Effect of NO-711 on residual apneas in Mecp2−/+ mice studied in situ. (A) HN, AbN, and PN traces before (control) and after adding NO-711 (5.2 μM) to the perfusate. (B.1–B.3) Effect of the GABA reuptake blocker on (B.1) the incidence of apnea (*P = 0.009, n = 5, paired t test), (B.2) the HN burst envelope in residual PN apneas (*P = 0.005, n = 5), and (B.3) the incidence of apneas that contained tonic AbN activity (*P = 0.04, n = 4).