Postsynaptic Density (PSD-95) & Kinase Cascade
Activity: Enhanced
GluA1 AMPAR
NMDAR
BRAF Kinase
p-ERK1/2
Inhibitor (Dabrafenib)
PSD-95 Matrix
Patch Clamp Oscilloscope (Lamina I/II Neurons)
Peak EPSC: 428.5 pA
Decay Tau (τ): 8.4 ms
Windup Gain: 2.8x
Withdrawal Thr: 1.2 g (Allodynia)
1. Peripheral Injury Model
Afferent State
Spared Nerve Injury induces persistent retrograde signaling, driving cytosolic BRAF translocation directly into dorsal horn dendritic spines.
2. Synaptic Kinase Cascade
Biochemical Gain
3. Stimulation Protocol
Dorsal Root Input
4. Targeted Kinase Pharmacology
Therapeutic Rescue
Pharmacological Dose-Response (Hill Equation)
EPSC Inhibition: 74.2%
Log[Concentration] (nM) vs. Synaptic Current (% Max)
Apparent IC50: ~5.2 nM (Dabrafenib)
Molecular Sensitization Sequence
1. Peripheral Nerve Axotomy / Injury 0 ms
Damaged primary afferents fire ectopic bursts and release trophic factors, initiating retrograde injury cascade to the spinal cord.
2. BRAF Dendritic Spine Recruitment + Minutes to Hours
Cytosolic BRAF translocates directly to the postsynaptic density (PSD-95), anchoring near glutamate receptor complexes.
3. MEK1/2 → ERK1/2 Kinase Cascade Amplification Stage
Synaptic BRAF hyper-phosphorylates MEK and downstream ERK1/2, creating an active nanodomain kinase cluster.
4. GluA1-S845 Phosphorylation & Insertion Receptor Gating
AMPA receptor open probability increases; reserve pools rapidly traffic to synaptic surface, amplifying single-quantum EPSCs.
5. Central Sensitization & Allodynia Hyperexcitability
Low-threshold touch afferents now drive high-frequency spinal dorsal horn firing, translating innocent touch into intense pain.