FIGURE 3.

Transduction pathways involved in GAT-1 modulation by BDNF. A, effect of BDNF upon [³H]GABA uptake in the presence of inhibitors of the different signal-transducing pathways of TrkB receptor, namely U73122, LY294002, U0126, and GF109203x (for details, see “Results”), as indicated below the bars. B, Western blot analysis of PLC/pPLC, Akt/pAkt, and MAPK/pMAPK staining in total lysates of cells treated with BDNF, as indicated. In the upper panels are shown representative immunoblots, and the lower panels depict the quantitative densitometric analysis of the immunoreactivity of phosphorylated proteins; blots were probed with anti-PLC (1:750), pPLC (1:250), Akt (1:1500), pAkt (1:500), MAPK (1:6000), and pMAPK (1:500). In A, 100% on the ordinate corresponds to the amount of [³H]GABA taken up by astrocytes in the same experiments in the absence of any drug; in B, 100% on the ordinate corresponds to PLC/pPLC, Akt/pAkt, or MAPK/pMAPK staining in the absence of BDNF. The results are expressed as mean ± S.E. (error bars) from four (A) or three (B) independent experiments. *, p < 0.05 (one-way ANOVA followed by Bonferroni's post-test), as compared with no drug (first bar on the left) or, whenever indicated, with the closest bar on the left (absence of BDNF under same drug conditions).