Figure 2. Response to hypoxia in vivo.

A, recordings of spontaneous breathing activity in the two animal populations under normoxic conditions and at the end of hypoxia. Inspiration is upwards. B, analysis of ventilatory parameters shows that respiratory frequency was significantly increased in both populations (upper left panel), while tidal volume increased only in control animals (upper right panel). Minute ventilation and inspiratory inflow index were both increased only in the control population (lower left and right panels, respectively). **P < 0.01, ***P < 0.001, compared to baseline values; ##P < 0.01, ###P < 0.001, comparison between populations.