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. Author manuscript; available in PMC: 2018 Aug 1.
Published in final edited form as: Neurobiol Aging. 2017 Apr 26;56:100–107. doi: 10.1016/j.neurobiolaging.2017.04.010

Figure 5. Lateralized, age-dependent changes in CeA nociceptive signaling occur after peripheral formalin injection.

Figure 5

Peripheral injury is known to increase ERK activation partially through the signaling cascade downstream of mGluR5. Western analysis was used to evaluate these proteins 180 after formalin testing. (a) Representative blot of pERK and total ERK in the left and right CeA of young (2 mo), middle age (12 mo) and old (22 mo) mice. (b) Quantification of ERK1 activation showed significant age-dependent effects and that old animals express more pERK1 in the right CeA compared to the left CeA (Two-way ANOVA, effect of age p=0.0229, effect of side of brain p=0.0219; Bonferroni post-test, 22 mo left vs. right *p<0.05; n=6–9). (c) No age-dependent changes were noted in pERK2 expression following formalin injection (Two-way ANOVA, no main effect of age p=0.4476; n=6–9). (d) Representative blot of mGluR5 and loading control Beta-actin in the left and right CeA of young (2 mo), middle age (12 mo) and old (22 mo) mice. (e) Quantification revealed that following formalin injection, CeA mGluR5 expression is increased to approximately the same level across all age groups (Two-way ANOVA, effect of age p=0.7882; n=6). Notably, most of the mGluR5 expression changes appeared to occur in the right CeA; both young and old mice exhibit significantly more mGluR5 in the right CeA than the left CeA (effect of side of brain p<0.0001; Bonferroni post-test, 2 mo right vs. left ** p<0.01, 22 mo right vs. left *p<0.05).