Fewell J E, Smith F G
Department of Physiology and Biophysics, Health Sciences Centre, The University of Calgary, Calgary, Alberta, Canada T2N 4N1.
J Appl Physiol (1985). 1998 Dec;85(6):2066-74. doi: 10.1152/jappl.1998.85.6.2066.
Failure to autoresuscitate by hypoxic gasping during prolonged sleep apnea has been suggested to play a role in sudden infant death. Furthermore, maternal smoking has been repeatedly shown to be a risk factor for sudden infant death. The present experiments were carried out on newborn rat pups to investigate the influence of perinatal exposure to nicotine (the primary pharmacological and addictive agent in tobacco) on their time to last gasp during a single hypoxic exposure and on their ability to autoresuscitate during repeated exposure to hypoxia. Pregnant rats received either nicotine (6 mg. kg-1. 24 h-1) or vehicle continuously from day 6 of gestation to days 5 or 6 postpartum via an osmotic minipump. On days 5 or 6 postpartum, pups were exposed either to a single period of hypoxia (97% N2-3% CO2) and their time to last gasp was determined, or they were exposed repeatedly to hypoxia and their ability to autoresuscitate from primary apnea was determined. Perinatal exposure to nicotine did not alter the time to last gasp, but it did impair the ability of pups to autoresuscitate from primary apnea. After vehicle, the pups were able to autoresuscitate from 18 +/- 1 (SD) periods of hypoxia, whereas, after nicotine, the pups were able to autoresuscitate from only 12 +/- 2 periods (P < 0.001) of hypoxia. Thus our data provide evidence that perinatal exposure to nicotine impairs the ability of newborn rats to autoresuscitate from primary apnea during repeated exposure to hypoxia, such as may occur during episodes of prolonged sleep apnea.
长时间睡眠呼吸暂停期间因低氧喘息而无法自动复苏被认为在婴儿猝死中起作用。此外，母亲吸烟已反复被证明是婴儿猝死的一个危险因素。本实验在新生大鼠幼崽上进行，以研究围产期暴露于尼古丁（烟草中的主要药理和成瘾剂）对其在单次低氧暴露期间至最后喘息时间以及在反复暴露于低氧期间自动复苏能力的影响。怀孕大鼠从妊娠第6天至产后第5天或第6天通过渗透微型泵持续接受尼古丁（6毫克·千克⁻¹·24小时⁻¹）或赋形剂。在产后第5天或第6天，幼崽要么暴露于单一时期的低氧（97%氮气 - 3%二氧化碳）并确定其至最后喘息的时间，要么反复暴露于低氧并确定其从原发性呼吸暂停中自动复苏的能力。围产期暴露于尼古丁并未改变至最后喘息的时间，但确实损害了幼崽从原发性呼吸暂停中自动复苏的能力。给予赋形剂后，幼崽能够从18±1（标准差）次低氧时期中自动复苏，而给予尼古丁后，幼崽仅能从12±2次（P<0.001）低氧时期中自动复苏。因此，我们的数据提供了证据，表明围产期暴露于尼古丁会损害新生大鼠在反复暴露于低氧（如在长时间睡眠呼吸暂停发作期间可能发生的情况）期间从原发性呼吸暂停中自动复苏的能力。
