Figure 3. Nurr1^−/− mice experience frequent apnoeas and heterozygote Nurr1 mice have altered hypoxic response.

The number (A) and duration (B) of apnoeas in Nurr1^+/− and Nurr1^+/+ pups decreased during hypoxia (5% O₂) and then increased during posthypoxic recovery in normoxia. Note that during posthypoxia apnoeas were more numerous and their duration longer in Nurr1^+/− compared to Nurr1^+/+ mice (P <0.0001). Nurr1^−/− did not show any variations of the number or duration of apnoeas during or after hypoxia. During air and hypoxia the Nurr1^−/− pups displayed more apnoeas with longer total duration than the other genotype groups (P <0.0001), and compared to Nurr1^+/+ (P <0.05), but not compared with Nurr^+/−, after hypoxia. *P<0.05; **P<0.01; ***P<0.001. Values are means ±s.e.m.