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Figure 6 | Molecular Pain

Figure 6

From: Tumor necrosis factor-alpha (TNF-α) enhances functional thermal and chemical responses of TRP cation channels in human synoviocytes

Figure 6

Delayed response of SW982 synoviocytes to hypotonic challenge 12–16 hr after TNF-α pretreatment. (A) Representative calcium activity traces show that after prolonged TNF-α pre-treatment (1 ng/ml, 12 hrs), SW982 synoviocytes actively responded to 50% hypotonic saline stimulation (150 mOsm/l). (B) A decrease in osmolarity (50%, 10 min) promotes a ruthenium red-sensitive (RR 3 μM, 10 min) intracellular calcium elevation in about 11% of the SW982 synoviocytes. TNF-α (1 ng/ml) pre-treatment for 12 or 16 hr triggers increased intracellular activity in a greater percentage of cells following hypotonic bath application (and see Additional file 2). The increased number of activated cells in hypotonic conditions is effectively blocked by bath application of ruthenium red (3 μM, 10 min). (C) The bar graphs show average responses (nM) of SW982 synoviocytes after different pretreatments. Hypotonic stimulation alone (50%, 10 min) does not significantly affect the average response of SW982 cells. The same hypotonic challenge in cells pre-treated with TNF-α (1 ng/ml) for 12 hr or 16 hr triggers a ruthenium red (RR)-sensitive intracellular calcium elevation. TNF-α pretreatment + hypotonic saline vs. non-treatment control + Hypotonic saline, p < 0.001 ##; TNF-α pretreatment + Hypotonic saline vs. TNF-α + RR + Hypotonic saline, p < 0.001 ###. (D) Pre-treatment with TNF-α significantly increased the percentage of cells responding to the 50% hypotonic challenge. The increase in responsive cells was significantly blocked by ruthenium red. TNF-α pretreatment + Hypotonic saline vs. non-treatment control + Hypotonic saline, 12 h p < 0.05 *; 16 h p < 0.005 **; TNF-α pretreatment + Hypotonic saline vs. TNF-α + RR + Hypotonic saline, 12 h and 16 h p < 0.05 ***. The X-axis marker in (C) and the N numbers of cells shown in (D) apply to both panels (C) and (D).

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