Intermittent hypoxia (IH), one of the hallmarks of obstructive sleep apnea, occurs more frequently during pregnancy. We hypothesized that IH may lead to persistent postnatal changes in respiratory responses to acute hypoxia and may also lead to adverse effects on spatial function learning as revealed by the Morris water maze. To examine this issue, time-pregnant Sprague-Dawley rats were exposed to IH and room air (IHRA; 21 and 10% O2 alternations every 90 seconds) or to normoxia (RARA) until delivery. Ventilatory and metabolic responses to a 20-minute acute hypoxic challenge (10% O2) were conducted at postnatal ages 5, 10, 15, and 30 days. In addition, spatial task learning was assessed in the water maze at 1 and 4 months of age. Normoxic ventilation was higher at all time points in IHRA rats than in RARA rats (p

Keywords: cognitive impairment; hypoxic ventilatory response; memory; obstructive sleep apnea; water maze

Environmental conditions during fetal and early postnatal life can induce profound alterations in the developmental characteristics of respiratory behaviors as well as other complex behaviors such as learned behaviors and spatial memory tasks (1-6). It has become clear that perturbations in gas exchange during early postnatal life can lead to marked modifications in the respiratory phenotype. For example, exposure to hyperoxic conditions during the first month of life will be associated with lifelong attenuations of peripheral chemoreceptor function (7). Similarly, in both rats and sheep, sustained postnatal hypoxemia has been shown to attenuate the hypoxic ventilatory response, an effect that may last until adulthood (8, 9). Thus, the brain regions underlying respiratory control mechanisms are susceptible to long-lasting forms of plasticity.  Medical Supply.