Table 1.

Summary of properties of ClC channels/antiporters

Cl− Channel Type	Sensitivity to DIDS	Sensitivity to Niflumic Acid	Permeability Sequence	Sensitivity to Extracellular pH
ClC-3	Yes (1, 7, 8, 36) No (20)	Yes (1, 5, 12) No (low concentrations) (7)	I− > Br− > Cl− > gluconate (35) I− > Cl− (8) Cl− > I− (20) SCN− > I− > Br− > Cl− >> aspartate (36)	pH↓ to 6.35 → $I_{{\text{Cl}}^{-}}$↓ pH↓ to 5.5 → $I_{{\text{Cl}}^{-}}$↑ (21, 22) pH↓ to 6.6 → $I_{{\text{Cl}}^{-}}$↑ pH↓ to 5.8 → no change in $I_{{\text{Cl}}^{-}}$ (35)
ClC-4	Yes (17)	Yes (15)	I− > Cl− > F− (17) I− = $\text{N}{\text{O}}_3^{-}$ > Br− > Cl− (15) I− >> Br− = Cl− > $\text{N}{\text{O}}_3^{-}$ (15) $\text{N}{\text{O}}_3^{-}$ > Cl− > Br− > I− (10, 15) SCN− >> $\text{N}{\text{O}}_3^{-}$ >> Cl− > Br− ≈ ≈ I− >> aspartate (34)	pH↓ → $I_{{\text{Cl}}^{-}}$↓ (10, 15, 25, 34) pH↓ → $I_{{\text{Cl}}^{-}}$↑ (15, 17)
ClC-5	No (31)	No (31)	$\text{N}{\text{O}}_3^{-}$ > Cl− > Br− > I− >> glutamate (31) $\text{N}{\text{O}}_3^{-}$ > Cl− > Br− > I− (10)	pH↓ → $I_{{\text{Cl}}^{-}}$↓ (6, 10, 28)
ClC-6	Yes (24)	N/A	$\text{N}{\text{O}}_3^{-}$ > I− > Br− > Cl− > gluconate (4) Cl−>I− (24)	N/A
ClC-7	Yes (18)	Yes (18)	Cl− > Br− > $\text{N}{\text{O}}_3^{-}$ > I− > gluconate (19) $\text{N}{\text{O}}_3^{-}$ > Cl− > Br− > I− > MsO− (13)*	pH↓ → $I_{{\text{Cl}}^{-}}$↑ (18) pH↓ → $I_{{\text{Cl}}^{-}}$↓ (19)
DSM Cl− channel	Yes (37)	Yes (37)	Cl− > Br− > I− > MsO− (37)	pH↓ → $I_{{\text{Cl}}^{-}}$↑ (present paper)

In the pH sensitivity column, vertical arrows indicate the direction of pH or Cl⁻ current ($I_{{\text{Cl}}^{-}}$) change, and horizontal arrows link pH change to the current alteration. ClC, voltage-dependent Cl⁻ channel/antiporter; DIDS, 4,4′-diisothiocyano-2,2′-stilbenedisulfonic acid; DSM, detrusor smooth muscle; MsO⁻, methanesulfonate; N/A, not available; SCN⁻, thiocyanate.

^*Data obtained from Cl⁻ flux assay (13).