Fig. 4.

Activation of TrkB receptors in CA3 stratum lucidum following stimulation of MF is impaired in symptomatic male Mecp2 mutant mice. (Left) Representative examples of immunohistochemical labeling with antibodies against phospho-TrkB receptors in acute slices before (control) and after three sets of TBS to the MF tract in CA3 stratum lucidum in wild-type (Upper) and Mecp2 mutant mice (Lower). (Right) Semiquantitative analysis of phospho-TrkB immunoreactivity. The intensity of phospho-TrkB IHC staining after stimulation was significantly lower in Mecp2 mutant slices than in wild-type slices, although both were increased compared with the naïve controls of the corresponding genotype. Preincubation with the BDNF scavenger TrkB-IgG (1 μg/mL) completely abolished the increase in phospho-TrkB immunoreactivity after TBS in Mecp2^−/y slices (Lower Right). Inset shows higher magnification images from the corresponding sections. SP, stratum pyramidale; SL, stratum lucidum; SO, stratum oriens. (Scale bar: 10μm). *P < 0.05.