Figure 8.

NK-1 receptor activation in situ contributes to maintenance of inspiratory burst amplitude. A, Blocking endogenous substance P activity through antagonism of NK-1 receptors with SR 140333 did not significantly alter inspiratory burst frequencies in the XII nerve and pre-BötC (data not shown) as indicated by the steady-state responses to SR shown. B, Attenuation of integrated inspiratory burst amplitudes in the pre-BötC and XII nerve by SR, indicating disproportionate reductions in pre-BötC population activity and XII motor output, where the steeper attenuation of XII activity suggests additional NK-1 modulation of XII inspiratory burst generation downstream from the pre-BötC. Data points represent mean values ± SEM.