Figure 4.

Perturbations of respiratory activity by pharmacologically disrupting GABA_Aergic and glycinergic inhibition in the pre-BötC of anesthetized adult rat in vivo. A, Simultaneous bilateral microinjections of gabazine and strychnine (both 250 µm delivered by slow microinjections of 110 nl during the time interval indicated by the brown bar at the top and blue rectangle) caused an increase of respiratory frequency and a reduction in the integrated phrenic nerve activity amplitude (∫PN; black trace, top). The increase of respiratory frequency (f_R; green trace, bottom) was mainly due to reductions of expiratory phase duration (T_E, blue trace) accompanied by only a small increase of inspiratory phase duration (T_I, red trace). B–E, Group mean time series showing developing changes of normalized T_I (B, red curve), T_E (C, blue curve), f_R (D, green curve), and ∫PN amp (E, magenta curve) computed over the time window shown from the start (time = 0) of microinjection. Data were computed from ∫PN for this representative experimental group (n = 6). Solid colored curves are group mean time and mean normalized parameter values; gray shaded bands are ±1 SEM for the mean parameter values. Endpoints shown are mean time and normalized parameter values ±1 SEM for both at the maximal perturbation for the injection periods used.