Fig. 4. Effect of ATP on spatially resolved single-channel recordings in primary cilia. (A) Normalised mean open probability PO of channels in control (black symbols) and presence of 10ÁM ATP in the pipette solution (red symbols) at the base of cilia, the tip of cilia, and at randomly selected areas of the extra-ciliary membrane (ExC). (B) Representative excerpts of single-channel activity at pipette potentials of 100mV and -100mV recorded at the base of a cilium in control conditions (black) and in presence of ATP (orange). * p<0.05. Voltages shown are nanopipette potentials against the ground electrode. All recordings are in the cell-attached configuration.