Figure 2. TFL₄₅₇ interferes TrkB‐FL downregulation and prevents acute and chronic excitotoxicity.

• A
  Effect of TFL₄₅₇, TFL₄₈₂, and TFL₅₄₁ on TrkB‐FL levels. Cultures preincubated with TrkB‐FL peptides or TMyc (25 μM, 30 min), followed by chronic NMDA treatment (2 h), were compared to cells without peptide. Levels of full‐length (FL) TrkB were established with panTrkB, an antibody for the extracellular domain that also detects the truncated forms (tTrkB).
• B
  Quantitation of peptide interference of TrkB‐FL downregulation. Receptor levels were normalized to NSE and expressed relative to values obtained in cultures without peptide or NMDA. Means ± SEM are represented, and analysis was performed by ANOVA test followed by post hoc Tukey's HSD test (*P = 0.02; n = 4).
• C
  Effect of TFL₄₅₇, TFL₄₈₂, and TFL₅₄₁ on neuronal viability after chronic excitotoxicity. Cultures were preincubated with peptides and treated with NMDA for 0–6 h as before. Values for each time point were represented relative to those of neurons incubated with the same peptide but no NMDA. Mean ± SEM of eleven (TFL₄₅₇), three (TFL₄₈₂), and seven (TFL₅₄₁) independent experiments is given. Data were analyzed by a two‐way ANOVA test followed by post hoc Bonferroni test comparing values for each time point (***P = 0.0002, ***P = 0.00009, and *P = 0.0357, respectively for 2, 4, or 6 h).
• D
  Effect of TFL₅₁₈ on TrkB‐FL levels. Cultures incubated with TFL₅₁₈ as before were compared to those treated with TMyc or TFL₄₅₇.
• E
  TFL₅₁₈ effect on neuronal viability. Cultures were treated and data analyzed as indicated in (C). No significant differences were found for TFL₅₁₈ while neuroprotection by TFL₄₅₇ was confirmed (***P = 0.0002 and **P = 0.002, respectively, for 2 or 4 h compared to TMyc; n = 3).
• F
  Effect of TFL₄₅₇ on neuronal viability after acute excitotoxicity. Cells were induced with NMDA (50 μM) and glycine (10 μM) for 1 h and, after agonists removal, culture proceeded for 20 h with DL‐AP5 (200 μM) and TMyc or TFL₄₅₇ (15 μM). Mean ± SEM relative to cultures incubated with TMyc but no NMDA is represented. Analysis was performed by unpaired Student's t‐test (*P = 0.04; n = 5).

Source data are available online for this figure.