Tidal volume (VT), frequency, minute ventilation () and mean inspiratory flow (VT/TI) during baseline and HX + HC in wild-type (WT; black bars) and mutant (MT; white bars) rats treated with apocynin (Apo) + MSX-3 + methy versus sham treated rats. In all groups, HX + HC values were significantly larger than baseline values. Apo + MSX-3 + methy significantly increased VT, and VT/TI during HX + HC in MT rats versus sham treated MT rats. Values are means ± 1 SEM and * = from sham MT, + = from sham WT, where all p < 0.05.