Figure 5.

Characterization of TRPM8 variant function in lung epithelial cells. (A) Concentration-dependent increases in [Ca²⁺]i by menthol in NHBE (squares), BEAS-2B (triangles), and DU-145 cells (diamonds). No Ca²⁺ flux was observed in CHO cells (circles). (B) Increased [Ca²⁺]i in NHBE (squares), BEAS-2B (triangles), and DU-145 cells (diamonds) exposed to cold (18°C) for various time points. No Ca²⁺ flux was observed in CHO cells (circles). Data represent mean fluorescence values normalized to untreated controls and standard deviation (n = 3). An asterisk represents concentrations at which statistically significant (ANOVA, P ≤ 0.05) increases in [Ca²⁺]i were observed. (C) TRPM8 variant-mediated Ca²⁺ flux induced by 3 mM menthol in the presence of EGTA (100 μM) or after depletion of ER Ca²⁺ with thapsigargin (1.5 μM) in NHBE and BEAS-2B cells. Data represent mean fluorescence values normalized to the untreated controls, and standard deviation (n = 3). Values significantly (paired t test, P ≤ 0.05) different from untreated and menthol-treated cells are represented by * and #, respectively.