FIGURE 6.

TRPM4 current is insensitive to Ca²⁺ buffering. (A) Steady-state activity was measured at +60 mV in each of two internal solutions. The first of these (top and bottom recordings) had 10 µM free Ca²⁺ buffered with 2 mM dibromoBAPTA. The other solution had 15 nM free Ca²⁺ buffered with 0.1 mM BAPTA. (B) Paired mean steady-state currents at +60 mV for 18 cilia, each tested in each of the two internal solutions. *p < 0.001. (C) Mean steady-state currents at +60 mV in 10 µM free Ca²⁺ buffered with 2 mM dibromoBAPTA in cilia from wild-type cells (WT, n = 18 cilia) or cells in which TRPM4 was knocked down with shRNA (KD, n = 8 cilia). The values for wild-type cells are taken from Figure 6B. *p < 0.001. (D) Absence of transient activation of TRPM4 in the internal solution containing 15 nM free Ca²⁺ buffered with 0.1 mM BAPTA. The current shown was measured at +60 mV immediately following a prepulse of 10 s to −140 mV. Recordings in parts A and D are from the same cilium.