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. 2021 Aug 17;10:e67523. doi: 10.7554/eLife.67523

Figure 3. Network-level effects of MOR activation on spiking activity in the preBötC in vitro and in vivo.

(A) Representative ʃpreBötC activity from a horizontal slice during increasing concentrations of DAMGO. Orange asterisks indicate burst failures. (B) Averaged inter-burst intervals at baseline and in DAMGO demonstrating changes in IBI spiking. (C) Quantified ʃIBI spiking (RM one-way ANOVA [p<0.0001] with Bonferroni post hoc tests), burst frequency (RM one-way ANOVA [p<0.0001] with Bonferroni post hoc tests), frequency irregularity (RM mixed-effects analysis [p=0.01] with Dunnett’s post hoc tests), and amplitude irregularity (RM mixed-effects analysis [p=0.16] with Dunnett’s post hoc tests) from n=30 slices. (D) Averaged successful bursts compared to burst failures (top) and example intracellular recording during a failed burst (bottom). (E) Quantified fraction of burst failures during increasing concentrations of DAMGO (RM mixed-effects analysis [p<0.0001] with Bonferroni post hoc tests). (F) Schematic of in vivo experimental preparation with example simultaneous ʃXII and ʃpreBötC recordings. (G) Representative ʃXII and ʃpreBötC activity at baseline and following i.p. morphine. (H) Averaged ʃIBI spiking at baseline and following morphine. (I) Quantified ʃIBI spiking, breathing frequency, inter-burst interval, and inspiratory time (TI) (n=6; ratio paired t-tests). (J) Example changes in preBötC burst morphology in response to morphine administration in vivo. Data presented as means ± SE; significance of post hoc tests: *p<0.05, #p<0.01, †p<0.001, ‡p<0.0001 compared to baseline.

Figure 3—source data 1. Network effects of MOR activation.

Figure 3.

Figure 3—figure supplement 1. DAMGO dose responses.

Figure 3—figure supplement 1.

(A) DAMGO has similar effects on inspiratory burst frequency generated by wild-type (Oprm1WT / WT) and heterozygous (Oprm1Cre:GFP/WT) horizontal brainstems slices. Two-way RM ANOVA (p=0.47). (B) Naïve horizontal slices never exposed to DAMGO have a similar change in inspiratory burst frequency in 200 nM DAMGO compared to slices previously exposed to increases in (DAMGO) (two-tailed t-test at 200 nM DAMGO, p=0.63). Data shown and means ± SE.
Figure 3—figure supplement 1—source data 1. DAMGO dose responses.
Figure 3—figure supplement 2. Relationships between DAMGO-induced changes in inspiratory burst frequency and integrated inter-burst interval spiking in horizontal brainstem slice preparations.

Figure 3—figure supplement 2.

Linear regression analysis.
Figure 3—figure supplement 2—source data 1. Network effects of MOR activation.
Figure 3—figure supplement 3. Example whole-cell recording from an inspiratory neuron (top) and corresponding rhythmic multi-unit activity from the contralateral preBötC at baseline and in 300 nM DAMGO.

Figure 3—figure supplement 3.

Note that during failed population bursts in 300 nM DAMGO, the inspiratory neuron receives synaptic inputs that are not sufficient to recruit the neuron to spike.