Prenatal cocaine: effect on hypoxic ventilatory responsiveness in neonatal rats.
The effects of prenatal (embryonic days 7-21) cocaine (30 mg/kg b.i.d., s.c.) exposure on postnatal respiratory and behavioral responsiveness to acute hypoxia were investigated in 5-day-old (P5) rat pups. Control and cocaine-exposed pups were subjected to 20 min of 0.21 FIO2 followed by 20 min of 0.08 FIO2. Although all pups demonstrated the characteristic biphasic response to hypoxia, cocaine-exposed pups exhibited a blunted, initial response in minute ventilation (p < 0.05) and inspiratory drive (p < 0.05) as compared with control pups who showed increases in these measures (p < 0.01 and p < 0.05, respectively). The consequence of this apparent blunted ventilatory response was reflected in blood gas data gathered after 20 min of 0.08 FIO2:PCO2 (p < 0.05) and base-excess (p < 0.05) were increased and HCO3- (p < 0.05) and SO2 (p < 0.01) were decreased relative to control pups. Cocaine-exposed pups also exhibited behavioral evidence of decreased struggling (p < 0.001) in response to the hypoxic challenge. These data in the rat confirm our previous findings of altered ventilatory responsiveness to inspired hypoxia in the rabbit and extend our observations of a decreased ability to successfully compensate and behaviorally arouse following prenatal cocaine-exposure, thus underscoring the potential vulnerability of infants so exposed.
Lipton
J W
JW
Department of Pediatrics, Rush Medical College, Rush University, Chicago, IL 60612, USA.
Davidson
T L
TL
Carvey
P M
PM
Weese-Mayer
D E
DE
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001522:Behavior, Animal / Q000187:drug effects; D003042:Cocaine / Q000008:administration & dosage* / Q000494:pharmacology; D005260:Female; D000860:Hypoxia / Q000503:physiopathology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration / Q000187:drug effects*
D003042:Cocaine