Fig. 2.

Effects of PE injections into the XII nucleus in rats exposed to chronic intermittent hypoxia (CIH) and sham-treated rats. A: integrated XII nerve activity (∫XIIa) prior to and following PE injection in a sham-treated rat. B: expanded segments of raw and integrated XIIa corresponding to the shaded areas in A. C: PE injection site for the experiment illustrated in A. Pontamine sky blue dye was injected with PE and is seen in the right XII nucleus (XIIn) in a neutral red-stained coronal section. Nucleus of the solitary tract (NTS) is shown as an orientation landmark. D and E: mean effects of PE injections into the XII nucleus on XIIa area under the curve (AUC) and central respiratory rate in CIH- and sham-treated rats. Values (means ± SE) for each measurement period are plotted at the time corresponding to the end of that period. Excitatory effect of PE on XIIa was of similar magnitude in both groups, and injections did not affect central respiratory rate. XIIa was significantly increased compared with the baseline level up to min 3 following PE injection when both treatment groups were combined (Friedman's ANOVA, Tukey-corrected multiple comparisons, P < 0.05).