Figure 4.

Effects of hBDNF^Val66Met genotype and prior CORT exposure on TrkB isoforms. (a) hBDNF^Met/Met mice have (subtly) higher fl.TrkB expression relative to hBDNF^Val/Val mice in the DHP, while chronic CORT tends to (b) decrease tr.TrkB expression while (c) increasing TrkB^Y515 phosphorylation in this brain region. In the VHP, (d) fl.TrkB was unchanged however (e) hBDNF^Met/Met mice tended to have lower tr.TrkB expression than hBDNF^Val/Val mice. (f) CORT treatment increased pTrkB^Y515 phosphorylation in the VHP. In the mPFC, (g) fl.TrkB was once more unchanged. (h) However, a significant genotype × treatment interaction emerged for tr.TrkB expression whereby hBDNF^Val/Val mice selectively responded to chronic CORT. Following CORT, expression levels of tr.TrkB in the mPFC of hBDNF^Val/Val mice were reminiscent of those observed in the mPFC of hBDNF^Met/Met mice. (i) Lastly, as in the DHP and VHP, a history of CORT also increased pTrkB^Y515 phosphorylation in the mPFC. All data presented as mean±SEM; *P<0.05, **P<0.01, and ***P<0.001. Per group, n=9–14.