Fig. 6

Differences between male and female rats in the BDNF/TrkB signaling pathway. Western blot analysis of BDNF (a) and phospho-TrkB (b) in male and female rats. a In control rats treated with vehicle (left panel), the basal level of BDNF expression was significantly higher in the NAc of female compared to male rats (p < 0.05). Repeated treatment with SKF 83959 (0.4 mg/kg s.c. × 5 days) significantly increased BDNF expression in the NAc of male rats (middle panel; p = 0.011), which was blocked by pre-treatment with TAT-D1 peptide (300 pmol i.c.v.; p < 0.05). Similar effects were observed in female rats (right panel; p = 0.0003). N = 6 rats/group. Data are means ± SEM. b A trend to higher phosphorylation level of TrkB (pTrkB) in the NAc of female rats compared to male rats was noted (left panel), but no statistical difference was observed (unpaired t test, p = 0.54). Treatments had a significant effect on pTrkB in the NAc (middle panel) of male rats (ANOVA; p = <0.0001), SKF 83959 treatment (0.4 mg/kg s.c. × 5 days) had no significant effect (t = 1.43), whereas TAT-D1 peptide pre-treatment (SKF59+TAT-D1) was significantly higher than both vehicle and SKF 83959 treatment. In female NAc (right panel), a clear effect of treatment was observed (ANOVA; p = 0.0003), with SKF 83959 increasing pTrkB in comparison to vehicle (p < 0.05), whereas pre-treatment with TAT-D1 blocked the effect of SKF 83959 (p < 0.05). N = 6 rats/group. Data are means ± SEM