Fig. 6.

Crofelemer inhibition of calcium-activated Cl⁻ channels. A, apical membrane current in TMEM16A-expressing FRT cells in the presence of a transepithelial Cl⁻ gradient (apical [Cl⁻], 70 mM; basolateral [Cl⁻], 140 mM). B, crofelemer concentration-dependence of TMEM16A Cl⁻ current inhibition. C, whole-cell TMEM16A current recorded at a holding potential of 0 mV and pulsing to voltages between ± 100 mV in steps of 20 mV in the absence and presence of 10 μM crofelemer. TMEM16A was stimulated by 100 μM ATP. D, I-V plot of mean currents (at the middle of each voltage pulse). Mean currents were normalized as current densities (measured in picoamperes per picofarads).