Activation of ICl,swell in CFPAC cells requires TMEM16A channels. A, RT-PCR analysis indicates expression of TMEM16A, TMEM16F, and TMEM16H in CFPAC cells. M, marker; A–K, TMEM16A–K. Gs, Gl, short and long splice variants. B, original recordings of whole cell currents in CFPAC cells activated by hypotonic bath solution (33%). Cells were voltage clamped in intervals from −50 to +50 mV. Treatment with siRNA for TMEM16A (si16A) reduced the swelling-activated whole cell current, when compared with cells treated with scrambled (scrbld) RNA. C, summary of swelling-activated whole cell conductance (GHypo) measured in CFPAC cells treated with scrambled RNA or after RNA interference knockdown of TMEM16A, CLC-3, and CLCA proteins. Mean ± S.E., (n) = number of cells measured. #, significant inhibition of ICl,swell by RNA interference knockdown of TMEM16A when compared with treatment with scrambled RNA (unpaired t test).