Altered breathing pattern after prenatal nicotine exposure in the young lamb.
Maternal smoking during pregnancy is a risk factor for sudden fetal and infant death as well as obstructive airway disease in childhood. Fetal nicotine exposure affects organ development. The aim of the present study was to investigate effects of fetal nicotine exposure on lung function in young lambs. Nine unanesthetized, awake, prenatally nicotine-exposed lambs (N) (approximate maternal dose: 0.5 mg/kg) and 12 nonexposed control lambs (C) were studied repeatedly for 5 weeks after birth using a pneumotachograph and a computerized method for breath-by-breath determinations. N and C lambs had similar minute ventilation but a markedly different breathing pattern. At both 5 and 21 days, average age, N lambs had significantly lower tidal volumes and higher respiratory rates than C lambs. Inspiratory drive (P(0.1)) and effective impedance were significantly higher in N lambs compared with C lambs only at 5 days. Prenatal nicotine exposure appears to have long-term effects on the postnatal breathing pattern, suggesting altered lung function, e.g., increased airway resistance, decreased lung compliance, or both. The increased inspiratory drive is most likely secondary to increased impedance of the respiratory system. These changes are most marked close to birth but persist during the initial postnatal period.
Hafström
Ola
O
Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2585, USA.
Milerad
Joseph
J
Sundell
Håkan W
HW
D000818:Animals; D000831:Animals, Newborn; D004305:Dose-Response Relationship, Drug; D005260:Female; D008168:Lung / Q000196:embryology; D009538:Nicotine / Q000009:adverse effects*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012044:Regression Analysis; D012119:Respiration / Q000187:drug effects*; D015656:Respiratory Mechanics / Q000187:drug effects; D012756:Sheep
D009538:Nicotine