Individual Differences in Behavioural Despair Predict Brain GSK-3beta Expression in Mice: The Power of a Modified Swim Test
Brain activities of GSK-3beta in “high”- and “low-floaters” in the modified swim test. Mice were assigned to subgroups with “high-” () or “low-” floaters () using a mean of the groups as a criterion of a group formation. In comparison to intact controls, GSK-3beta mRNA (a) in the hippocampus and (b) in the prefrontal cortex was not significantly changed in either subgroup of mice on Day 1, Day 2, and Day 5 of swim test. (c) Hippocampal levels of GSK-3beta mRNA () did not correlate with total duration of floating on Day 5 of swim test. (d) The levels of GSK-3beta mRNA in prefrontal cortex () significantly correlated with the total duration of floating on Day 5 of a swim test. (e) In comparison to intact controls, hippocampal ratio of pS9 GSK-3beta /total GSK-3beta was significantly decreased both in “low” and “high” floating mice on Day 5, but not on Day 1 and Day 2. (f) In comparison to intact mice, the ratio of pS9 GSK-3beta /total GSK-3beta in prefrontal cortex was not significantly changed on Day 5 of swim test; size of groups as indicated above. , ANOVA and Tukey’s multiple comparisons test; see the text; LowF: subgroup of mice classified as “low-floaters”; HighF: subgroup of mice classified as “high-floaters.” D1: Day 1; D2: Day 2; D5: Day 5. Data are mean ± SEM.