FIGURE 7.

Ciliary TRPV4 activity. (A) In a single cilium, the ciliary current-voltage relation was measured in the absence of the TRPV4 agonist GSK1016790A (black), in its presence (50 nM, red), and again in its absence (orange). (B) Single-channel current fluctuations observed in the presence of 50 nM GSK1016790A at the membrane potentials shown. (C) Single-channel current-voltage relation from −140 to +80 mV (open circles). The internal solution contained 50 nM GSK1016790A. At each voltage, single-channel current was measured in from 3 to 11 cilia. The blue lines show the best linear fits and have slopes (single-channel conductances) of 39 pS (−140 to −60 mV) and 90 pS (+20 to +80 mV). The relation shown in gray is the average of the macroscopic currents activated by 50 nM GSK1016790A in each of 8 cilia. Leak currents measured in the absence of GSK1016790A were subtracted. The current scales of the single-channel and macroscopic currents are different and are both shown on the y-axis. The scales were chosen to facilitate comparison of the single-channel and macroscopic current-voltage relations. In all parts of this figure, Ca²⁺ was buffered with 0.25 mM BAPTA.