Co-immunoprecipitation using agarose beads reveals that CIH increase the level of nitrated MnSOD in the CBs (A) and adrenal medulla (C), and that this nitration is prevented with administration of ascorbic acid concomitant with CIH (CIH-AA), n=12 rats per lane. MnSOD enzymatic activity was measured in CB homogenates in the three groups using a colorimetry kit. ***p<0.001 versus sham and CIH-AA, *p<0.05 versus sham and CIH-AA. Bonferroni after one-way ANOVA. For CBs n=11–12 rats per group; for adrenal medullas n=7–8 rats per group. Abbreviations: CIH, chronic intermittent hypoxia; CB, carotid body.