Figure 5

Evaluation of spatial memory during the probe trial of 12-month-old APP/PS1 mice and wild type age-matched mice injected with saline or with D-Ala2 glucose-dependent insulinotropic polypeptide (GIP) for 27 days and reversal probe trial of 12-month-old mice injected for 31 days. Time spent in each quadrant of the water maze during the probe trial for wild type (WT) mice injected with (A) saline and with (B) D-Ala²GIP and APP/PS1 mice injected with (C) saline and with (D) D-Ala²GIP. Data represent mean ± standard error of the mean (SEM) of 11 WT mice injected with saline, 12 WT mice injected with D-Ala²GIP and 11 APP/PS1 per group. (E) Time spent in the target quadrant for all groups. (F) Time spent crossing the platform previously located during acquisition task. Data represent mean ± SEM of 11 WT mice injected with saline, 12 WT mice injected with D-Ala²GIP and 11 APP/PS1 per group (one-way analysis of variance, ANOVA). At 12 months, time spent in each quadrant of the water maze during the probe trial for WT injected with (G) saline and with (H) D-Ala²GIP and APP/PS1 mice injected with (I) saline and with (J) D-Ala²GIP. Data represent mean ± SEM of 11 WT mice injected with saline, 12 WT mice injected with D-Ala²GIP and 11 APP/PS1 per group (one-way ANOVA; post hoc test, *P < 0.05; **P < 0.01; ***P < 0.001). (K) Time spent in the target quadrant for all groups. (L) Time spent crossing the platform previously located during acquisition task (one-way ANOVA, * P < 0.05). (M) Evaluation of visual acuity of 12-month-old APP/PS1 mice and WT age-matched mice injected with saline or with D-Ala²GIP, during the visible platform task. Escape latency for the four trials was average for each mouse (one-way ANOVA).