Prenatal nicotine exposure alters the response of the mouse in vitro respiratory rhythm to hypoxia.

Prenatal nicotine exposure is associated with deficiencies in the ability to respond to life threatening stressors such as hypoxia. Although many of these deficiencies appear to originate from defects in the brainstem respiratory network, the specific effects of prenatal nicotine exposure on the brainstem respiratory network are not well understood. We have tested the effects of prenatal nicotine exposure on the respiratory rhythm using an in vitro mouse brainstem slice preparation containing the pre-Bötzinger Complex, a region of the ventral respiratory group that is the postulated site of inspiratory rhythm generation. We found that nicotine exposure during pre- and early postnatal development led to a lower frequency of baseline fictive respiratory discharges from rhythmic slices and a reduction in the ability of the slice to maintain a respiratory rhythm during exposure to severe hypoxia compared to controls. These impairments of the central respiratory rhythm could potentially affect the ability to survive a period of exposure to severe hypoxia in vivo.