Invited Editorial Assisting Mother Nature in postnatal chemoreceptor maturation

insensitive to hypoxia and begin maturing to normal hypoxia sensitivity over the first postnatal days to weeks. The signal that initiates this maturation process is unresolved but appears to be related to the increase in the partial pressure of arterial oxygen (PaO2), which takes place at the time of birth. Birthing into a low-oxygen atmosphere and clinical syndromes such as congenital heart disease that limit the postnatal increase in PaO2 result in a prolonged, impaired chemoreceptor response to hypoxia when measured at ages that should show a potent sensitivity to hypoxia (3). This impairment is often maintained despite a correction to normal levels of oxygen (6). Similarly, but likely through a different mechanism, postnatal exposure to high levels of oxygen results in impaired chemoreceptor func-tion (2), which is maintained through adulthood, despite a return to normal oxygen levels (1)