Respiratory Plasticity Induced by Chronic Hyperoxia in Juvenile and Adult Rats.

Chronic hyperoxia during early postnatal development depresses breathing when neonatal rats are returned to room air and causes long-lasting attenuation of the hypoxic ventilatory response (HVR). In contrast, little is known about the control of breathing of juvenile or adult mammals after chronic exposure to moderate hyperoxia later in life. Therefore, Sprague-Dawley rats were exposed to 60% O for 7 days (juveniles) or for 4 and 14 days (adults) and ventilation was measured by whole-body plethysmography immediately after the exposure or following a longer period of recovery in room air.

Development of ventilatory chemoreflexes in Coturnix quail chicks.

Compared to mammals, little is known about the development of the respiratory control system in birds. In the present study, ventilation and metabolism were measured in Coturnix quail chicks exposed to room air, hypoxia (11 % O), and hypercapnia (4% CO) at 0-1, 3-4, and 6-7 days posthatching (dph). Mass-specific ventilation and metabolic rate tended to increase between 0-1 and 3-4 dph and then decrease again between 3-4 and 6-7 dph.