Individual Differences in Behavioural Despair Predict Brain GSK-3beta Expression in Mice: The Power of a Modified Swim Test
Brain expression of GSK-3beta in the modified swim test and the role of context, swimming, and timing of testing. (a) In comparison to intact controls (), hippocampal GSK-3beta mRNA levels were significantly elevated only on Day 5 (), but not on Day 1 () or Day 2 (). (b) In the prefrontal cortex, the GSK-3beta mRNA levels were not changed on Day 1, Day 2, or Day 5; group sizes as indicated above. As compared with intact mice (), there was no change in GSK-3beta mRNA in mice sacrificed 24 h after swim session on Day 5 in the hippocampus (c), nor in the prefrontal cortex (d); in each experimental group. (e) In comparison to intact controls (), hippocampal GSK-3beta mRNA levels were not significantly altered in mice tested and sacrificed on Day 3 () nor in mice sacrificed on Day 5 without any behavioural manipulations () or exposed to a context at testing on Day 5 (). (f) In comparison to intact controls, GSK-3beta mRNA levels were not changed in the prefrontal cortex of mice exposed to testing on Day 3, nor in mice sacrificed on Day 5 without any behavioural manipulations, and significantly elevated in animals exposed to a context of testing on Day 5; group sizes as indicated above. As compared with intact mice (), in mice exposed to the modified swim test (), there was no change in GSK-3alpha mRNA levels nor (g) in the hippocampus, nor (h) in the prefrontal cortex. , ANOVA and Tukey’s multiple comparisons test; see the text; +10 min: mice sacrificed 10 min after swim session; +24 h: mice sacrificed 24 h after swim session; D3: mice exposed to the swim session on Day 3 instead of a swim on Day 5; Cont D5: mice exposed to a context of testing instead of a swim session on Day 5; no swim D5: mice were not exposed to a swim nor a context of swimming test prior a sacrifice. D1: Day 1; D2: Day 2; D5: Day 5. Data are mean ± SEM.