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. Author manuscript; available in PMC: 2009 Dec 10.
Published in final edited form as: Respir Physiol Neurobiol. 2008 Dec 10;164(1-2):263–271. doi: 10.1016/j.resp.2008.07.008

Figure 4.

Figure 4

Tert-Butyl H2O2, a stable form of hydrogen peroxide, applied to tissue homogenates of the ventral cervical spinal cord containing the phrenic motor nucleus reduces the activity of protein phosphatase 2A (PP2A, Wilkerson and Mitchell, unpublished data). These data confirm that at least one form of ROS inhibits PP2A in spinal regions involved in pLTF. PP2A is a serine/threonine protein phosphatase thought to constrain phrenic LTF (Wilkerson et al., 2007). Tissues were collected, processed and analyzed for phosphatase activity as described in Wilkerson et al. 2008. Briefly, cytosolic fraction samples (n=8) were stripped of free phosphates, then treated in vitro with 1 μL of 70% TBHP. PP2A activity was then measured as the picomoles of phosphate generated from a provided phosphopeptide substrate per minute and normalized to total protein within the sample; data are presented as the mean ± SEM of the change in PP2A activity as a percentage of PP2A activity relative to untreated samples from the same animal. *denotes significant difference from basal (i.e. untreated) levels of PP2A activity (one-sample t-test, p<0.05).