Regulation of protein phosphorylation by glutamate and a D1 receptor agonist in brain slices from nNOS KO mice. Neostriatal slices from wild-type (open circles) and nNOS KO (closed circles) mice were treated with glutamate (5 mM) (A-C) and a dopamine D1 receptor agonist, SKF81297 (1 μM; D-I) for the indicated times. Changes in the phosphorylation of DARPP-32 at Thr34 (B, E) and Thr75 (C, F), GluR1 at Ser845 (G), ERK2 (H), and spinophilin at Ser94 (I) were determined by Western blotting using phosphorylation-state specific antibodies. Typical immunoblots detected with phosphorylation-state specific and total DARPP-32 antibodies are shown in (A, D). Data represent means ± SEM for 3–9 experiments. *p < 0.05, **p < 0.01 compared with untreated slices (time 0) from wild-type mice; †p < 0.05, ††p < 0.01 compared with untreated slices (time 0) from nNOS KO mice; one-way ANOVA followed by Newman-Keuls test. §p < 0.05 compared with values of wild-type mice; two-way ANOVA followed by Bonferroni test.