Figure 2. Inhibition is not essential for normal rhythmogenesis in adult rat.

Block of postsynaptic inhibition within preBötC and BötC in vagus intact adult rat slows breathing frequency to that of vagotomized rat and completely blocks the Breuer–Hering inflation reflex. Top, lung inflation resulting from increased tracheal pressure (TP; 10 cmH₂O) causes apnoea as reflected in loss of activity in diaphragmatic EMG (∫EMG_DIA). Bottom, after microinjection of bicuculline and strychnine, GABA_A and glycine antagonists, rhythm persists but lung inflation no longer has an effect on rhythm. Scale bars, 100 arbitrary units, 10 s. Adapted from Janczewski et al. (2013).