龄时，将幼崽置于缺氧环境（97%N2/3%CO2）中直至喘息停止，同时记录呼吸和心率。在任何年龄，NIC组和CON组在基线心率、呼吸频率、心动过缓的时间进程、喘息开始时间、喘息持续时间或喘息次数方面均无显著差异，尽管这些变量大多随年龄显著下降。我们得出结论，产前高剂量尼古丁不会影响对缺氧的反应。
