Ventilatory and chemoreceptor responses to hypercapnia in neonatal rats chronically exposed to moderate hyperoxia.

Rats reared in hyperoxia hypoventilate in normoxia and exhibit progressive blunting of the hypoxic ventilatory response, changes which are at least partially attributed to abnormal carotid body development. Since the carotid body also responds to changes in arterial CO/pH, we tested the hypothesis that developmental hyperoxia would attenuate the hypercapnic ventilatory response (HCVR) of neonatal rats by blunting peripheral and/or central chemoreceptor responses to hypercapnic challenges. Rats were reared in 21% O (Control) or 60% O (Hyperoxia) until studied at 4, 6-7, or 13-14days of age.