Fig. 6.

Independence of the ATP effect on K⁺ and Na⁺. a The effect of ATP is independent of K⁺ ions. The dashed vertical line indicates that an OHC was alternatively perfused with NES and 20 mM Cs⁺ extracellular solution (130 NaCl, 20 CsCl, 2 CaCl₂, 1.47 MgCl₂, and 10 HEPES in mM) to replace extracellular K⁺. The patch pipette was also filled with 140 mM Cs⁺ to replace K⁺ (Cs pipette: 140 CsCl, 10 EGTA, 2 MgCl₂, and 10 HEPES in mM). b and c The effect of ATP on OHC electromotility-associated NLC is independent of extracellular Na⁺. The patch pipette was filled with a BAPTA-buffered intracellular solution. The OHC was perfused with a Cs-based extracellular solution (Cs-ES), which Na⁺ and K⁺ were replaced with 140 mM Cs⁺ (140 CsCl, 2 CaCl₂, 1.47 MgCl₂, and 10 HEPES in mM)