Fig. 5. Summary of effects of hypoxia on (A) lung burst episode frequency and (B) number of lung bursts per episode in pre-metamorphic tadpole (white bars), post-metamorphic tadpole (black bars) and adult (hatched bars) brainstems. Data for post-metamorphic tadpole and adult preparations were obtained during the initial 5–15 min exposure to hypoxia, prior to the respiratory cessation that occurred in these preparations (see text). ^*P<0.05 compared with control values.