Figure 2.

In vivo modulation of breathing by the μ-opioid agonist DAMGO at the preBötC across sleep–wake states. A, Recordings of a whole experimental protocol with traces showing the prevailing sleep–wake states, electroencephalogram (EEG) activity, integrated neck muscle activity, mean respiratory rate (derived from successive 10 s time-bins), instantaneous (breath-by-breath) rate, and integrated diaphragm (Dia) muscle activity. The top line represents the time course for the continuous perfusion of the different drugs into the preBötC, with the dashed lines showing the 30 min periods used to calculate the mean data used in Figure 3. Note the persistent suppression of respiratory rate during perfusion of DAMGO, which is especially apparent during non-REM sleep, and the subsequent reversal of this rate depression by naloxone. B, C, DAMGO (20 μm) at the preBötC caused respiratory slowing in wakefulness (B) and non-REM sleep (C), with this effect reversed by naloxone.