Fig. 8.

Lack of channel block by amiloride and by antagonists of Ca²⁺-activated K⁺ channels. Left: in 7 cilia with the large-conductance channel, mean channel current was measured in the absence (control) and presence of 1 mM cytoplasmic amiloride. Right: in 8 cilia with the large-conductance channel, the effect of a mixture of blockers of Ca²⁺-activated K⁺ channels was determined. For both parts of this figure, mean channel current was measured as the mean current minus the current attributed to leak channels. The latter was determined from an amplitude histogram. The control current was arbitrarily assigned a value of 100. The standard external solution was used to bathe the cell and to fill the pipette; the cytoplasmic solution contained 0.1 µM or 3 µM free Ca²⁺. For both antagonists, holding potentials ranging from −20 to +70 mV were tested.