Cl⁻ reduces the number of channels detected by noise analysis. (A) Representative whole cell currents and current variances obtained in a cell stably expressing ClC-4 sequentially perfused with extracellular solution containing 100% SCN⁻, 50% SCN⁻ plus 50% gluconate, and 50% SCN⁻ plus 50% Cl⁻. An intracellular I⁻-based solution was used. (B) Current–variance plots of the data in A. Lines represent fits with standard parabolic function. (C) Linear transformation of the data in B. Note the different slope resulting when 50% of SCN⁻ anions were substituted with 50% Cl⁻ or gluconate. Lines represent linear fits to the data.