Slack and Slick channel currents are insensitive to extracellular Cl−. A: a, control current of Slack-transfected cell; b, 5 mM Cl−; c, current-voltage relationship of Slack for control (■) and 5 mM Cl− (○). B: a, control current of Slick-transfected cell; b, 5 mM Cl−; c, current-voltage relationship of Slick for control (■) and 5 mM Cl− (○).