Arousal response to hypoxia in newborns: Insights from animal models.

In newborns, the inability to initiate an arousal response to hypoxia is associated with apnea of prematurity, sudden infant death syndrome, and rare genetic disorders of respiratory control. Despite intensive research, the mechanisms of this response are poorly understood. This paper provides an overview of studies investigating the arousal response to hypoxia, with special emphasis on newborn mouse models. Mutant mouse models can provide valuable information regarding the pathogenesis of genetically determined disorders affecting arousal response to hypoxia, although data remain sparse. In mice, the arousal response to hypoxia emerges immediately after birth, when the ventilatory response to hypoxia is still immature. Habituation of the arousal response occurs after repeated hypoxic episodes. Newborn mice can learn to associate novel odors to hypoxia and respond to those odors by producing alerting responses, suggesting that the arousal response to hypoxia may be shaped by learning processes.