Figure 5.

A, B, Regulation of STEP and ERK2 signaling after intrastriatal QUIN injection. pSTEP₆₁ (A) pSTEP₄₆ (B), and pERK2 (C) levels were analyzed by Western blot of protein extracts obtained from the striatum of 12-week-old WT and R6/1 mice, 1 and 4 h after an intrastriatal injection of vehicle or QUIN (10 nmol). Representative immunoblots show protein levels of pSTEP₆₁, STEP₆₁, and α-tubulin (A), pSTEP₄₆, STEP₄₆, and α-tubulin (B), and pERK2, ERK2, and α-tubulin (C) in WT and R6/1 striatum, 1 and 4 h after QUIN injection. Values (obtained by densitometric analysis of Western blot data) are expressed as percentage of the contralateral vehicle-injected WT striatum (pSTEP₆₁/STEP₆₁ ratio, pSTEP₄₆/STEP₄₆ ratio, or pERK2/ERK2 ratio, after normalization with α-tubulin), and data shown are the mean ± SEM (n = 7–9). Data were analyzed by two-way ANOVA, followed by Bonferroni's post hoc test. *p < 0.05, **p < 0.01, and ***p < 0.001 compared with vehicle-injected contralateral WT striatum. WT, Vehicle-injected WT striatum; WT + QUIN, QUIN-injected WT striatum; R6/1, vehicle-injected R6/1 striatum; R6/1 + QUIN, QUIN-injected R6/1 striatum.