Figure 5. A loss of brainstem 5-HT neurones has no effect on the ventilatory response to CO₂ at P5 or P15.

A, ventilation of WT and Pet-1^−/− (KO) animals at P5 and P15, during room air and after 2 min of 5% CO₂ balanced with air (CO₂–air). B, of WT and Pet-1^−/− animals during room air and after 2 min of 5% CO₂ balanced with O₂ (CO₂–O₂). C, increase in (% change) after 2 min of either CO₂–air or CO₂–O₂ in each genotype at P5 and P15. All data are means ± SE.