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Figure 1: Substance P- (SP-) dependent modulation of the embryonic respiratory rhythm. (a) Schematic of the embryonic transverse brainstem slice isolating the preBötC network with the position of an extracellular recording electrode indicated. Integrated network activity (Int preBötC) recorded in control conditions (top), in the presence of 0.5 μM SP (middle) and after 30 minutes’ wash-out (bottom). (b) Pooled data showing mean (± SEM) inspiratory burst frequency obtained from 20 embryonic slices in control conditions (CTL, white bar), after 15 min exposure to 0.5 μM SP (black bar) and after wash-out (gray bar). SP significantly increased the frequency of the spontaneous preBötC network rhythm. This effect was also partially reversible. The asterisk indicates significant difference at . (c) Immunodetection of NK1R receptors (red staining) in the preBötC area located ventral to the nucleus ambiguus (na) that was positive to both NK1R (red) and ChaT (green). D: dorsal, M: medial, and na: nucleus ambiguus.