Fig. 8. TrkB.T1 is endogenously expressed in hippocampal neurons and glia. (A) untransfected rat hippocampal microcultures were stained at 10 DIV with an antibody that selectively reacts with truncated TrkB receptors (TrkB[TK–]). (B) As a positive control, rat hippocampal neurons were transfected at 9 DIV with wt TrkB.T1 receptor and also processed for TrkB [TK–] immunocytochemistry. Neurons were identified by co-staining with a MAP2 antibody. Truncated TrkB receptors can be immunostained in untransfected neurons (arrows) and glia (asterisk). Specificity of the TrkB[TK–] antibody was evident from the intense signal in TrkB.T1-overexpressing neurons in B. Owing to the tenfold shorter exposure time for the overexpressed truncated receptor staining in the glia is not visible in B (lower panel). Scale bar: 10 µm.