Fig. 2.
M4P blocks TRPM4 channel currents. a Time course of normalised currents by membrane capacitance at + 100 mV and − 100 mV from ramp protocols applied from − 100 to + 100 mV. The pipette solution contained a calculated 7.4 μM free Ca2+. The current-voltage relationships before desensitisation were presented as means ± s.e.m. in the middle panel. Summary of current densities at − 100 mV and 100 mV before desensitisation is shown on the right. Data were obtained from 19 cells for IgG and 15 cells for M4P. b Current-voltage relationship for M4P (n = 10) and rabbit IgG (n = 12) treatments from 250-ms voltage ramps after 1 min (left panel) and 7 min (middle panel) hypoxia treatment. Summary of current at − 100 mV and 100 mV under the same conditions is shown on the right. c Normalised current by membrane capacitance (Cm) of M4P or rabbit IgG-treated cells after 1 min and 7 min hypoxia treatment. d Time course of membrane capacitance (Cm) changes with IgG (n = 12) or M4P (n = 10) treatment under hypoxic conditions. HEK 293 cells (n = 13) under normoxic conditions were recorded as control. No difference was observed between M4P and control groups. e Summary of cell death after 24 h OGD with the treatment of M4P or IgG. n = 4 experiments. For a–d, TRPM4-transfected HEK 293 cells were incubated with 20.8 μg/ml IgG or M4P for 30 min before patch-clamping. In a, b, c, and e, statistical analysis was performed by two-tailed unpaired Student’s t test; in d by two-way ANOVA with Bonferroni’s post hoc analysis. *p < 0.05, **p < 0.01, ***p < 0.001, and #p < 0.0001. ns non-significant