Supplementary Figure 2: Modulation of the pharmacologically isolated I_NaP by local applications of substances that reduce [Ca²⁺]_e

(a) The inward current induced by voltage ramps from –80 to 0 mV (lower trace), after leak subtraction, under control conditions (black) is enhanced during local application of BAPTA (10 mM) (blue, n = 6 cells in 4 slices from 4 rats, control: 126.69 ± 40 pA vs BAPTA: 188 ± 54 pA, paired t-test; P = 0.021) and blocked by riluzole (20 µM) (grey, n = 4 cells in 4 slices from 3 rats). (b) The histograms illustrate the amplitude of the peak inward current during local application of BAPTA (n = 6 cells in 4 slices from 4 rats) and S100β (n = 7 cells in 5 slices from 5 rats) normalized to the control (n = 11 cells in 7 slices from 7 rats). (c) Pharmacologically-isolated trace of I_NaP obtained after subtracting the trace obtained with BAPTA and riluzole from the trace obtained with BAPTA alone (same cell as in (a)). (d) Voltage-dependency of I_NaP activation under control conditions (black) and during BAPTA (blue) and S100β (purple) application. I_NaP was normalized to the maximal value and fitted with a single Boltzmann function. Controls: V_1/2max = –53.8 ± 0.4 mV, slope factor of the fitted curve k = 7.4. BAPTA: V_1/2max = –60.2 ± 0.5 mV and k = 5.8. S100β: V_1/2max = –57.8 ± 0.7 mV and k = 6.1. Conductance was calculated with G = I/(V – E_rev). E_rev = –65 mV, based on the concentration of extracellular and intracellular pipette solutions.