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. 2019 Mar 1;597(7):1919–1934. doi: 10.1113/JP277617

Figure 2. Effects of M‐Atr injections into the RTN on baseline breathing and ventilatory response to CO2 .

Figure 2

A, experimental design used to assess CO2 ventilatory responses by plesthysmography of awake or anaesthetized rats before and after bilateral RTN injections of saline or M‐Atr; open boxes during the last 2 min of each condition represent periods used for data analysis. B, histology section showing the location of the bilateral injection into the RTN. C–E, summary data (n = 6 rats) from awake rats showing that bilateral RTN injections of saline or M‐Atr (5 mm/50–75 nL) had negligible effects on V T (C), f R (D) or V E (E). F–H, summary data (n = 6 rats) from urethane (1.2 g kg–1) anaesthetized rats shows effects of bilateral RTN injections of saline or M‐Atr on V T (C), f R (D) and V E (E). M‐Atr decreased baseline breathing and the ventilatory response to CO2 in anaesthetized but not awake rats, thus demonstrating that cholinergic drive to the RTN helps maintain breathing during states of reduced consciousness. VII, facial motor nucleus; py, pyramidal tract. Scale bar = 1 mm. *Statistically different from saline (control) (two‐way RM ANOVA with Bonferroni's correction for multiple comparisons). [Color figure can be viewed at wileyonlinelibrary.com]