At low doses, trazodone's 5-HT2A receptor antagonism removes tonic inhibition on BDNF release, allowing sustained TrkB receptor activation in cortical and hippocampal neurons. This elevates CREB phosphorylation, drives synaptic protein synthesis (PSD-95, Synapsin-1), and preserves dendritic spine density against A-beta oligomer-induced spine loss. However, the claim that ~40-60% 5-HT2A occupancy is the effective threshold is not grounded in human PET data, and BDNF/TrkB signaling can lead to both neuroprotective and pro-apoptotic outcomes via p75NTR depending on neuronal context.
Curated pathway from expert analysis
flowchart TD
A["HTR2A (5-HT2A)<br/>Serotonin Receptor"]
B["BDNF<br/>Brain-Derived Neurotrophic Factor"]
C["NTRK2 (TrkB)<br/>Neurotrophin Receptor"]
D["CREB<br/>Transcription Factor"]
E["Synaptic<br/>Plasticity"]
F["Sustained<br/>Neuroprotection"]
G["Cognitive<br/>Enhancement"]
A --> B
B --> C
C --> D
D --> E
E --> F
F --> G
style A fill:#1a237e,stroke:#4fc3f7,color:#4fc3f7
style B fill:#1b5e20,stroke:#a5d6a7,color:#a5d6a7
style G fill:#1b5e20,stroke:#a5d6a7,color:#a5d6a7No linked papers recorded for this hypothesis yet.
No curated PDB or AlphaFold mapping for 5-HT2A yet. Search RCSB →
Median TPM across 13 brain regions for 5-HT2A receptor (HTR2A), BDNF, TrkB (NTRK2), CREB from GTEx v10.
No clinical trials data linked to this hypothesis yet.
No curated ClinVar variants loaded for this hypothesis.
Run scripts/backfill_clinvar_variants.py to fetch P/LP/VUS variants.
No DepMap CRISPR Chronos data found for 5-HT2A receptor (HTR2A), BDNF, TrkB (NTRK2), CREB.
Run python3 scripts/backfill_hypothesis_depmap.py to populate.
No resource usage or linked notebooks recorded for this hypothesis yet.
| Prediction | Predicted | Observed | Status | Conf |
|---|---|---|---|---|
| IF C57BL/6J mice receive trazodone (30 mg/kg, i.p.) for 14 consecutive days, THEN cortical BDNF protein concentration will increase by ≥30% and TrkB phosphorylation (p-TrkB Y516) will rise by ≥1.5-fol | BDNF protein levels in prefrontal cortex will reach ≥300 pg/mg tissue (vs. ~230 pg/mg baseline); p-TrkB/total-TrkB ratio will exceed 0.45 (vs. ~0.30 vehicle) | — no observation — | pending | 0.65 |
| IF primary mouse cortical neurons are pre-treated with 5-HT2A antagonist (trazodone 100 nM, 24h) before A-beta1-42 oligomer exposure (500 nM, 24h), THEN mushroom spine density will remain ≥75% of base | Spine density ≥0.45 mushroom spines/μm (baseline ~0.60); PSD-95/GAPDH ratio ≥0.65 (baseline ~0.90); p75NTR co-activation reduces these metrics by ≥40% | — no observation — | pending | 0.58 |