Effects of suramin (A) or A-317491 (B) on minute-by-minute changes of ventilatory response to hypoxia in P4, P7, and P21 rats. The suramin dose was 40 mg/kg (IP), and the A-317491 dose was 150 mg/kg (IP). Figure 1 presents representative tracings from this experimental group. A: n values are as follows for vehicle and suramin, respectively: 10 and 10 (P4), 10 and 12 (P7), and 14 and 11 (P21). B: n values are as follows for vehicle and A-317491, respectively: 10 and 5 (P4), 6 and 6 (P7), and 10 and 6 (P21). The bar with the asterisk indicates significant difference between vehicle (○) and suramin (●; A) or A-317491 (●; B) at each point.