Figure 3.

Inhibition of kinase activity induces a shift in the V_1/2 of TRPM8 toward negative membrane potentials and an increase in the g_max. A, Representative recordings of whole-cell currents measured at 100 and −60 mV in a stable mTRPM8-myc expressing HEK293 cell line in control condition (open circles) or preincubated for 10-15 min with 200 nm staurosporine (Sta.) (red circles). B, Scatter plots with mean and SD of maximal current density at 100 and −60 mV. Statistical significance was assessed with a two-tailed unpaired Student's t test with Welch's correction (Cold_100mV: t₍₂₃₎ = 7.11, p < 0.0001; Menthol_100mV: t₍₂₆₎ = 6.08, p < 0.0001; Cold+menthol_100mV: t₍₂₃₎ = 3.57, p = 0.0016; Cold_-60mV: t₍₂₄₎ = 3.18, p = 0.0041; Menthol_-60mV: t₍₁₉₎ = 0.72, p = 0.4819; Cold+menthol_-60mV: t₍₂₄₎ = 4.93, p < 0.0001). C, I–V relationships in Control (Ctrl.), Cold (C), Menthol (M), and Cold+menthol (C + M) of cells in A. Superimposed green line on each trace indicates the fit of the current to Equation 1 (see Materials and Methods). D, Scatter plots with mean and SD of the V_1/2 values in the presence of the different agonists. E, Scatter plots represent mean and SD g_max values estimated in the Cold+menthol condition. Statistical significance was assessed with a two-tailed unpaired Student's t test with Welch's correction: V_1/2 Cold: t₍₂₆₎ = 5.63, p < 0.0001; V_1/2 Menthol: t₍₂₄₎ = 4.45, p = 0.0002; V_1/2 Cold+menthol: t₍₃₁₎ = 2.88, p = 0.0071; g_max: t₍₂₄₎ = 2.80, p = 0.0099. **p < 0.01. ***p < 0.001. n > 15 cells for each condition.