Figure 5.

Inhibitory phosphorylation on GSK-3 is increased in Trpm2^−/− mice. A, Representative Western blots of total and phosphorylated GSK-3α and GSK-3β obtained from the frontal cortices of saline (Sham) or amphetamine-treated (AMP) WT and Trpm2^−/− mice. Protein samples were acquired 30 min after the injection of saline or AMP. B, Quantitative comparisons of the levels of phosphorylated GSK-3α and GSK-3β obtained from frontal cortices of saline-treated WT and Trpm2^−/− mice. The levels of phosphorylated GSK-3α and GSK-3β were normalized to the levels of total GSK-3α and GSK-3β, respectively. ***p < 0.001, Student's t test. C, Summary of the effects of AMP on GSK-3α and GSK-3β phosphorylations in the frontal cortices of WT and Trpm2^−/− mice. *p < 0.05, **p < 0.01, Student's t test. D, Representative Western blots of total and phosphorylated GSK-3α and GSK-3β from the frontal cortices of saline (sham) or Li⁺-treated WT and Trpm2^−/− mice. Western blots were conducted with protein samples acquired from the frontal cortices of WT and Trpm2^−/− mice administered with saline or Li⁺ (150 mg/kg, i.p.) daily for 5 d. E, Summary of the effects of Li⁺ on GSK-3α and GSK-3β phosphorylations in the frontal cortices of WT and Trpm2^−/− mice. Note that the administration of Li⁺ significantly augmented the expression levels of phosphorylated GSK-3α and GSK-3β compared with those treated with saline; however, the Li⁺ effect was not observed in Trpm2^−/− mice. F, Western blots of β-catenin from frontal cortices of saline-treated WT and Trpm2^−/− mice. The level of β-catenin was normalized to the level of α-tubulin (bottom). **p < 0.01, Student's t test.