Je. Fewell et Fg. Smith, Perinatal nicotine exposure impairs ability of newborn rats to autoresuscitate from apnea during hypoxia, J APP PHYSL, 85(6), 1998, pp. 2066-2074
Failure to autoresuscitate by hypoxic gasping during prolonged sleep apnea
has been suggested to play a role in sudden infant death. Furthermore, mate
rnal smoking has been repeatedly shown to be a risk factor for sudden infan
t death. The present experiments were carried out on newborn rat pups to in
vestigate the influence of perinatal exposure to nicotine (the primary phar
macological and addictive agent in tobacco) on their time to last gasp duri
ng 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 w
ere exposed either to a single period of hypoxia (97% N-2-3% CO2) and their
time to last gasp was determined, or they were exposed repeatedly to hypox
ia 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 ev
idence that perinatal exposure to nicotine impairs the ability of newborn r
ats to autoresuscitate from primary apnea during repeated exposure to hypox
ia, such as may occur during episodes of prolonged sleep apnea.