A, B, representative traces of minute ventilation (VE), tidal volume (VT) and respiratory frequency (fR) from anesthetized DBA/1 mice treated with vehicle (saline, 10 ml/kg, IP) or atomoxetine (15 mg/kg, IP), respectively, in room air or room air plus 7% CO2. Data were normalized to the averaged baseline value of VE, VT or fR. Averaged baseline values of VE, VT and fR were 13.3 ± 1.4 ml/20 g/min, 0.15 ± 0.02 ml/20 g/min and 96.3 ± 11.2 breaths/min, respectively. Traces between the two dotted lines denote the effect in response to room air plus 7% CO2. C, comparison of the vehicle and atomoxetine effects on the normalized VE, VT or fR in room air and in room air plus 7% CO2 in anesthetized DBA/1 mice at the period of 120–130 min (mean value of 10-min recordings) after IP injection, at which atomoxetine at this dosage is known to reduce S-IRA (Zhang et al., 2017).
* p < 0.05; ** p < 0.01: Significantly different from the vehicle control.