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Figure 3 | Journal of Neuroinflammation

Figure 3

From: CC chemokine ligand 2 upregulates the current density and expression of TRPV1 channels and Nav1.8 sodium channels in dorsal root ganglion neurons

Figure 3

CCL2 augments capsaicin-evoked inward currents and increases TRPV1 mRNA in neurons via activating phosphatidylinositol-3 kinase. (A) Following co-treating cultured dorsal root ganglion (DRG) neurons with chemokine CC chemokine ligand 2 (CCL2) (5 nM) and phosphatidylinositol-3 kinase (PI3K) inhibitor LY294002 (10 μM) for 24 to 36 hours, CCL2 failed to significantly enhance the amplitude of capsaicin (0.3 μM)-evoked inward current in a small-diameter DRG neuron. In the presence of ERK 1/2 inhibitor U0126 (20 μM), CCL2 still greatly augmented the magnitude of capsaicin currents in a small DRG sensory neuron. Holding potential (VH) = −60 mV. (B) Pretreating small-diameter DRG neurons with 5 nM CCL2 significantly increased the density of capsaicin-evoked inward currents. LY294002 (10 μM) almost completely blocked CCL2 enhancement of capsaicin currents, and U0126 (20 μM) failed to affect CCL2 potentiation of capsaicin currents. Each bar shows the mean ± standard error (SE) value of 10 to 13 neurons. (C) RT-PCR assays showed that CCL2 (5 nM) pretreatment significantly increased the transient receptor potential vanilloid receptor 1 (TRPV1) mRNA level of cultured DRG neurons. In the presence of 10 μM LY294002, CCL2 pretreatment of DRG sensory neurons for 24 to 36 hours failed to upregulate TRPV1 mRNA expression. Each bar represents the mean ± SE value of five experiments. *P <0.01 compared with control neurons.

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